Can DULOXETINE (duloxetine) or ISDN (isosorbide dinitrate) cause excessive sweating as a side effect?

Medication-Induced Excessive Sweating: Duloxetine as the Primary Cause

Duloxetine is the most likely cause of the patient's excessive sweating, as it is a well-documented side effect of this medication occurring in up to 16% of patients. 1, 2

Medication Review and Causality Assessment

Primary Suspect: Duloxetine

• The patient is taking a high dose (90mg daily) of duloxetine
• Excessive sweating is a frequently reported side effect of duloxetine 2
• Higher doses (like the 90mg this patient is taking) increase the risk of side effects including sweating 1
• Duloxetine's mechanism as a serotonin-norepinephrine reuptake inhibitor (SNRI) directly affects thermoregulation pathways 1

Secondary Suspect: ISDN (Isosorbide Dinitrate)

• ISDN can cause vasodilation which may contribute to sweating
• However, sweating is not listed as a primary side effect in guidelines 1
• The temporal pattern of nitrate-induced vasodilation typically causes flushing rather than persistent sweating

Other Medications (Less Likely Contributors)

• Lorazepam, Dayvigo (lemborexant), esomeprazole, diltiazem, bisoprolol, ASA, and ezetimibe are not commonly associated with excessive sweating

Management Algorithm for Duloxetine-Induced Sweating

1. Confirm causality

   • Rule out other medical causes (thyroid disorders, infections, malignancy)
   • Consider temporal relationship between duloxetine initiation/dose increases and onset of sweating

2. Intervention options (in order of preference):

   a. Dose reduction of duloxetine 3

   • Consider reducing from 90mg to 60mg daily
   • Monitor for both sweating improvement and continued efficacy for depression/pain

   b. Medication switch if dose reduction is ineffective or not feasible:

   • Consider switching to sertraline which has lower risk of causing excessive sweating 4
   • Alternative: mirtazapine has been reported to reduce SSRI/SNRI-induced sweating 5

   c. Pharmacological management if medication cannot be changed:

   • Add benztropine 1-2mg daily (anticholinergic that can reduce sweating) 3
   • Alternative: cyproheptadine 4mg daily (antiserotonergic that can counteract sweating) 3

Important Clinical Considerations

• Sweating severity assessment: Determine impact on quality of life and daily functioning
• Underlying conditions: The patient's medication list suggests possible cardiovascular disease, diabetes, and pain/psychiatric conditions that may influence treatment decisions
• Medication interactions: Be cautious with anticholinergic add-on treatments as they may interact with other medications the patient is taking

Common Pitfalls to Avoid

• Don't abruptly discontinue duloxetine as this can cause withdrawal symptoms
• Don't ignore the sweating as it can significantly impact quality of life and medication adherence
• Don't automatically add another medication before trying dose reduction
• Don't overlook non-pharmacological approaches such as wearing light clothing, avoiding triggers (caffeine, spicy foods), and maintaining cool ambient temperatures

Monitoring Recommendations

• Follow up within 2-4 weeks after any medication change
• Assess both sweating symptoms and the condition being treated by duloxetine
• Monitor for any new side effects if medication is changed or added

If sweating persists despite these interventions, consider referral to a specialist for further evaluation of other potential causes or advanced management strategies.