Fluoxetine-induced sexual dysfunction reversed by loratadine.

Sir: Sexual dysfunction as a side effect of antidepressant treatment occurs at a rate of roughly 50% of treated patients. Fluoxetine is no exception. Attempts at reversing sexual side effects in selective serotonin reuptake inhibitors (SSRIs) have included dosage reduction, change to a different SSRI or nonSSRI, and adding bupropion, Ginkgo biloba, cyproheptadine, yohimbine, trazodone, and sildenafil, all with varying degrees of success. In this study, loratadine, a long-acting tricyclic antihistamine with selective peripheral histamine H1 receptor antagonistic activity, appeared to be very helpful in reversing fluoxetine-induced sexual dysfunction. About 12 months ago, one of my male clients with major depression who previously had experienced sexual dysfunction with fluoxetine, 5 mg/day, restarted taking fluoxetine, 5 mg/day, while also taking loratadine, 2.5 mg/day, for allergic rhinitis. The patient was taking these low doses because of being a slow metabolizer of medication in general. Whereas before with fluoxetine he had reported dulling of penile sensation and delayed erection and ejaculation, in the presence of loratadine none of these side effects were present and he reported normal sexual function, which continued at last report. Due to this initial success with loratadine, over the next 9 months I prescribed, with informed consent, loratadine for fluoxetine-induced sexual dysfunction in 9 additional patients (5 men and 4 women) with a diagnosis of major depression. No sexual dysfunction assessment scales were employed, just the verbal report of each patient within the confines of a typical 15minute medication review. Before-and-after reports were noted concerning level of sexual interest, delay or absence of erection, and delay or absence of orgasm. Two male patients reported delayed or absent erection and orgasm; 1 male patient reported impotence, anorgasmia, and no sexual interest; 2 male patients had anorgasmia and low sexual interest; 3 female patients reported anorgasmia and no sexual interest; and 1 female patient experienced anorgasmia only. No change in general or psychiatric medications was made. Dosage of loratadine ranged from 2.5 to 15 mg, depending on side effects and efficacy. Most patients were started on 10 mg/day. Seven of 9 patients had complete reversal of sexual dysfunction within 2 days, and the other 2 experienced significant improvement of sexual side effects. One male patient, who had partial impotence and low libido, had function restored to a prefluoxetine state by taking loratadine, 10 mg, 1 day before planned sexual activity. Side effects of loratadine ranged from none to mild-to-moderate dry mouth and sedation, which responded to bedtime dosing or reduction in dose. No change was seen on effectiveness of fluoxetine for depression, although the patients were happy to have their sexual function restored. Furthermore, a female patient taking nefazadone and sertraline responded nicely to the addition of loratadine for low sexual interest and anorgasmia. I also prescribed loratadine for low sexual interest and anorgasmia to a female patient taking paroxetine and a male patient experiencing impotence who was being treated with citalopram, but neither had a positive response. I have no explanation for this lack of efficacy. It appears from this small open study that loratadine is a promising agent for reversing fluoxetine-induced sexual dysfunction. These results are subject to the limitations of a retrospective report and the possibility of a placebo-like effect. A larger double-blind controlled study could confirm a generalization of these findings. If confirmed, these findings could prompt an investigation into the mechanism of action of loratadine in reversing sexual dysfunction in patients treated with fluoxetine and possibly lead to development of antidepressants without this side effect. Whether loratadine could be useful for sexual dysfunction induced by other SSRIs awaits further study.