Altered prolactin response to clomipramine rechallenge in healthy subjects

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.

Specific effects of escitalopram on neuroendocrine response

PURPOSE

Citalopram, a selective serotonin reuptake inhibitor, is used as a neuroendocrine probe in human subjects to assess serotonin function as reflected in prolactin and plasma cortisol release. Citalopram is a racemic mixture of equal proportions of the S(+) and R(-) enantiomers. Inhibition of serotonin reuptake and, consequently, antidepressant activity is associated, almost exclusively, with the S(+) enantiomer ("escitalopram"). Studies in animal models indicate that the presence of the R(-) isomer may interfere with the serotonin reuptake activity of escitalopram. The current study compared the neuroendocrine effects of citalopram and escitalopram in healthy human volunteers.

METHODS

Plasma cortisol and prolactin levels following a single oral dose of citalopram (40 mg) or escitalopram (20 mg) were compared in samples taken every 15-30 min over a period of 240 min. Plasma citalopram concentration was determined at the same intervals.

RESULTS

Escitalopram and citalopram caused equivalent increases in plasma cortisol and prolactin. The administration of dexamethasone prior to the escitalopram challenge blocked the evoked increase in cortisol.

CONCLUSION

This is the first study to prove that a single dose of escitalopram acts centrally and not peripherally, providing further support of the use of oral escitalopram as a probe for brain serotonergic function.

Effects of oral racemic citalopram on neuroendocrine responses

Citalopram, a selective serotonin reuptake inhibitor (SSRI), has been used as a neuroendocrine probe to assess serotonin (5-HT) function in human subjects. In an effort to characterize the oral citalopram challenge, we hypothesized that oral racemic citalopram would increase plasma cortisol, prolactin and adrenocorticotropic hormone (ACTH) concentrations; ACTH had not been measured in previous studies on the neuroendocrine effects of citalopram. Nine healthy male subjects initially received 20 mg of citalopram in an open-label study, and subsequently received placebo and 40 mg of citalopram in a single-blind, randomized, cross-over study. The administration of citalopram 20 mg failed to produce a significant neuroendocrine response but 40 mg resulted in reliably increased plasma cortisol concentrations. The 40 mg dose, however, did not reliably influence the levels of plasma prolactin or plasma ACTH. The results of this study indicate that caution should be used in accepting oral racemic citalopram as a potential presynaptic serotonergic challenge agent. Further studies are needed to fully determine the validity of racemic citalopram and the active enantiomer, escitalopram, as 5-HT probes.

L-5-Hydroxytryptophan augments the neuroendocrine response to a SSRI

The objective of the study was to assess l-5-hydroxytryptophan's (l-5HTP) augmentation effect on the neuroendocrine response to a SSRI (citalopram). A neuroendocrine challenge study was conducted in healthy Asian male subjects. The neuroendocrine response to oral citalopram and l-5HTP was measured primarily as the prolactin and cortisol area under the response curve (or AUC). The study comprised 2 studies: Study 1. A double blind, randomised dose ranging study was conducted with l-5HTP (50-200 mg) to explore the prolactin and/or cortisol dose response and select a dose that provided a threshold neuroendocrine response. Study 2. A randomized comparison of citalopram 20 vs 40 mg was used to assess the effect of these doses on prolactin and cortisol. Based on the results of the dose response assessments with l-5HTP and cortisol, 200 mg l-5HTP was subsequently used in Study 2 to explore the augmentation of the neuroendocrine response to 20 mg citalopram. Citalopram, but not l-5HTP, increased prolactin AUC(0-3h) while 5HTP and citalopram increased cortisol AUC(0-3h). A 200 mg dose of l-5HTP significantly augmented the prolactin and cortisol response AUC(0-3h) to 20mg oral citalopram. The results of the study suggest that an augmented neuroendocrine challenge may be a suitable marker to demonstrate increased 5-HT-mediated responses when exploring novel agents as improved SSRIs.

Neuroendocrine predictors of response to intravenous clomipramine therapy for refractory obsessive-compulsive disorder

The current study examines the neuroendocrine response to intravenous clomipramine (IV CMI) in oral CMI-resistant obsessive-compulsive disorder (OCD) patients on day 1 and day 14 of treatment to identify predictors of response. Forty-four OCD patients with an inadequate response or poorly tolerant to oral CMI were begun at 25 mg IV CMI, increasing to 250 mg by day 10, and continuing on that dose to day 14. On day 1, plasma levels of prolactin (PRL), growth hormone (GH), and cortisol were obtained immediately before the 25 mg IV infusion, and at five 30-minute time points after the infusion. On day 14, hormonal samples were obtained in a similar fashion. Response was assessed by the Clinical Global Impressions (CGI). Low PRL(MAX) to IV CMI and low cortisol levels overall on day 1 were both significantly associated with clinical response at day 14. An overall increase in growth hormone (GH) secretion during the day 14 testing was associated with positive response. A pronounced PRL response to IV CMI on day 14 was exhibited by the nonresponders, whereas a smaller and later but significant increase in PRL was noted in the responders. The findings suggest that in this sample of oral CMI-resistant patients with OCD, neuroendocrine measures derived from pharmacological challenge with IV CMI are capable of distinguishing IV CMI treatment responders from nonresponders. The limitations of IV CMI as a specific probe of serotonin function are discussed.

The citalopram challenge test in patients with major depression and in healthy controls

Neuroendocrine challenge tests in depressed patients have revealed a blunted hormonal reaction to serotonergic stimuli. In the present study, citalopram was chosen as the serotonergic agent for neuroendocrine stimulation. Compared to earlier challenge agents, citalopram has the advantage of serotonergic selectivity, its application is well tolerated and the possibility of intravenous application reduces pharmacokinetic interference. Sixteen patients suffering from an acute episode of major depression and 16 healthy controls underwent the stimulation procedure with 20 mg of citalopram and placebo. Whereas significant differences in the secretion of prolactin and cortisol between citalopram and placebo challenge were observed in the control group, no differences were found in the group of depressed patients. Comparison of depressed patients and controls showed a significantly blunted prolactin secretion in patients. Differences in cortisol secretion following serotonergic stimulation with citalopram did not become significant. The stimulation procedure was well tolerated in all subjects, although a higher number of side effects was observed in the control group. The amount of side effects did not correlate with the hormone responses. These results are in line with the hypothesis of serotonergic hypofunction in depressed patients. In conclusion, the 20-mg citalopram challenge test is thought to be a promising tool for further investigation of serotonergic function in psychiatric illness.

Parenteral clomipramine challenge in depressed adolescents: mood and neuroendocrine response

BACKGROUND

Major depressive disorder (MDD) in the adolescent demonstrates a unique clinical profile, and pathogenic serotonergic dysregulation is hypothesized. Parenteral clomipramine (CMI) is known to distinguish adult MDD from control, but neurochallenge data are lacking in adolescent MDD.

METHODS

Thirteen drug-free outpatient adolescents who met DSM-III-R criteria for MDD were compared to adolescent controls by acute neuroendocrine and mood response to 12.5 mg of parenteral CMI.

RESULTS

Repeated measures analysis revealed significant changes from baseline for sadness (p < .01) between groups, with normal controls increasing sadness rating after CMI. Prolactin (PRL) maximum change score from baseline was decreased in MDD relative to controls (p < .05). Gender effects on PRL were evident in controls but not in MDD.

CONCLUSIONS

The findings of PRL blunting in adolescent MDD mirrors previous work in adults. A unique finding is the induction of sadness in normal adolescent controls after CMI infusion.

Breast enlargement during chronic antidepressant therapy

Recent reports of mammoplasia during selective serotonin re-uptake inhibitor (SSRI) therapy suggested that this side effect may be more common than previously reported. We examined 59 women receiving > or = 2 months treatment with an SSRI or venlafaxine for changes in breast size in relation to menopausal status, weight gain and duration of drug therapy. Serum prolactin, estradiol and beta-hCG were also measured before and during treatment in a subgroup of patients. Twenty-three out of 59 patients (39%) reported some degree of mammoplasia. Significantly more SSRI vs. venlafaxine patients reported mammoplasia (p < 0.01). Eighty-four percent with mammoplasia had weight gain vs. 30% without mammoplasia (p < 0.001). The rate of mammoplasia was unrelated to age, menopausal status or duration of treatment. Serum prolactin increased during treatment in the paroxetine subgroup (p < 0.03). In conclusion, antidepressant-induced mammoplasia may be more common than previously expected.

Daily administration of m-chlorophenylpiperazine to healthy human volunteers rapidly attenuates many of its behavioral, hormonal, cardiovascular and temperature effects

The serotonergic agent meta-chlorophenylpiperazine (m-CPP) increases temperature and plasma ACTH and other hormones and decreases social interaction, locomotor activity and food intake in rats, most likely via stimulation of 5-HT2C receptors. Repeated daily administration of m-CPP to rats induces rapid tolerance to these effects of m-CPP. As m-CPP has been used in challenge tests and in preliminary treatment trials in humans, we evaluated the possible development of tolerance to m-CPP in ten healthy human volunteers using a double-blind, random assignment crossover study of placebo versus daily m-CPP infusions. Psychological and physical symptoms of anxiety, temperature, pupil size, diastolic blood pressure, and plasma ACTH, cortisol, and prolactin concentrations were increased by the first administration of m-CPP (0.08 mg/kg) compared to placebo. All of these responses were attenuated on m-CPP days 2 and 3. Plasma m-CPP levels did not differ across the 3 m-CPP days. Repeated m-CPP administration thus appears to induce rapid tolerance to its behavioral and physiological effects in humans. Further investigations of the mechanisms involved in the development of subsensitivity to m-CPP may contribute to increased understanding of the regulation of serotonin-mediated functions and of anxiety disorders.

Hormonal responses to meta-chlorophenylpiperazine (m-CPP) are undiminished by acute m-CPP pretreatment

Two challenges with meta-chlorophenylpiperazine (m-CPP, 0.5 mg/kg, p.o.) were performed in healthy volunteers to test the short-term stability of hormonal responses. Challenges were performed in an identical fashion and were conducted on sequential days. Circulating m-CPP plasma levels, as well as prolactin and cortisol responses to m-CPP, were correspondingly similar in magnitude on the 2 days. These data suggest that both prolactin and cortisol responses to single oral administrations of m-CPP are stable over at least a 24-h period.

Effects of acute intravenous clomipramine on obsessive-compulsive symptoms and response to chronic treatment

The aim of this study was to test the hypothesis that obsessive-compulsive symptoms are temporarily worsened by acute intravenous clomipramine, suggesting that there is a basal hypersensitivity of serotonin (5-HT) receptors in obsessive-compulsive (OC) patients. We also investigated the relationship of the effects of acute (intravenous) and chronic (oral) administration of clomipramine. Twenty-eight OC patients were recruited. The first part of the study included placebo and clomipramine infusions and monitoring of OC symptoms by 100 mm Visual Analogue self-rated scales (VAS). There was significant worsening of obsessions in the whole sample during clomipramine infusion. The second part included standardized 10-week oral treatments with clomipramine and evaluation of clinical efficacy. Among the 18 patients who completed the second part of the study, oral clomipramine significantly reduced OC symptoms, but OC patients who had become worse after clomipramine infusion showed higher Y-BOCS scores.