The Sexual Side-Effects of Antipsychotics

Written by Martina Hummer and Johannes Huber.

Neuroleptics or antipsychotics are prescribed for Bipolar Disorder and Schizophrenia. They are used to treat a variety of psychiatric problems, such as preoccupation with troublesome and recurring thoughts, overactivity, and unpleasant and unusual experiences such as hearing and seeing things not normally seen or heard.

Some of the benefits of these antipsychotics may occur in the first few days, but it is not unusual for it to take several weeks or months to see the full benefits. In contrast, many of the side effects are worse when you first start taking it.

Antipsychotics, Prolactin and Sexual Side Effects

Antipsychotics can cause a raising of the body's level of a hormone called prolactin. In women, this can lead to an increase in breast size and irregular periods. In men, it can lead to impotence and the development of breasts. Most of the typical antipsychotic drugs, risperidone (Risperidal) and amisulpride have the worst effect.

The best known function of prolactin is the stimulation and maintenance of lactation, but it has also been found to be involved in over 300 separate functions including involvement in water and electrolyte balance, growth and development, endocrinology and metabolism, brain and behavior, reproduction and immunoregulation.

In humans, prolactin is also thought to play a role in the regulation of sexual activity and behavior. It has been observed that orgasms cause a large and sustained (60 min) increase in plasma prolactin in both men and women, which is associated with decreased sexual arousal and function. Furthermore, increased prolactin is thought to promote behaviors that encourage long-term partnership.

Studies of patients who are treatment-naive or who have been withdrawn from treatment for a period of time indicate that schizophrenia per se does not affect prolactin concentrations.

Sexual Problems Among Worst Side Effects

Patients with Schizophrenia and Bipolar Disorder consider sexual dysfunction to be among the most important side effects. Sexual dysfunction includes low sexual desire, difficulty maintaining an erection (for men), difficulty achieving orgasm.

(If you have any of these symptoms and they are causing you concern, contact your doctor. He/she may be able to reduce your dose or change your medication.)

These adverse antipsychotic sexual side effects can have a serious negative impact on the patient in terms of causing distress, impairing quality of life, contributing to stigma, and on acceptance of treatment. In fact, many discontinue treatment because of the sexual side effects.

Effects of Antipsychotics on Prolactin and Sexual Health

The effects of conventional antipsychotics on prolactin are well known. Over 25 years ago, the sustained elevation of serum prolactin to pathological levels by conventional antipsychotics was demonstrated by Meltzer and Fang. The most important factor regulating prolactin is the inhibitory control exerted by dopamine. Any agent that blocks dopamine receptors in a non-selective manner can cause elevation of serum prolactin. Most studies have shown that conventional antipsychotics are associated with a two-to ten-fold increase in prolactin levels.

Prolactin is a hormone in the blood that helps to produce milk and is involved in breast development. However, increased prolactin can lead to a decrease in libido when it is not needed.

The increase in prolactin that occurs through the use of conventional antipsychotics develops over the first week of treatment and remains elevated throughout the period of use. Once treatment stops, prolactin levels return to normal within 2-3 weeks.

In general, second-generation atypical antipsychotics produce lower increases in prolactin than conventional agents. Some agents, including olanzapine (Zyprexa), quetiapine (Seroquel), ziprasidone (Geodon) and clozapine (Clozaril) have been shown to produce no significant or sustained increase in prolactin in adult patients. However, in adolescents (age 9-19 years) treated for childhood-onset schizophrenia or psychotic disorder, it has been shown that after 6 weeks of olanzapine treatment prolactin levels were increased beyond the upper limit of the normal range in 70% of patients.

Second-generation antipsychotics that have been associated with increases in prolactin levels are amisulpride, zotepine and risperidone (Risperidal).

The most common clinical effects of hyperprolactinaemia (high prolactin levels) are:

In Women:

• anovulation
• infertility
• amenorrhoea (loss of period)
• decreased libido
• gynaecomastia (swollen breasts)
• galactorrhoea (abnormal breast milk production)

In Men:

• decreased libido
• erectile or ejaculatory dysfunction
• azoospermia (no sperm are present in the ejaculate)
• gynaecomastia (swollen breasts)
• galactorrhoea (occasionally) (abnormal breast milk production)

Less frequently, hirsutism (excessive hairiness) in women, and weight gain have been reported.