Neuroendocrine effects of psychotropic drugs

A case of galactorrhea associated with excitalopram

Escitalopram is one of the most popular selective serotonin reuptake inhibitors (SSRIs) in current use as a first-line treatment for depression. Escitalopram is well-tolerated and rarely associated with serious side effects. Endocrine and reproductive side effects of serotonergic antidepressants are uncommon and galactorrhea is very rarely mentioned among SSRI-related side effects. Serotonin-enhancing antidepressants may result in a rise in prolactin levels through suppression of dopamine neurotransmission. In the present study, we report a case of hyperprolactinemic galactorrhea associated with escitalopram. A 36-year-old woman developed galactorrhea after initiation of escitalopram for depression and was found to have an elevated prolactin level. Escitalopram was discontinued with resolution of the patient's galactorrhea and normalization of her prolactin level.

Antipsychotic-induced hyperprolactinaemia: mechanisms, clinical features and management

Hyperprolactinaemia is an important but neglected adverse effect of antipsychotic medication. It occurs frequently with conventional antipsychotics and some atypical antipsychotics (risperidone and amisulpride) but is rare with other atypical antipsychotics (aripiprazole, clozapine, olanzapine, quetiapine, ziprasidone). For this reason the terms 'prolactin-sparing' and 'prolactin-raising' are more useful than 'atypical' and 'conventional' when considering the effect of antipsychotic drugs on serum prolactin. During antipsychotic treatment prolactin levels can rise 10-fold or more above pretreatment values. In a recent study approximately 60% of women and 40% of men treated with a prolactin-raising antipsychotic had a prolactin level above the upper limit of the normal range. The distinction between asymptomatic and symptomatic hyperprolactinaemia is important but is often not made in the literature. Some symptoms of hyperprolactinaemia result from a direct effect of prolactin on target tissues but others result from hypogonadism caused by prolactin disrupting the normal functioning of the hypothalamic-pituitary-gonadal axis. Symptoms of hyperprolactinaemia include gynaecomastia, galactorrhoea, sexual dysfunction, infertility, oligomenorrhoea and amenorrhoea. These symptoms are little researched in psychiatric patients. Existing data suggest that they are common but that clinicians underestimate their prevalence. For example, well conducted studies of women treated with conventional antipsychotics have reported prevalence rates of approximately 45% for oligomenorrhoea/amenorrhoea and 19% for galactorrhoea. An illness-related under-function of the hypothalamic-pituitary-gonadal axis in female patients with schizophrenia may also contribute to menstrual irregularities. Long-term consequences of antipsychotic-related hypogonadism require further research but are likely and include premature bone loss in men and women. There are conflicting data on whether hyperprolactinaemia is associated with an increased risk of breast cancer in women. In patients prescribed antipsychotics who have biochemically confirmed hyperprolactinaemia it is important to exclude other causes of prolactin elevation, in particular tumours in the hypothalamic-pituitary area. If a patient has been amenorrhoeic for 1 year or more, investigations should include bone mineral density measurements. Management should be tailored to the individual patient. Options include reducing the dose of the antipsychotic, switching to a prolactin-sparing agent, prescribing a dopamine receptor agonist and prescribing estrogen replacement in hypoestrogenic female patients. The efficacy and risks of the last two treatment options have not been systematically examined. Antipsychotic-induced hyperprolactinaemia should become a focus of interest in the drug treatment of psychiatric patients, particularly given the recent introduction of prolactin-sparing antipsychotics. Appropriate investigations and effective management should reduce the burden of adverse effects and prevent long-term consequences.

Antipsychotic-induced hyperprolactinaemia in women: pathophysiology, severity and consequences. Selective literature review

BACKGROUND

Hyperprolactinaemia has for decades been an inevitable and neglected side-effect of antipsychotic medication. The recent introduction of prolactin-sparing antipsychotic agents makes a re-examination of this problem timely.

AIMS

To review the literature on antipsychotic-induced hyperprolactinaemia and its consequences.

METHOD

A search was made of the Medline database (1966-2002) for key articles, supplemented by cross-referencing.

RESULTS

During antipsychotic treatment prolactin concentrations can rise to ten times normal levels or above, and existing data indicate that 17-78% of female patients have amenorrhoea with or without galactorrhoea. Survey data, however, suggest that clinicians underestimate the prevalence of these conditions. Long-term consequences of antipsychotic-related hypo-oestrogenism require further research but are likely to include premature bone loss.

CONCLUSIONS

Antipsychotic-induced hyperprolactinaemia should become a focus of interest in the drug treatment of psychiatric patients.

Serum prolactin concentration in patients taking neuroleptic drugs

OBJECTIVE

Non-tumour causes of hyperprolactinaemia, including prolactin-elevating drugs, must be excluded. There is a general view that such drugs are unlikely to raise serum PRL above 3000 mU/I, but the literature is confusing. We report 8 patients receiving treatment with neuroleptic drugs, whose serum PRL concentrations were grossly elevated.

METHODS

Prolactin was measured using a 2-site immunofluorometric assay (Abbott Laboratories; reference range < 500 mU/l). Seven of the eight women (age range 24-49 years) were symptomatic (galactorrhoea, oligo- or amenorrhoea).

RESULTS

Prolactin concentrations ranged from 3600 mU/l to 7300 mU/l. All patients had a normal pituitary CT scan. Five patients were treated with bromocriptine without detriment to their mental state.

CONCLUSION

Prolactin can rise to concentrations associated with prolactinomas in patients on neuroleptic drugs. As it is rarely possible to stop the drugs to see if the PRL concentration will decline to normal, neuroradiology is required in these patients to exclude a vision-threatening macroprolactinoma before deciding on medical treatment.

Antidepressants are not drugs of abuse or dependence

There is a view among both the lay and medical audience that antidepressants are addictive. Non-compliance may arise as a result, with fatal consequences in some cases. In spite of the fact that anti-depressants have not proved to be drugs of abuse or dependence, confusion exists in the literature, particularly regarding the definition of the terms misuse and abuse in opioid addicts. Here, antidepressants are used to treat the depressive component of the addictive syndrome and have proved effective. In some instances, however, misuse of antidepressants has been found in methadone-treated addicts, which may be due to an enhancement of the effects of methadone. These effects have led some people to believe, wrongly, that antidepressants are substances of abuse. Our findings, from a review of the literature, show that such use of antidepressants by methadone patients is by definition misuse and not abuse. Further, the known withdrawal symptoms which occasionally follow cessation of anti-depressant therapy are not, on their own, an indication of addictive potential. We therefore conclude that antidepressant drugs are not substances of abuse and dependence.