Can fluoxetine (selective serotonin reuptake inhibitor) cause sweating?

Fluoxetine and Sweating

Yes, fluoxetine commonly causes excessive sweating (diaphoresis) as a side effect. 1 This is a well-documented adverse effect that occurs with selective serotonin reuptake inhibitors (SSRIs) including fluoxetine.

Evidence for Fluoxetine-Induced Sweating

• Sweating is explicitly listed among the common adverse effects of SSRIs in multiple clinical guidelines 1
• In a 6-week randomized double-blind parallel study comparing fluoxetine with imipramine and placebo, excessive sweating was identified as one of the predominant adverse experiences reported by fluoxetine patients 2
• In a subsequent 48-week open-label extension of the same study, excessive sweating remained the predominant adverse effect in the fluoxetine group 2

Mechanism of SSRI-Induced Sweating

The mechanism appears to involve serotonergic and noradrenergic pathways:

• Peripherally, sweating is regulated noradrenergically by the sympathetic nervous system 3
• Central noradrenergic signal transmission is influenced by serotonin (5-HT) 3
• SSRIs like fluoxetine can affect the balance between these neurotransmitter systems, potentially leading to increased sweating 3

Prevalence and Impact

• About 63% of patients receiving second-generation antidepressants (including SSRIs) experience at least one adverse effect during treatment 1
• Sweating is specifically mentioned alongside diarrhea, dizziness, dry mouth, fatigue, headache, sexual dysfunction, tremor, and weight gain as commonly reported side effects 1
• While nausea and vomiting are the most common reasons for SSRI discontinuation, sweating can significantly impact quality of life and medication adherence 4

Management Options for SSRI-Induced Sweating

For patients experiencing problematic sweating on fluoxetine:

1. Dose adjustment: Consider reducing the dose if clinically appropriate 4

2. Medication switch: Consider switching to another antidepressant with potentially lower rates of sweating 4

   • For older patients, guidelines suggest citalopram, escitalopram, sertraline, mirtazapine, venlafaxine, and bupropion as preferred agents over fluoxetine 1

3. Adjunctive treatment: Some medications may help control SSRI-induced sweating:

   • Benztropine has been reported to help control sweating 4
   • Cyproheptadine may reduce sweating 4
   • Mirtazapine has been reported to reduce SSRI-induced excessive sweating when used as an adjunctive treatment 5

Special Considerations

• Elderly patients: Fluoxetine should generally be avoided in older adults due to higher rates of adverse effects, including sweating 1
• Discontinuation: If stopping fluoxetine due to sweating, a slow taper is recommended to avoid discontinuation syndrome 1
• Monitoring: Patients should be informed about this potential side effect before starting treatment

Clinical Implications

The presence of excessive sweating may:

• Reduce medication adherence
• Impact quality of life
• Cause social embarrassment
• Lead to skin problems in severe cases

While sweating is not typically dangerous, it can be distressing enough to warrant intervention or medication change in some patients.