Do SSRIs Cause Night Sweats?
Yes, SSRIs commonly cause night sweats (nocturnal hyperhidrosis), with approximately 63% of patients on second-generation antidepressants experiencing sweating as an adverse effect 1.
Evidence for SSRI-Induced Sweating
The relationship between SSRIs and hyperhidrosis is well-established in clinical guidelines and research:
Sweating is listed among the most common adverse effects of second-generation antidepressants, alongside diarrhea, dizziness, dry mouth, fatigue, headache, sexual dysfunction, tremor, and weight gain 1.
A comprehensive meta-analysis of 76 trials involving 28,544 subjects found that SSRIs increase the risk of hyperhidrosis nearly 3-fold compared to placebo (RR = 2.93,95% CI: 2.46-3.47) 2. This effect was consistent across most SSRIs, with notable exceptions being fluvoxamine, bupropion, and vortioxetine, which did not show significantly increased sweating risk.
The sweating risk does not appear to be dose-dependent for SSRI/SNRI medications 2, meaning that lowering the dose may not reliably reduce this side effect.
Mechanism of SSRI-Induced Sweating
The mechanism involves both central and peripheral effects:
Central thermoregulatory disruption: SSRIs act at the hypothalamus and spinal thermoregulatory centers, altering the body's temperature regulation 3. The increased serotonergic activity in these centers appears to trigger inappropriate sweating responses.
Dopamine transporter affinity: Interestingly, the meta-analysis found that increased risk of hyperhidrosis was specifically associated with increased affinity of SSRI/SNRI medications to the dopamine transporter 2, suggesting a more complex mechanism than pure serotonergic effects alone.
Acetylcholine is the principal neuroeccrine mediator at sweat glands 3, but SSRIs appear to influence sweating through upstream central mechanisms rather than direct effects on the eccrine-neuroeffector junction.
Clinical Management Options
When SSRI-induced sweating becomes problematic:
Switch to a different antidepressant: Consider fluvoxamine, bupropion, or vortioxetine, which showed no significant increase in hyperhidrosis risk 2.
Add mirtazapine: Case reports demonstrate dose-dependent reduction of SSRI-induced sweating when mirtazapine is added, likely due to its serotonin antagonistic properties at certain receptor subtypes 4.
Add terazosin: A randomized controlled trial showed that terazosin 1 mg significantly reduced sweating severity in patients taking sertraline, with 68% of patients improving to the lowest grade of sweating versus only 6% with placebo 5. This works by blocking adrenergic nervous system involvement in sweat secretion.
Drug discontinuation or dose reduction remains an option 3, though dose reduction may be less effective given the lack of dose-response relationship 2.
Important Caveats
While sweating is common, it rarely leads to treatment discontinuation—nausea and vomiting are the most common reasons patients stop SSRIs 1.
The symptom can significantly impact quality of life and cause patient discomfort and embarrassment 3.
SNRIs show similar rates of hyperhidrosis (RR = 3.17) compared to SSRIs (RR = 2.93), with no statistically significant difference between these classes 2.