From galactorrhea to osteopenia: rethinking serotonin-prolactin interactions

Sertraline-Induced Galactorrhoea: A Case Report

Patients taking various treatments frequently report galactorrhoea as a side effect. Psychotropic drugs, especially neuroleptics, are among the treatments most likely to cause this effect. Conventional tricyclic antidepressants rarely cause galactorrhea. The advent of new selective serotonin reuptake inhibitor (SSRI) antidepressants purported to reduce such side effects. We report the clinical case of a patient with galactorrhoea on Sertraline as well as our therapeutic approach in light of data from recent scientific literature.

Exposure to psychotropic drugs and breast cancer risk in patients with bipolar disorder and major depressive disorder: a nested case-control study

Breast cancer is one of the most prevalent and serious types of cancer globally. Previous literature has shown that women with mental illness may have an increased risk of breast cancer, however whether this risk is associated with the use of psychotropic drugs has yet to be elucidated. This study aimed to assess such risk among women with major depressive disorder (MDD) and bipolar disorder (BD). A nested case-control study design was used with data obtained from the Taiwan National Health Insurance Research Database. Logistic regression analysis with adjustments for demographic characteristics, medical and mental comorbidities, and all-cause clinical visits was performed to estimate the risk of breast cancer according to the cumulative defined daily dose (cDDD) of psychotropic drugs. The study included 1564 women with MDD or BD who had breast cancer, and 15,540 women with MDD or BD who did not have breast cancer. After adjusting for important confounders, the long-term use of valproic acid (odds ratio, 95% confidence interval: 0.58, 0.39-0.56, cDDD ≥ 365), citalopram (0.58, 0.37-0.91, cDDD 180-365), and sertraline (0.77, 0.61-0.91, cDDD ≥ 365) was associated with a lower risk of breast cancer compared to a cDDD < 30. The short-term use of fluvoxamine (0.82, 0.69-0.96, cDDD 30-180), olanzapine (0.54, 0.33-0.89, cDDD 30-179), risperidone (0.7, 0.51-0.98, cDDD 30-179), and chlorpromazine (0.48, 0.25-0.90, cDDD 30-179) was associated with a lower risk of breast cancer. We found no evidence of an increased risk of breast cancer in patients with MDD or BD receiving psychotropic drugs.

A Meta-Analysis of Antipsychotic-Induced Hypo- and Hyperprolactinemia in Children and Adolescents

Objective: Antipsychotic-related prolactin changes may expose children and adolescents to severe adverse reactions (ARs) related to pubertal development and growth. We therefore aimed to assess the effects of antipsychotics on prolactin levels and associated somatic ARs in children and adolescents. Methods: We systematically searched PubMed and CENTRAL for placebo-controlled randomized trials of antipsychotics in children and adolescents aged ≤18 years, reporting prolactin levels and related ARs. We conducted a random-effect meta-analysis and assessed risk of bias version 2 (ROB2). Results: Thirty-two randomized controlled trials with an average trial duration of 6 weeks, covering 4643 participants with an average age of 13 years and a male majority of 65.3%. Risk of bias across domains was low or unclear. The following antipsychotic compounds: aripiprazole (n = 810), asenapine (n = 506), lurasidone (n = 314), olanzapine (n = 179), paliperidone (n = 149), quetiapine (n = 381), risperidone (n = 609), and ziprasidone (n = 16) were compared with placebo (n = 1658). Compared with placebo, statistically significant higher prolactin increase occurred with risperidone (mean difference [MD] = 28.24 ng/mL), paliperidone (20.98 ng/mL), and olanzapine (11.34 ng/mL). Aripiprazole significantly decreased prolactin (MD = -4.91 ng/mL), whereas quetiapine, lurasidone, and asenapine were not associated with significantly different prolactin levels than placebo. Our results on ziprasidone are based on a single study, making it insufficient to draw strong conclusions. On average, 20.8% of patients treated with antipsychotic developed levels of prolactin that were too high (hyperprolactinemia), whereas only 1.03% of patients reported prolactin-related ARs. Data were highly limited for long-term effects. Conclusions: In children and adolescents, risperidone, paliperidone, and olanzapine are associated with significant prolactin increase, whereas aripiprazole is associated with significant decrease. Despite the significant changes in prolactin level, few ARs were reported. Study protocol on PROSPERO: CRD42018116451.

Omeprazole-induced galactorrhea in kidney transplant patients-a case report

BACKGROUND

Omeprazole belongs to the pharmacological classifications of proton pump inhibitors and is a widely used medicine. All proton pump inhibitors have a common mechanism of action and are prodrugs that require activation in an acidic environment. Omeprazole is extensively metabolized in the liver by cytochrome 2C19 and cytochrome 3A4, which are responsible for drug interactions. Omeprazole-induced galactorrhea is a rare adverse event of drug metabolism and is often underreported.

CASE PRESENTATION

This is a case of a 26-year-old unmarried Asian (Bhutanese) female who underwent kidney transplant and was administered standard antirejection medication (tacrolimus, prednisolone, and leflunomide) along with an antihypertensive agent. She came to the emergency department with complaints of nausea, vomiting, abdominal pain, chronic gastritis, anemia, hypertension, and loss of appetite. The tacrolimus trough level was in the subtherapeutic range at admission. The tacrolimus dose was adjusted, and oral omeprazole was administered. After 3 days, she experienced milk production from her left breast, which according to the patient was her second incidence after omeprazole ingestion.

CONCLUSION

Causality assessment using Naranjo's algorithm and recovering from galactorrhea after stopping omeprazole and omeprazole rechallenge with the reappearance of galactorrhea confirmed omeprazole as the causative agent. Tacrolimus interferes with omeprazole metabolism and increases tacrolimus levels in the blood. Caution needs to be taken when omeprazole is administered with other drugs that interfere with metabolizing enzymes.

A prolactin-dependent sexually dimorphic mechanism of migraine chronification

OBJECTIVE

Determination of possible sex differences in mechanisms promoting migraine progression and the contribution of prolactin and the prolactin long (PRLR-L) and short (PRLR-S) receptor isoforms.

BACKGROUND

The majority of patients with chronic migraine and medication overuse headache are female. Prolactin is present at higher levels in women and increases migraine. Prolactin signaling at the PRLR-S selectively sensitizes nociceptors in female rodents, while expression of the PRLR-L is protective.

METHODS

Medication overuse headache was modeled by repeated sumatriptan administration in male and female mice. Periorbital and hindpaw cutaneous allodynia served as a surrogate of migraine-like pain. PRLR-L and PRLR-S isoforms were measured in the trigeminal ganglion with western blotting. Possible co-localization of PRLR with serotonin 5HT1B and 5HT1D receptors was determined with RNAscope. Cabergoline, a dopamine receptor agonist that inhibits circulating prolactin, was co-administered with sumatriptan. Nasal administration of CRISPR/Cas9 plasmid was used to edit expression of both PRLR isoforms.

RESULTS

PRLR was co-localized with 5HT1B or 5HT1D receptors in the ophthalmic region of female trigeminal ganglion. A single injection of sumatriptan increased serum PRL levels in female mice. Repeated sumatriptan promoted cutaneous allodynia in both sexes but down-regulated trigeminal ganglion PRLR-L, without altering PRLR-S, only in females. Co-administration of sumatriptan with cabergoline prevented allodynia and down-regulation of PRLR-L only in females. CRISPR/Cas9 editing of both PRLR isoforms in the trigeminal ganglion prevented sumatriptan-induced periorbital allodynia in females.

INTERPRETATION

We identified a sexually dimorphic mechanism of migraine chronification that involves down-regulation of PRLR-L and increased signaling of circulating prolactin at PRLR-S. These studies reveal a previously unrecognized neuroendocrine mechanism linking the hypothalamus to nociceptor sensitization that increases the risk of migraine pain in females and suggest opportunities for novel sex-specific therapies including gene editing through nasal delivery of CRISPR/Cas9 constructs.

Effect of sertraline on depression severity and prolactin levels in women with polycystic ovary syndrome: a placebo-controlled randomized trial

There is a paucity of data regarding the safety and efficacy of antidepressant therapy in women with polycystic ovary syndrome and depression. The effect of antidepressant medications on circulating prolactin levels is of concern in this patient population. We aimed to evaluate the effect of sertraline on depression severity and serum prolactin levels in women with polycystic ovary syndrome and mild-to-moderate depression. In a parallel-design, two-center, randomized controlled trial, we stratified participants according to their baseline prolactin level into normal (<25 ng/mL) and high (≥25 ng/mL) prolactin groups. Each group was randomized to receive 50 mg daily sertraline (up-titrated after 25 mg daily for 1 week) or placebo. The enrolling physicians, outcome assessors, and study subjects were all blind to the treatment. Depression severity was assessed by the Hamilton depression rating scale at baseline, the third, and the sixth weeks. The primary efficacy outcome was a change in depression severity. Prolactin levels were checked at baseline and after 6 weeks, and the safety outcome was the alteration in prolactin levels. Overall, 513 women were screened for eligibility in two outpatient clinics. Ultimately, 74 (38 normal prolactin and 36 high prolactin level) individuals were randomized. After 6 weeks of follow-up, depression severity was significantly reduced among patients who received sertraline regardless of the baseline prolactin levels (all between subjects P < 0.001). Furthermore, there was no difference in prolactin levels between the sertraline and placebo arms in normal (P = 0.80) or high prolactin (P = 0.21) groups. Sertraline is a well-tolerated and effective choice for treating depression in women with polycystic ovary syndrome. Future studies with longer follow-up periods are required to draw more robust conclusions.

Hyperprolactinemic African elephant (Loxodonta africana) females exhibit elevated dopamine, oxytocin and serotonin concentrations compared to normal cycling and noncycling, low prolactin elephants†

Many zoo elephants do not cycle normally, and for African elephants, it is often associated with hyperprolactinemia. Dopamine agonists successfully treat hyperprolactinemia-induced ovarian dysfunction in women, but not elephants. The objective of this study was to determine how longitudinal dopamine, serotonin, and oxytocin patterns in African elephants are related to ovarian cycle function. We hypothesized that dopamine concentrations are decreased, while oxytocin and serotonin are increased in non-cycling, hyperprolactinemic African elephants. Weekly urine and serum samples were collected for eight consecutive months from 28 female African elephants. Females were categorized as follows: (1) non-cycling with average prolactin concentrations of 15 ng/ml or greater (HIGH; n = 7); (2) non-cycling with average prolactin concentrations below 15 ng/ml (LOW; n = 13); and (3) cycling with normal progestagen and prolactin patterns (CYCLING; n = 8). Both oxytocin and serotonin were elevated in hyperprolactinemic elephants. Thus, we propose that stimulatory factors may play a role in the observed hyperprolactinemia in this species. Interestingly, rather than being reduced as hypothesized, urinary dopamine was elevated in hyperprolactinemic elephants compared to CYCLING and LOW prolactin groups. Despite its apparent lack of regulatory control over prolactin, this new evidence suggests that dopamine synthesis and secretion are not impaired in these elephants, and perhaps are augmented.

The adverse effects of psychotropic drugs as an endocrine disrupting chemicals on the hypothalamic-pituitary regulation in male

Adverse effects of drugs on male reproductive system can be categorized as pre-testicular, testicular, and post-testicular. Pre-testicular adverse effects disrupt the hypothalamic-pituitary-gonadal (HPG) axis, generally by interfering with endocrine function. It is known that the HPG axis has roles in the maintenance of spermatogenesis and sexual function. The hypothalamus secretes gonadotropin-releasing hormone (GnRH) which enters the hypophyseal portal system to stimulate the anterior pituitary. The anterior pituitary secretes gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) which are vital for spermatogenesis, into the blood. The FSH stimulates the Sertoli cells for the production of regulatory molecules and nutrients needed for the maintenance of spermatogenesis, while the LH stimulates the Leydig cells to produce and secrete testosterone. Many neurotransmitters influence the hypothalamic-pituitary regulation, consequently the HPG axis, and can consequently affect spermatogenesis and sexual function. Psychotropic drugs including antipsychotics, antidepressants, and mood stabilizers that all commonly modulate dopamine, serotonin, and GABA, can affect male spermatogenesis and sexual function by impairment of the hypothalamic-pituitary regulation, act like endocrine-disrupting chemicals. Otherwise, studies have shown the relationship between decreased sperm quality and psychotropic drugs treatment. Therefore, it is important to investigate the adverse reproductive effects of psychotropic drugs which are frequently used during reproductive ages in males and to determine the role of the hypothalamic-pituitary regulation axis on possible pathologies.

Update on Comparative Biology of Elephants: Factors Affecting Reproduction, Health and Welfare

Asian (Elephas maximus) and African (Loxodonta africana) elephants serve as important keystone, umbrella and flagship species. Despite that, population numbers are declining, due mainly to poaching and habitat destruction. Understanding reproductive mechanisms is vital to effective management, particularly insurance populations in captivity, and to that end, long-term biological databases are key to understanding how intrinsic and extrinsic factors affect reproductive function at individual and population levels. Through decades of hormonal and ultrasonographic monitoring, many unique aspects of zoo elephant reproduction have been identified, including differences in luteal steroidogenic activity, follicular maturation, pituitary gonadotropin secretion, fetal development and reproductive tract anatomy. Reproductive problems also hamper captive propagation efforts, particularly those related to abnormal or lack of ovarian cyclicity. Recent large-scale, multi-institutional studies and use of epidemiological approaches have identified factors important for good welfare and reproduction, which include enrichment, feeding diversity, good elephant-keeper relations, social compatibility, exercise, and not being obese. There are notable differences in reproductive mechanisms between Asian and African elephants, as well as the factors that influence reproduction and welfare, suggesting species-targeted management approaches are needed to maximize fitness. In the first edition, we discussed reproductive function in male and female elephants. Since then, a number of significant advances have been made primarily in female elephants, which will be the focus of this updated review.

Aripiprazole for the treatment of duloxetine-induced hyperprolactinemia: A case report

BACKGROUND

It is well known that aripiprazole co-treatment effectively reduces antipsychotic-induced hyperprolactinemia. However, the effectiveness of aripiprazole to treat high prolactin levels induced by antidepressant drugs with serotoninergic activity, such as duloxetine, remains unknown.

CASE PRESENTATION

An 18-year-old female diagnosed with major depressive disorder (MDD) was treated with 100 mg sertraline once daily. After two weeks, galactorrhoea was observed. Blood biochemical tests revealed an elevated serum prolactin level of 241 ng/mL. Physiological causes and additional potential pathological causes were ruled out. Therefore, sertraline was cross tapered with mirtazapine. Galactorrhoea ceased, but the side-effect of sedation prompted a switch to 40 mg duloxetine twice daily. After two weeks, the patient developed menstrual irregularities and milky discharge concomitant with a serum prolactin level of 205 ng/mL. As a result, duloxetine was decreased to 60 mg once daily, and aripiprazole was initiated at 2.5 mg daily and titrated to 5 mg daily. Two weeks after the initiation of dual therapy, galactorrhoea stopped, and prolactin levels decreased to 118 ng/mL. After eight weeks, prolactin levels decreased to 39 ng/mL, and menstruation returned to normal. After antidepressant therapy finished, prolactin levels normalized to 19 ng/mL.

CONCLUSION

The case suggests that adjunctive aripiprazole may be useful as a treatment option for duloxetine-induced hyperprolactinemia in MDD.

The forgotten effects of thyrotropin-releasing hormone: Metabolic functions and medical applications

Thyrotropin-releasing hormone (TRH) causes a variety of thyroidal and non-thyroidal effects, the best known being the feedback regulation of thyroid hormone levels. This was employed in the TRH stimulation test, which is currently little used. The role of TRH as a cancer biomarker is minor, but exaggerated responses to TSH and prolactin levels in breast cancer led to the hypothesis of a potential role for TRH in the pathogenesis of this disease. TRH is a rapidly degraded peptide with multiple targets, limiting its suitability as a biomarker and drug candidate. Although some studies reported efficacy in neural diseases (depression, spinal cord injury, amyotrophic lateral sclerosis, etc.), therapeutic use of TRH is presently restricted to spinocerebellar degenerative disease. Regulation of TRH production in the hypothalamus, patterns of expression of TRH and its receptor in the body, its role in energy metabolism and in prolactin secretion are addressed in this review.

Behavior in dogs with spontaneous hypothyroidism during treatment with levothyroxine

Background

Thyroid hormone supplementation anecdotally has been described as a valid treatment option for dogs with aggression‐related problems. However, prospective, controlled, and blinded trials evaluating behavior and neurohormonal status in hypothyroid dogs during treatment with levothyroxine are lacking.

Objective

Levothyroxine supplementation will have a significant influence on the behavior and neurohormonal status of dogs with spontaneous hypothyroidism.

Animals

Twenty client‐owned dogs diagnosed with spontaneous hypothyroidism.

Methods

This prospective study was to evaluate the behavior of dogs, which was screened at initial presentation, and after 6 weeks, and 6 months of treatment with levothyroxine (starting dosage 10 μg/kg PO q12h) using the standardized Canine Behavioral Assessment and Research Questionnaire (C‐BARQ). At each time period, circulating serotonin and prolactin (PRL) concentrations were evaluated using a commercially validated ELISA kit and heterologous radioimmunoassay, respectively.

Results

After 6 weeks of thyroid hormone supplementation, C‐BARQ scores demonstrated a significant increase in activity of hypothyroid dogs (P < .01). No significant change in any of the behavioral signs was observed after 6 months of treatment. No significant difference in circulating concentrations of serotonin (P > .99 and P = .46) and PRL (P = .99 and P = .37) were noted between the 6‐week and 6‐month periods compared with baseline.

Conclusions and Clinical Importance

The results of this study indicate increased activity of hypothyroid dogs after 6 weeks of thyroid hormone supplementation. None of the hypothyroid dogs in this cohort showed a significant change in any of the evaluated behavioral signs and neurohormonal status after 6 months of thyroid hormone supplementation.

The Impact of Psychotropic Medications on Bone Health in Youth

PURPOSE OF REVIEW

Psychotropics are prescribed to youth at rapidly growing rates and may negatively impact bone health. Little awareness exists of this association among prescribing providers. Childhood and adolescence are critical times for bone development. Understanding these effects and their management is important to informed psychotropic use.

RECENT FINDINGS

Through a variety of mechanisms, antidepressants, benzodiazepines, mood stabilizers, neuroleptics, and stimulants may all negatively impact pediatric bone health. This confers added risk of osteoporosis in a population already at high risk for suboptimal bone health. Awareness of psychotropic-mediated effects on pediatric bone development is clinically relevant to the use and monitoring of these agents. Clinicians can manage these effects through informed consent, vitamin D supplementation, lifestyle modifications, and reducing polypharmacy. For mood stabilizers, vitamin D level monitoring and secondary prevention is indicated. Future longitudinal studies and development of monitoring guidelines regarding psychotropic impact on bone health are necessary.

Dietary dopamine depletion blunts reward network sensitivity to face trustworthiness

Research demonstrating responsiveness of the neural reward network to face trustworthiness has not assessed whether the effects are mediated by dopaminergic function. We filled this gap in the literature by investigating whether dietary dopamine depletion would blunt the sensitivity of neural activation to faces varying in trustworthiness across reward regions as well as the sensitivity of behavioral responses to those faces. As prolactin release is negatively regulated by dopamine, peripheral prolactin levels confirmed the efficacy of our manipulation. The dopamine depletion manipulation moderated neural activation to face trustworthiness in the amygdala, medial orbital frontal cortex, and ventral medial prefrontal cortex. Control participants ( n=20) showed nonlinear and linear neural activation to face trustworthiness in the amygdala and ventral medial prefrontal cortex, and nonlinear activation in the medial orbital frontal cortex, while depleted participants ( n=20) showed only a linear effect in the amygdala. Controls also showed stronger amygdala activation to high trustworthy faces than depleted participants. In contrast to effects on neural activation, dopamine depletion did not blunt the sensitivity of behavioral ratings. While this is the first study to demonstrate that dopamine depletion blunts the sensitivity of the neural reward system to social stimuli, namely faces varying in trustworthiness, future research should investigate behavioral measures that may be more responsive to dopaminergic effects than face ratings. Such research would shed further light on the possibility that individual differences in dopaminergic function that were simulated by our manipulation influence social interactions with people who vary in facial trustworthiness.

Impact of NTRK2, DRD2 and ACE polymorphisms on prolactin levels in antipsychotic-treated patients with first-episode psychosis

BACKGROUND

Hyperprolactinemia is a common side-effect of antipsychotics (APs), which may trigger serious secondary problems and compromise the adherence to treatment which is crucial for prognosis, especially in patients presenting with a first-episode of psychosis (FEP).

AIMS

We evaluated, in some cases for the first time, the effect of polymorphisms in multiple candidate genes on serum prolactin (PRL) levels in an AP-treated FEP cohort recruited in the multicenter PEPs study (Phenotype - genotype and environmental interaction; Application of a predictive model in first psychotic episodes).

METHODS

PRL concentration was measured in serum from 222 patients. A total of 167 polymorphisms were selected in 23 genes. Genetic association analysis was performed in the whole sample and also in homogenous subgroups of patients treated with APs with a high (N = 101) or low risk (N = 95) of increasing PRL release, which showed significant differences in their PRL levels.

RESULTS

After Bonferroni correction, polymorphisms in NTRK2, DRD2 and ACE genes were associated with PRL concentration.

CONCLUSION

Our results give more support to the impact of DRD2, but also of other genes related to dopamine availability such as ACE. Moreover, this study provides the first evidence for the involvement of NTRK2, which suggests that pathways other than the ones related to dopamine or serotonin may participate in the AP-related PRL levels.

(±)-MDMA and its enantiomers: potential therapeutic advantages of R(-)-MDMA

The use of (±)-3,4-methylenedioxymethamphetamine ((±)-MDMA) as an adjunct to psychotherapy in the treatment of psychiatric and behavioral disorders dates back over 50 years. Only in recent years have controlled and peer-reviewed preclinical and clinical studies lent support to (±)-MDMA's hypothesized clinical utility. However, the clinical utility of (±)-MDMA is potentially mitigated by a range of demonstrated adverse effects. One potential solution could lie in the individual S(+) and R(-) enantiomers that comprise (±)-MDMA. Individual enantiomers of racemic compounds have been employed in psychiatry to improve a drug's therapeutic index. Although no research has explored the individual effects of either S(+)-MDMA or R(-)-MDMA in humans in a controlled manner, preclinical research has examined similarities and differences between the two molecules and the racemic compound. This review addresses information related to the pharmacodynamics, neurotoxicity, physiological effects, and behavioral effects of S(+)-MDMA and R(-)-MDMA that might guide preclinical and clinical research. The current preclinical evidence suggests that R(-)-MDMA may provide an improved therapeutic index, maintaining the therapeutic effects of (±)-MDMA with a reduced side effect profile, and that future investigations should investigate the therapeutic potential of R(-)-MDMA.

Depression, Antidepressant Use, and Breast Cancer Risk in Pre- and Postmenopausal Women: A Prospective Cohort Study

Background: Depression and antidepressant use is highly prevalent among U.S. women and may be related to increased breast cancer risk. However, prior studies are not in agreement regarding an increase in risk.Methods: We conducted a prospective cohort study within the Nurses' Health Study (NHS) and NHSII among females age 25 and older. Over more than 10 years of follow-up in each cohort, 4,014 incident invasive breast cancers were diagnosed. We used Cox proportional hazards regressions with updating of exposures and covariates throughout follow-up to estimate HRs and 95% confidence intervals (CIs) for associations between clinical depression and antidepressant use with invasive breast cancer risk. Analyses were repeated separately for in situ disease, as well as stratified by estrogen receptor (ER) subtype and menopausal status at diagnosis.Results: No statistically significant associations were observed between clinical depression (HR for reporting ≥3 times vs. 0, 1.13; 95% CI, 0.85-1.49) or antidepressant use (HR for reporting ≥3 times vs. 0, 0.92; 95% CI, 0.80-1.05) and invasive breast cancer risk in multivariable analyses. Likewise, we observed no significant associations between clinical depression or antidepressant use and risk of in situ, ER⁺, ER^-, premenopausal, or postmenopausal breast cancer.Conclusions: In the largest prospective study to date, we find no evidence that either depression or antidepressant use increase risk of breast cancer.Impact: The results of this study are reassuring in that neither depression nor antidepressant use appear to be related to subsequent breast cancer risk. Cancer Epidemiol Biomarkers Prev; 27(3); 306-14. ©2017 AACR.

Serotonin and Antidepressant SSRIs Inhibit Rat Neuroendocrine Dopamine Neurons: Parallel Actions in the Lactotrophic Axis

Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed for depression, but sexual side effects often compromise compliance. These reproductive dysfunctions are likely mediated by elevations of the hormone prolactin. Yet, how serotonin (5-HT) and SSRIs cause changes in prolactin secretion is not known. Here, using in vitro whole-cell patch-clamp recordings, we show that 5-HT hyperpolarizes and abolishes phasic discharge in rat neuroendocrine tuberoinfundibular dopamine (TIDA) neurons, the main inhibitor of prolactin secretion. This process is underpinned by 5-HT1A receptor-mediated activation of G-protein-coupled inwardly rectifying K(+)-like currents. We further demonstrate that the SSRIs, fluoxetine and sertraline, directly suppress TIDA neuron activity through parallel effects, independent of 5-HT transmission. This inhibition involves decreased intrinsic excitability and a slowing of TIDA network rhythms. These findings indicate that SSRIs may inhibit neuroendocrine dopamine release through both 5-HT-dependent and -independent actions, providing a mechanistic explanation for, and potential molecular targets for the amelioration of, the hyperprolactinemia and sexual dysfunction associated with these drugs.

SIGNIFICANCE STATEMENT

Depression affects approximately one-tenth of the population and is commonly treated with selective serotonin reuptake inhibitors (SSRIs; e.g., Prozac). Yet, many patients withdraw from SSRI therapy due to sexual side effects (e.g., infertility, menstrual disturbances, and impotence). Although it is generally accepted that sexual side effects are due to the ability of these drugs to elevate blood levels of the hormone prolactin, the mechanism for this hormonal imbalance is not known. Here, we show that SSRIs can inhibit hypothalamic dopamine neurons that normally suppress the secretion of prolactin. Intriguingly this inhibition can be explained both by increased serotonin activity and also by parallel serotonin-independent actions.

Dose Dependent Course of Hyperprolactinemic and Normoprolactinemic Galactorrhea Induced by Venlafaxine

Venlafaxine is a serotonergic and noradrenergic reuptake inhibitor which is used for the treatment of depression. We report a case of galactorrhea in a patient with major depressive disorder after starting treatment with venlafaxine. In particular, we discuss the course of hyper and normoprolactinemic galactorrhea. We managed this side effect initially by dose reduction and further by switching to essitalopram. Physicians should be aware of endocrinologic side effects such as galactorrhea during the serotonin and noradrenaline reuptake inhibitor treatment.

Serum Prolactin Levels in Patients with Major Depressive Disorder Receiving Selective Serotonin-Reuptake Inhibitor Monotherapy for 3 Months: A Prospective Study

OBJECTIVE

It is unclear whether selective serotonin-reuptake inhibitors (SSRIs) can significantly increase the prolactin level. The purpose of this study was to identify the relationship between the prolactin level and the administration of SSRIs such as escitalopram and sertraline. An additional purpose was to determine whether the elevation of prolactin differs between escitalopram and sertraline treatment.

METHODS

Serum prolactin levels were measured at baseline and after 3 months in 23 patients who received SSRI monotherapy with escitalopram (n=18) (ESC group) or sertraline (n=5) (SERT group) for 3 months.

RESULTS

The prevalence of hyperprolactinemia at posttreatment was 34.8% (8/23). The overall pretreatment and posttreatment prolactin levels were 21.86±20.21 and 19.89±12.03 ng/mL (mean±SD), respectively, with ranges of 6.85-86.20 and 5.19-47.61 ng/mL. The pretreatment and posttreatment prolactin levels were 20.66±15.92 and 21.97±12.33 ng/mL, respectively, in the ESC group, and 26.18±33.75 and 12.43±7.76 ng/mL in the SERT group.

CONCLUSION

Clinicians should be aware that hyperprolactinemia can appear in patients receiving escitalopram or sertraline, even though they do not need routine monitoring for prolactin levels.

Basal prolactin levels in rat plasma correlates with response to antidepressant treatment in animal model of depression

Prolactin (PRL) has been shown to be altered by psychotropic drugs, including antidepressant drugs (ADs). Many studies have focused on the response to antidepressant treatment (especially related to the serotonergic system) using the fenfluramine test (PRF), however some data suggest lack of correlation between PRF and prediction of clinical response to ADs. In our study we have investigated the hypothesis that basal plasma level of prolactin is a better predictor of antidepressant treatment. We have used Chronic Mild Stress (CMS) - the animal model of depression. Rats are exposed to CMS in combination with imipramine (IMI) treatment for 5 consecutive weeks. Blood samples were collected from the rat tail vein three times: before the CMS procedure, after 2 weeks of stress and after the complete CMS procedure (after 5 weeks of stress and IMI treatment). The PRL level in plasma was determined using the commercially available ELISA kit. In CMS, anhedonia in rats is manifested by reduced consumption of sucrose solution while administration of antidepressant drugs reverses anhedonia. Some animals (ca.30%) did not respond to antidepressant therapy and were considered treatment-resistant. There was no correlation between basal PRL levels and stress response, however, from the results obtained by Spearman Rank Correlation analysis we have observed a significant negative correlation between basal PRL levels before the CMS procedure and behavioral response to IMI administration. The obtained results indicate that the basal PRL level in rat plasma correlates with a good response to treatment in the animal model of depression.

Safety and tolerability review of lorcaserin in clinical trials

Lorcaserin is a novel selective serotonin 2C receptor agonist indicated by the US Food and Drug Administration for chronic weight management in adults with obesity or overweight with ≥1 comorbidity. The safety and efficacy of lorcaserin were established during two Phase III clinical trials in patients without diabetes (BLOOM and BLOSSOM) and one Phase III clinical trial in patients with type 2 diabetes (BLOOM-DM). Headache was the most common adverse event experienced by patients during all Phase III trials. Additional adverse events occurring in >5% of patients receiving lorcaserin included dizziness, fatigue, nausea, dry mouth and constipation in patients without diabetes, and hypoglycaemia, back pain, cough and fatigue in patients with diabetes. In a pooled analysis of echocardiographic data collected during the three lorcaserin Phase III trials, the incidence of FDA-defined valvulopathy was similar in patients taking lorcaserin and the placebo. Here, the safety profile of lorcaserin at the FDA-approved dose of 10 mg twice daily is reviewed using data from the lorcaserin Phase III programme, with a focus on theoretical adverse events commonly associated with agonists of the serotonin receptor family. Based on the lorcaserin Phase III clinical trial data, lorcaserin is safe and well tolerated in the indicated patient populations.

Serotoninergic and Circadian Systems: Driving Mammary Gland Development and Function

Since lactation is one of the most metabolically demanding states in adult female mammals, beautifully complex regulatory mechanisms are in place to time lactation to begin after birth and cease when the neonate is weaned. Lactation is regulated by numerous different homeorhetic factors, all of them tightly coordinated with the demands of milk production. Emerging evidence support that among these factors are the serotonergic and circadian clock systems. Here we review the serotoninergic and circadian clock systems and their roles in the regulation of mammary gland development and lactation physiology. We conclude by presenting our hypothesis that these two systems interact to accommodate the metabolic demands of lactation and thus adaptive changes in these systems occur to maintain mammary and systemic homeostasis through the reproductive cycles of female mammals.

Antidepressant use and circulating prolactin levels

PURPOSE

To determine whether antidepressants (AD), specifically selective serotonin reuptake inhibitors (SSRIs), are linked to elevated prolactin levels among the general population.

METHODS

Circulating prolactin levels were available for 4593 healthy participants in the Nurses' Health Study (NHS) and NHS2, including 267 AD users. We fit generalized linear models to calculate and compare adjusted mean prolactin levels between AD users and non-users and further among SSRI users. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) for "elevated" prolactin levels (>11 ng/mL) comparing AD users to non-users. We evaluated AD use and change in prolactin levels among 610 NHS participants with two measurements an average of 11 years apart.

RESULTS

Adjusted geometric mean prolactin levels were similar among SSRI users (13.2 ng/mL, 95 % CI 12.2-14.4), users of other classes of ADs (12.7 ng/mL, 95 % CI 11.0-14.6), and non-users (13.1 ng/mL, 95 % CI 12.8-13.4). Neither AD use (OR 1.17, 95 % CI 0.89-1.53) nor SSRI use (OR 0.95, 95 % CI 0.66-1.38) was associated with elevated prolactin levels. Change in prolactin levels was similar across women who started, stopped, consistently used, or never used ADs.

CONCLUSIONS

This study does not support the hypothesis that AD use would influence breast cancer risk via altered prolactin levels. These results provide some evidence that use of ADs to treat depression or other conditions may not substantially increase prolactin levels in the majority of women.

A case of galactorrhea during paroxetine treatment

Paroxetine is one of the selective serotonin reuptake inhibitor antidepressant drugs. Galactorrhea can be seen during antidepressant treatments. There are a few reports in literature on paroxetine use and related prolactin level changes. We present a case that was receiving paroxetine in whom despite low blood levels of the drug, hyperprolactinemia, and galactorrhea was found. We present a case that was receiving paroxetine despite low drug blood levels, hyperprolactinemia, and galactorrhea was found in this article.

Emerging Hyperprolactinemic Galactorrhea in Obsessive Compulsive Disorder with a Stable Dose of Fluoxetine

While fluoxetine (FXT) is a frequently prescribed selective serotonin reuptake inhibitor (SSRI), with few major side-effects; altered serotonergic transmissions in hypothalamic pathways might lead to a distressing, and often embarrassing, manifestation of galactorrhea by altering prolactin release in those on FXT. We report here a case of FXT-induced hyperprolactinemic galactorrhea developing late into treatment on a stable regimen, who responded well to subsequent replacement with sertraline. Based on present finding, we suggest that while SSRIs may share similar mechanisms of action, there exist individual differences in their effects on prolactin secretion pathways.

Amphetamine action at the cocaine- and antidepressant-sensitive serotonin transporter is modulated by αCaMKII

Serotonergic neurotransmission is terminated by reuptake of extracellular serotonin (5-HT) by the high-affinity serotonin transporter (SERT). Selective 5-HT reuptake inhibitors (SSRIs) such as fluoxetine or escitalopram inhibit SERT and are currently the principal treatment for depression and anxiety disorders. In addition, SERT is a major molecular target for psychostimulants such as cocaine and amphetamines. Amphetamine-induced transport reversal at the closely related dopamine transporter (DAT) has been shown previously to be contingent upon modulation by calmodulin kinase IIα (αCaMKII). Here, we show that not only DAT, but also SERT, is regulated by αCaMKII. Inhibition of αCaMKII activity markedly decreased amphetamine-triggered SERT-mediated substrate efflux in both cells coexpressing SERT and αCaMKII and brain tissue preparations. The interaction between SERT and αCaMKII was verified using biochemical assays and FRET analysis and colocalization of the two molecules was confirmed in primary serotonergic neurons in culture. Moreover, we found that genetic deletion of αCaMKII impaired the locomotor response of mice to 3,4-methylenedioxymethamphetamine (also known as "ecstasy") and blunted d-fenfluramine-induced prolactin release, substantiating the importance of αCaMKII modulation for amphetamine action at SERT in vivo as well. SERT-mediated substrate uptake was neither affected by inhibition of nor genetic deficiency in αCaMKII. This finding supports the concept that uptake and efflux at monoamine transporters are asymmetric processes that can be targeted separately. Ultimately, this may provide a molecular mechanism for putative drug developments to treat amphetamine addiction.

Hyperprolactinemia and medications for bipolar disorder: systematic review of a neglected issue in clinical practice

Drug-induced changes in serum prolactin (sPrl) levels constitute a relevant issue due to the potentially severe consequences on physical health of psychiatric patients such as sexual dysfunctions, osteoporosis and Prl-sensitive tumors. Several drugs have been associated to sPrl changes. Only antipsychotics have been extensively studied as sPrl-elevating agents in schizophrenia, but the extent to which bipolar disorder (BD) treatments affect sPrl levels is much less known. The objective of this systematic review is to summarize the evidence of the effects of drugs used in BD on Prl. This review followed the PRISMA statement. The MEDLINE/PubMed/Index Medicus, EMBASE, and Cochrane Library databases were systematically searched for articles in English appearing from any time to May 30, 2014. Twenty-six studies were included. These suggest that treatments for BD are less likely to be associated with Prl elevations, with valproate, quetiapine, lurasidone, mirtazapine, and bupropion reported not to change PRL levels significantly and lithium and aripiprazole to lower them in some studies. Taking into account the effects of the different classes of drugs on Prl may improve the care of BD patients requiring long-term pharmacotherapy. Based on the results of this review, lithium and valproate appear to be safer due to their low potential to elevate sPrL; among antipsychotics, quetiapine, lurasidone and aripiprazole appear to be similarly safe.

Assessing the Risks Associated with Antidepressant Use in Plastic Surgery: A Systematic Review

BACKGROUND

Antidepressant use has increased dramatically over the past decade. Although there is no question about the benefits of these medications, uncertainty exists with regard to the implications of antidepressant treatment surrounding plastic surgery. This systematic review collates all of the available literature that evaluates the risks of patient antidepressant treatment, in relation to plastic surgery.

METHODS

A comprehensive literature review of the PubMed and Cochrane databases was conducted. Articles were assessed by two independent reviewers using predefined data fields and selected using specific inclusion criteria. The two authors independently reviewed the literature and extracted data from included reviews, and discrepancies were resolved by consensus.

RESULTS

Twenty-six articles were included in the analysis and were categorized into five groups for comparison: risk of bleeding, risk of breast cancer, risk of breast cancer recurrence, breast enlargement, and miscellaneous (unique complications). Extracted information included study type, statistical analyses, conclusion, and limitations.

CONCLUSIONS

This review does not support the cessation of antidepressants in patients before plastic surgery, as the numbers needed to harm are low and the implications of withdrawal may prove to be detrimental to postoperative management. However, the use of antidepressants for mental disorders may also implicate key patient risk factors for surgical complications, and sufficient exploration into the patient's indications for the prescription is crucial. Evidence so far does not suggest that antidepressants increase the risk of breast cancer or recurrence in general, but caution should be exercised for those specifically on concurrent tamoxifen and paroxetine treatment.

TIDAL WAVES: Network mechanisms in the neuroendocrine control of prolactin release

Neuroendocrine tuberoinfundibular dopamine (TIDA) neurons tonically inhibit pituitary release of the hormone, prolactin. Through the powerful actions of prolactin in promoting lactation and maternal behaviour while suppressing sexual drive and fertility, TIDA neurons play a key role in reproduction. We summarize insights from recent in vitro studies into the membrane properties and network behaviour of TIDA neurons including the observations that TIDA neurons exhibit a robust oscillation that is synchronized between cells and depends on intact gap junction communication. Comparisons are made with phasic firing patterns in other neuronal populations. Modulators involved in the control of lactation - including serotonin, thyrotropin-releasing hormone and prolactin itself - have been shown to change the electrical behaviour of TIDA cells. We propose that TIDA discharge mode may play a central role in tuning the amount of dopamine delivered to the pituitary and hence circulating prolactin concentrations in different reproductive states and pathological conditions.

Endobiogeny: a global approach to systems biology (part 2 of 2)

ENDOBIOGENY AND THE BIOLOGY OF FUNCTIONS ARE BASED ON FOUR SCIENTIFIC CONCEPTS THAT ARE KNOWN AND GENERALLY ACCEPTED: (1) human physiology is complex and multifactorial and exhibits the properties of a system; (2) the endocrine system manages metabolism, which is the basis of the continuity of life; (3) the metabolic activity managed by the endocrine system results in the output of biomarkers that reflect the functional achievement of specific aspects of metabolism; and (4) when biomarkers are related to each other in ratios, it contextualizes one type of function relative to another to which is it linked anatomically, sequentially, chronologically, biochemically, etc.

The effects of novel and newly approved antipsychotics on serum prolactin levels: a comprehensive review

Since the 1970s, clinicians have increasingly become more familiar with hyperprolactinemia (HPRL) as a common adverse effect of antipsychotic medication, which remains the cornerstone of pharmacological treatment for patients with schizophrenia. Although treatment with second-generation antipsychotics (SGAs) as a group is, compared with use of the first-generation antipsychotics, associated with lower prolactin (PRL) plasma levels, the detailed effects on plasma PRL levels for each of these compounds in reports often remain incomplete or inaccurate. Moreover, at this moment, no review has been published about the effect of the newly approved antipsychotics asenapine, iloperidone and lurasidone on PRL levels. The objective of this review is to describe PRL physiology; PRL measurement; diagnosis, causes, consequences and mechanisms of HPRL; incidence figures of (new-onset) HPRL with SGAs and newly approved antipsychotics in adolescent and adult patients; and revisit lingering questions regarding this hormone. A literature search, using the MEDLINE database (1966-December 2013), was conducted to identify relevant publications to report on the state of the art of HPRL and to summarize the available evidence with respect to the propensity of the SGAs and the newly approved antipsychotics to elevate PRL levels. Our review shows that although HPRL usually is defined as a sustained level of PRL above the laboratory upper limit of normal, limit values show some degree of variability in clinical reports, making the interpretation and comparison of data across studies difficult. Moreover, many reports do not provide much or any data detailing the measurement of PRL. Although the highest rates of HPRL are consistently reported in association with amisulpride, risperidone and paliperidone, while aripiprazole and quetiapine have the most favorable profile with respect to this outcome, all SGAs can induce PRL elevations, especially at the beginning of treatment, and have the potential to cause new-onset HPRL. Considering the PRL-elevating propensity of the newly approved antipsychotics, evidence seems to indicate these agents have a PRL profile comparable to that of clozapine (asenapine and iloperidone), ziprasidone and olanzapine (lurasidone). PRL elevations with antipsychotic medication generally are dose dependant. However, antipsychotics having a high potential for PRL elevation (amisulpride, risperidone and paliperidone) can have a profound impact on PRL levels even at relatively low doses, while PRL levels with antipsychotics having a minimal effect on PRL, in most cases, can remain unchanged (quetiapine) or reduce (aripiprazole) over all dosages. Although tolerance and decreases in PRL values after long-term administration of PRL-elevating antipsychotics can occur, the elevations, in most cases, remain above the upper limit of normal. PRL profiles of antipsychotics in children and adolescents seem to be the same as in adults. The hyperprolactinemic effects of antipsychotic medication are mostly correlated with their affinity for dopamine D2 receptors at the level of the anterior pituitary lactotrophs (and probably other neurotransmitter mechanisms) and their blood-brain barrier penetrating capability. Even though antipsychotics are the most common cause of pharmacologically induced HPRL, recent research has shown that HPRL can be pre-existing in a substantial portion of antipsychotic-naïve patients with first-episode psychosis or at-risk mental state.

Effects of antipsychotics on bone mineral density and prolactin levels in patients with schizophrenia: a 12-month prospective study

OBJECTIVE

Effects of conventional and atypical antipsychotics on bone mineral density (BMD) and serum prolactin levels (PRL) were examined in patients with schizophrenia.

METHODS

One hundred and sixty-three first-episode inpatients with schizophrenia were recruited, to whom one of three conventional antipsychotics (perphenazine, sulpiride, and chlorpromazine) or one of three atypical antipsychotics (clozapine, quetiapine, and aripiprazole) was prescribed for 12 months as appropriate. BMD and PRL were tested before and after treatment. Same measures were conducted in 90 matched healthy controls.

RESULTS

Baseline BMD of postero-anterior L1-L4 range from 1.04 ± 0.17 to 1.42 ± 1.23, and there was no significant difference between the patients group and healthy control group. However, post-treatment BMD values in patients (ranging from 1.02 ± 0.15 to 1.23 ± 0.10) were significantly lower than that in healthy controls (ranging from 1.15 ± 0.12 to 1.42 ± 1.36). The BMD values after conventional antipsychotics were significantly lower than that after atypical antipsychotics. The PRL level after conventional antipsychotics (53.05 ± 30.25 ng/ml) was significantly higher than that after atypical antipsychotics (32.81 ± 17.42 ng/ml). Conditioned relevance analysis revealed significant negative correlations between the PRL level and the BMD values after conventional antipsychotics.

CONCLUSION

The increase of PRL might be an important risk factor leading to a high prevalence of osteoporosis in patients with schizophrenia on long-term conventional antipsychotic medication.

Serum prolactin and macroprolactin levels among outpatients with major depressive disorder following the administration of selective serotonin-reuptake inhibitors: a cross-sectional pilot study

Clinical trials evaluating the rate of short-term selective serotonin-reuptake inhibitor (SSRI)-induced hyperprolactinemia have produced conflicting results. Thus, the aim of this study was to clarify whether SSRI therapy can induce hyperprolactinemia and macroprolactinemia. Fifty-five patients with major depressive disorder (MDD) were enrolled in this study. Serum prolactin and macroprolactin levels were measured at a single time point (i.e., in a cross-sectional design). All patients had received SSRI monotherapy (escitalopram, paroxetine, or sertraline) for a mean of 14.75 months. Their mean prolactin level was 15.26 ng/ml. The prevalence of patients with hyperprolactinemia was 10.9% for 6/55, while that of patients with macroprolactinemia was 3.6% for 2/55. The mean prolactin levels were 51.36 and 10.84 ng/ml among those with hyperprolactinemia and a normal prolactin level, respectively. The prolactin level and prevalence of hyperprolactinemia did not differ significantly within each SSRI group. Correlation analysis revealed that there was no correlation between the dosage of each SSRI and prolactin level. These findings suggest that SSRI therapy can induce hyperprolactinemia in patients with MDD. Clinicians should measure and monitor serum prolactin levels, even when both SSRIs and antipsychotics are administered.

A new logical insight and putative mechanism behind fluoxetine-induced amenorrhea, hyperprolactinemia and galactorrhea in a case series

With the exception of fluoxetine, all selective serotonin reuptake inhibitors (SSRIs) commonly cause hyperprolactinemia through presynaptic mechanisms indirectly via 5-hydroxytryptamine (5-HT)-mediated inhibition of tuberoinfundibular dopaminergic neurons. However, there is little insight regarding the mechanisms by which fluoxetine causes hyperprolactinemia via the postsynaptic pathway. In this text, analysis of five spontaneously reported clinical cases of hyperprolactinemia resulting in overt symptoms of amenorrhea with or without galactorrhea, were scrupulously analyzed after meticulously correlating relevant literature and an attempt was made to explore the putative postsynaptic pathway of fluoxetine inducing hyperprolactinemia. Hypothetically, serotonin regulates prolactin release either by increasing oxytocin (OT) level via direct stimulation of vasoactitive intestinal protein (VIP) or indirectly through stimulation of GABAergic neurons. The pharmacodynamic exception and pharmacokinetic aspect of fluoxetine are highlighted to address the regulation of prolactin release via serotonergic pathway, either directly through stimulation of prolactin releasing factors (PRFs) VIP and OT via 5-HT2A receptors predominantly on PVN (neurosecretory magnocellular cell) or through induction of 5-HT1A-mediated direct and indirect GABAergic actions. Prospective molecular and pharmacogenetic studies are warranted to visualize how fluoxetine regulate neuroendocrine system and cause adverse consequences, which in turn may explore new ways of approach of drug development by targeting the respective metabolic pathways to mitigate these adverse impacts.

Selective serotonin 2A receptor antagonism attenuates the effects of amphetamine on arousal and dopamine overflow in non-human primates

The objective of the present study was to further elucidate the mechanisms involved in the wake-promoting effects of psychomotor stimulants. Many previous studies have tightly linked the effects of stimulants to dopamine neurotransmission, and some studies indicate that serotonin 2A receptors modulate these effects. However, the role of dopamine in arousal is controversial, most notably because dopamine neurons do not change firing rates across arousal states. In the present study, we examined the wake-promoting effects of the dopamine-releaser amphetamine using non-invasive telemetric monitoring. These effects were evaluated in rhesus monkeys as a laboratory animal model with high translational relevance for human disorders of sleep and arousal. To evaluate the role of dopamine in the wake-promoting effects of amphetamine, we used in vivo microdialysis targeting the caudate nucleus, as this approach provides clearly interpretable measures of presynaptic dopamine release. This is beneficial in the present context because some of the inconsistencies between previous studies examining the role of dopamine in arousal may be related to differences between postsynaptic dopamine receptors. We found that amphetamine significantly and dose-dependently increased arousal at doses that engendered higher extracellular dopamine levels. Moreover, antagonism of serotonin 2A receptors attenuated the effects of amphetamine on both wakefulness and dopamine overflow. These findings further elucidate the role of dopamine and serotonin 2A receptors in arousal, and they suggest that increased dopamine neurotransmission may be necessary for the wake-promoting effects of amphetamine, and possibly other stimulants.

Sertraline-induced galactorrhea: case report and review of cases reported with other SSRIs

There is limited literature reporting galactorrhea with antidepressants including selective serotonin reuptake inhibitors (SSRIs). In this case report, I present a case of a young female who developed galactorrhea with sertraline, which improved on discontinuation of sertraline. Computer-assisted searches on galactorrhea with SSRIs yielded 23 cases, mostly with escitalopram and paroxetine and rarely with fluoxetine, fluvoxamine and sertraline, and it may be much more frequent than recognized.

[Effect of SSRIs on bone metabolism]

INTRODUCTION

SSRIs have been shown to affect bone health in adults, but this has been poorly studied in children. Given the frequency of SSRI prescription in children and adolescents, it is crucial to evaluate the impact of SSRIs on bone growth because the bone mass attained early in life is the most important predictor of a normal bone constitution. Experimental studies have demonstrated a direct functional role of serotonin in bone metabolism, independently of hyperprolactinemia or growth hormone levels. We have reviewed the literature on serotonin and bone metabolism, including experimental studies, clinical studies in adults as well as in the pediatric population.

EXPERIMENTAL STUDIES

Experimental studies have shown that 5-HT transporter (5-HTT) is expressed in all kind of bone cells and is highly specific of the 5-HT recapture. 5-HTT inhibition by the SSRIs in these cells affects their function in vitro. Even though a few studies have suggested exposure to SSRIs could be beneficial by an anabolic effect on the trabecular bone, more concluding studies have demonstrated that SSRIs negatively affect bone growth, resulting in a specific bone phenotype including a reduction in bone mass, an altered bone architecture, and decreased mechanical properties. This phenotype is most probably the consequence of a decrease in bone formation, rather than an increase in bone resorption and is a direct and dose-dependent effect. However, many aspects of this bone effect of 5-HTT inhibition need to be further clarified, including the signal ways for 5-HTT and 5-HT receptors, origins of 5-HT in bone, and methods to isolate the inhibitory effect of 5-HTT specifically on bone.

CLINICAL STUDIES

Metabolic and neuroendocrine side effects have been documented in children and adolescents taking SSRIs but the specific and direct effect of these molecules on bone metabolism has been poorly studied in this population. In adults, clinical studies have shown an association between the use of SSRIs and bone demineralization as well as reduction in bone mass, especially in the elderly and post-menopausal women. However, depression itself has been associated with a lower bone mass and increased risk of osteoporosis. In children, case reports show a decrease in growth due to a decreased secretion of growth hormone, but not by a direct effect. One cross-sectional study suggests a decrease in bone mass following SSRI treatment that is independent of variation in prolactin levels, but without elevation of fracture risk. These results, however, need to be replicated in further studies.

CONCLUSION

Our review shows that experimental studies have demonstrated the implication of the serotonin system in bone metabolism. Mice with genetic disruption of 5-HTT have a bone phenotype of decreased bone mass, altered architecture, and decreased mechanical properties. Clinical studies exploring the effect of SSRIs on bone metabolism are scarce in children. However, results in adults tend to show a deleterious effect in the elderly. Regarding the frequency of SSRI prescription in the pediatric population, it is becoming urgent to better explore the effect of SSRIs on bone growth of children, as it can have major implications on the ulterior follow-up and on the precautions to take.

Drug-induced hypo- and hyperprolactinemia: mechanisms, clinical and therapeutic consequences

INTRODUCTION

The altered profiles of prolactin secretion in the anterior hypophysis, generated by pathological, pharmacological or toxicological causes, have special consequences on multiple functions in both genders.

AREAS COVERED

This selective review presents the main mechanisms controlling prolactin secretion, focusing on the interplay of various neurotransmitters or xenobiotics, but also on the role of psychic or posttraumatic stress. A detailed analysis of several pharmacotherapeutic groups with hyperprolactinemic effects emphasize on the relevance of the pharmacokinetic/pharmacodynamic mechanisms and the clinical significance of the long term administration.

EXPERT OPINION

Accurate monitoring and evaluation of the hyperprolactinemia induced by xenobiotics is strongly recommended. The typical antipsychotics and some of the atypical agents (amisulpride, risperidone, paliperidone), as well as some antidepressants, antihypertensives and prokinetics, are the most important groups inducing hyperprolactinemia. The hyperprolactinemic effects are correlated with their affinity for dopamine D2 receptors, their blood-brain barrier penetration and, implicitly, the requested dose for adequate occupancy of cerebral D2 receptors. Consequently, integration of available pharmacokinetic and pharmacodynamic data supports the idea of therapeutic switch to non-hyperprolactinemic agents (especially aripiprazole) or their association, for an optimal management of antipsychotic-induced hyperprolactinemia. Possible alternative strategies for counteracting the xenobiotics-induced hyperprolactinemia are also mentioned.

Iron deficiency in pediatric patients in long-term risperidone treatment

OBJECTIVE

Atypical antipsychotics, increasingly used in children and adolescents, modulate brain dopamine. Iron plays a critical role in dopaminergic signaling. Therefore, we explored whether body iron status is related to psychiatric symptom severity, treatment response, and tolerability following extended antipsychotic therapy.

METHODS

Between November 2005 and August 2009, medically healthy 7-17-year-old risperidone-treated participants enrolled in a cross-sectional study examining the long-term safety of this antipsychotic. Anthropometric measurements were obtained. Psychiatric symptom severity and dietary intake were assessed. Serum ferritin, transferrin receptor, and prolactin concentrations were measured. Linear multivariable regression analysis tested the association among body iron, symptom severity, the dose of risperidone and psychostimulants, and serum prolactin concentration.

RESULTS

The sample consisted of 115 patients (87% males) with a mean (±SD) age of 11.6 (±2.8) years. The majority had externalizing disorders, and they had taken risperidone for 2.4 (±1.7) years. Body iron was low, with 45% having iron depletion and 14% having iron deficiency. Iron status was inversely associated with weight gain during risperidone treatment and with interleukin-6. Body iron was neither associated with psychiatric symptom severity nor with the daily dose of risperidone and psychostimulants. It was, however, inversely associated with prolactin concentration, which was nearly 50% higher in the iron-deficient group.

CONCLUSIONS

Iron depletion and deficiency are prevalent in children and adolescents chronically treated with risperidone. Iron deficiency accentuates the antipsychotic-induced elevation in prolactin. Future studies should confirm this finding and investigate the potential benefit of iron supplementation in antipsychotic-treated patients.

The 5-HT deficiency theory of depression: perspectives from a naturalistic 5-HT deficiency model, the tryptophan hydroxylase 2Arg439His knockin mouse

A decreased level of brain 5-hydroxytryptamine (5-HT) has been theorized to be a core pathogenic factor in depression for half a century. The theory arose from clinical observations that drugs enhancing extracellular levels of 5-HT (5-HT(Ext)) have antidepressant effects in many patients. However, whether such drugs indeed correct a primary deficit remains unresolved. Still, a number of anomalies in putative biomarkers of central 5-HT function have been repeatedly reported in depression patients over the past 40 years, collectively indicating that 5-HT deficiency could be present in depression, particularly in severely ill and/or suicidal patients. This body of literature on putative 5-HT biomarker anomalies and depression has recently been corroborated by data demonstrating that such anomalies indeed occur consequent to severely reduced 5-HT(Ext) levels in a mouse model of naturalistic 5-HT deficiency, the tryptophan hydroxylase 2 His(439) knockin (Tph2KI) mouse. In this review, we will critically assess the evidence for 5-HT deficiency in depression and the possible role of polymorphisms in the Tph2 gene as a causal factor in 5-HT deficiency, the latter investigated from a clinical as well as preclinical angle.

Selective Serotonin Reuptake Inhibitor (SSRI) Antidepressants, Prolactin and Breast Cancer

Selective serotonin reuptake inhibitors (SSRIs) are a widely prescribed class of antidepressants. Laboratory and epidemiologic evidence suggests that a prolactin-mediated mechanism secondary to increased serotonin levels at neuronal synapses could lead to a potentially carcinogenic effect of SSRIs. In this population-based case-control study, we evaluated the association between SSRI use and breast cancer risk as a function of their relative degree of inhibition of serotonin reuptake as a proxy for their impact on prolactin levels. Cases were 2,129 women with primary invasive breast cancer diagnosed from 2003 to 2007, and controls were 21,297 women randomly selected from the population registry. Detailed information for each SSRI prescription dispensed was compiled using the Saskatchewan prescription database. Logistic regression was used to evaluate the impact of use of high and lower inhibitors of serotonin reuptake and duration of use, as well as to assess the effect of individual high inhibitors on the risk of breast cancer. Exclusive users of high or lower inhibitors of serotonin reuptake were not at increased risk for breast cancer compared with non-users of SSRIs (OR = 1.01, CI = 0.88–1.17 and OR = 0.91, CI = 0.67–1.25 respectively), regardless of their duration of use or menopausal status. While we cannot rule out the possibility of a clinically important risk increase (OR = 1.83, CI = 0.99–3.40) for long-term users of sertraline (≥24 prescriptions), given the small number of exposed cases (n = 12), the borderline statistical significance, and the wide confidence interval, these results need to be interpreted cautiously. In this large population-based case-control study, we found no conclusive evidence of breast cancer risk associated with the use of SSRIs even after assessing the degree of serotonin reuptake inhibition and duration of use. Our results do not support the serotonin-mediated pathway for the prolactin-breast cancer hypothesis.