How long after starting SSRIs or SNRIs do sexual side effects usually begin?
Executive summary
Sexual side effects from selective serotonin reuptake inhibitors (SSRIs) and serotonin‑norepinephrine reuptake inhibitors (SNRIs) commonly appear very early in treatment—often within days and, according to multiple clinical and citizen‑report accounts, in some people within the first dose or 30 minutes of taking the medication—and can include reduced libido, delayed or absent orgasm, genital numbness and erectile difficulties [1] [2] [3]. For most patients these effects begin during initiation or after dose increases and resolve with dose change or discontinuation, but a smaller subset develops post‑SSRI/SNRI sexual dysfunction (PSSD) in which symptoms persist for months to years after stopping the drug [4] [5] [6].
1. How quickly do sexual side effects typically start?
Clinical reviews and patient‑level reports converge on the finding that sexual effects are often immediate or appear within the first days to weeks of treatment: some clinical observers report altered genital sensitivity within 30 minutes of the first dose for many people, while systematic studies record high rates of new sexual dysfunction early in SSRI/SNRI courses [1] [3] [7]. Randomized trials and post‑marketing data show that many patients notice decreased libido, delayed orgasm, or erectile problems within the first one to four weeks, and incidence estimates during treatment range widely but can be substantial—frequencies reported between roughly 25% and over 70% depending on the study and drug [8] [3].
2. Why does timing vary between people and drugs?
Timing and severity depend on pharmacology (some drugs, dose and kinetics), baseline sexual function, age, comorbidities, and concurrent medications, with paroxetine, citalopram and some others historically linked to higher rates of dysfunction [9] [3]. SNRIs share many serotonergic effects with SSRIs and therefore can cause similar sexual problems, though some literature suggests SNRIs may show somewhat different risk profiles; overall, side effects are generally dose‑related because they stem from serotonergic modulation of sexual circuitry [10] [11].
3. When do symptoms persist after stopping treatment?
Most sexual side effects remit after dose reduction or discontinuation, but a recognized minority develop persistent post‑treatment symptoms—PSSD—characterized by genital numbness, anorgasmia, loss of libido and erectile dysfunction that continue after drug cessation; reports date back decades and regulatory bodies and researchers now acknowledge case reports and small studies documenting persistence for months to years [5] [4] [6]. Some product labels (fluoxetine in 2011) and pharmacovigilance reviews have begun to add warnings, but broad consensus on incidence, mechanisms and prognosis remains incomplete [5] [12].
4. What does this mean for patients and prescribers?
Because sexual side effects commonly begin early, clinicians should inform patients before starting SSRIs/SNRIs and monitor sexual function within the first weeks—discussion and shared decision‑making reduces surprises and nonadherence [8] [13]. Management strategies during treatment include dose adjustment, switching to agents with lower sexual‑side‑effect risk or adding adjunctive drugs like bupropion, although there is no evidence that such strategies prevent PSSD when it occurs after stopping the serotonergic agent [9] [2].
5. Limits, controversies and the research gap
Estimates of onset and persistence vary because trials often underreport sexual harms, post‑marketing surveillance and patient advocacy have highlighted long‑term harms, and mechanisms for PSSD remain theoretical; regulatory action has been uneven [7] [2] [12]. Academic reviews call for better prospective studies, standardized measurement of sexual function from baseline through treatment and after discontinuation, and transparent labeling so patients can weigh benefits against the nontrivial and sometimes persistent risk [4] [6].