Sexual Dysfunction Associated with Nefazodone

Introduction:

Antidepressants, especially the serotonin selective reuptake inhibitors, contribute to anorgasmia at rates ranging from 20 to 75% (Seagraves, 1998). Clinicians are confronted with managing this distressing side effect in a variety of manners drug substitution is one such strategy (Seagraves, 1998).

We report a case in which a patient experiencing anorgasmia from venlafaxine was switched to nefazodone due to it having very few sexual side effects (Settle, 1998) to not causing sexual side effects common to the SSRIs (Gorman, 1997).

Case report:

Ms. N, a 23 year-old married female presented to our clinic for evaluation and treatment of depression. She was diagnosed with a major depressive episode moderate in accordance with DSM IV. She was in excellent physical health, denied the use of alcohol, nicotine, illicit substances and drank one cup of tea in the morning with breakfast. At the time of evaluation her only prescription medication was oral contraceptives and an occasional ibuprofen tablet. She had been married for two years and described her marriage as stable with a satisfactory sex life. The patient agreed to a trial of venlafaxine extended release 75mg qd and noted about one week into treatment she was not able to achieve orgasm. She denied any changes in sexual practice which may have contributed and agreed to see and wait if the anorgasmia would pass as she developed tolerance to the venlafaxine. At a follow-up appointment ten days later there had been no resolution and a decision was made to taper off the venlafaxine and switch to nefazodone. The patient's dose was cut to 37.5mg per day for one week, the to 37.5mg on an every other day basis for one week. At that time she discontinued the medication entirely. During her week off venlafaxine she reported she was again able to experience full orgasm but requested an alternate agent as she didn't feel back to her baseline in terms of depression. She began treatment with nefazodone 50mg b.i.d. and noted that within five days an inability to experience orgasm. She requested a change rather than adding other medications or taking drug holidays to manage the anorgasmia. The patient agreed to a trial of citalopram 20mg qd and at six months she has not experienced any sexual dysfunction with complete stabilisation of her depression.

Discussion:

While the exact mechanism of sexual dysfunction associated with antidepressants especially the SSRIs is not fully understood their influences on the serotonin system may be responsible (Seagraves,1998). With our patient it is not understood why she experienced anorgasmia while taking nefazodone. Initially we thought it due to the influence from the venlafaxine however she returned to her baseline following its discontinuation prior to initiating nefazodone. What is also curious is that she did not experience sexual dysfunction while taking citalopram,an SSRI. This speaks to the complexity of human sexual behaviour and the numerous neurotransmitter systems involved. Until the complexities are more fully understood clinicians must be aware that all psychotropic medications may contribute to sexual dysfunction given the effects these medication have on neurotransmitters and their respective balances within the central nervous system.

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