Are Sexual Side Effects of Prolactin-raising Antipsychotics Reducible to Serum Prolactin?

Objective: To assess the degree to which sexual side effects (SSE) are associated with prolactin-raising antipsychotics, and to what degree such SSE are reducible to serum prolactin levels.

Method: A large sample (n=264) of patients treated for 6 weeks with prolactin-raising and prolactin-sparing antipsychotics was assessed for changes in sexual performance in terms of libido, arousal and orgasm using the Antipsychotics and Sexual Functioning Questionnaire. For men also erection and ejaculation were evaluated. At 6 weeks, prolactin levels were assessed and analyzed in relation to sexual performance.

Results: Men and women reported SSE (libido and orgasm) with about the same frequency. Prolactin-raising medication induced significantly more SSE than prolactin-sparing medication (adjusted OR=3.4, 95% CI: 1.8, 6.5) with 43% of emerging SSE attributable to prolactin-raising medication. When adjusted for serum prolactin, the association between prolactin-raising medication and SSE was reduced but remained significant (OR=2.1, 95% CI: 1.0, 4.5); 27% of emerging SSE remained attributable to prolactin-raising medication. For erectile and ejaculatory dysfunction in men, the attributable fraction due to prolactin-raising medication was 32% before, and 11% after adjustment for serum prolactin.

Conclusions: Around 40% of emerging SSE in schizophrenia are attributable to the prolactin-raising properties of antipsychotic medication. Of this attributable fraction, around one-third to two-thirds is directly reducible to the effects of serum prolactin.