Do finasteride, rivaroxaban, flecainide, bupropion, omeprazole, lovastatin, gabapentin, simethicone, ondansetron, imodium (loperamide), oxybutynin, cetirizine, docusate, fluoxetine, or losartan cause leg tremors?

Medications That Can Cause Leg Tremors

Among the medications listed, bupropion, fluoxetine, gabapentin, and ondansetron are the most likely to cause leg tremors, with bupropion carrying the highest risk.

High-Risk Medications for Tremor

Bupropion

• Bupropion is explicitly listed as causing leg cramps and tremor in its FDA prescribing information 1
• Tremor is one of the most common adverse effects requiring drug discontinuation with bupropion, occurring in 7-12% of patients in clinical trials 2
• Case reports document progressive tremor, truncal ataxia, and myoclonic jerks with bupropion, particularly in elderly patients with renal impairment 3
• The American Academy of Sleep Medicine specifically recommends against bupropion for restless legs syndrome due to its potential to worsen movement symptoms 4
• Bupropion causes tremor through enhancement of physiological tremor via its effects on norepinephrine and dopamine neurotransmission 5, 6

Fluoxetine (and SSRIs)

• SSRIs including fluoxetine commonly cause sweating, tremors, nervousness, and various gastrointestinal disturbances 2
• Selective serotonin reuptake inhibitors are recognized tremorogenic drugs that can cause or exacerbate tremors 7
• Fluoxetine is specifically listed among antidepressants that cause tremor through central mechanisms 5

Gabapentin

• While gabapentin is used to treat restless legs syndrome, it paradoxically can cause tremor as a side effect 4
• Common adverse effects of gabapentin include somnolence and dizziness, with tremor reported in clinical use 4
• Gabapentin is associated with altered mental status and falls, particularly in patients with renal impairment 4

Ondansetron

• Ondansetron can cause myocardial ischemia through coronary vasospasm, which may indirectly lead to tremor 2
• It is listed among medications that can cause cardiovascular effects potentially leading to movement symptoms 2

Moderate-Risk Medications

Flecainide

• Flecainide can slow intra-atrial conduction and is listed among medications affecting cardiac electrophysiology 2
• When used with bupropion, flecainide levels may increase as bupropion inhibits CYP2D6, which metabolizes flecainide 1

Losartan

• Losartan and other angiotensin receptor blockers (candesartan, irbesartan, olmesartan, telmisartan, valsartan) are associated with drug-induced photosensitivity but not directly with tremor 2

Low-Risk Medications

The following medications are not typically associated with tremor:

• Finasteride: No evidence linking it to tremor in the provided guidelines or research 2
• Rivaroxaban: Not mentioned as causing tremor in cardiovascular or movement disorder literature 2
• Omeprazole: No association with tremor found 2
• Lovastatin: Statins (atorvastatin, pravastatin, simvastatin) are associated with photosensitivity but not tremor 2
• Simethicone: No tremor association documented 2
• Loperamide (Imodium): No tremor association in the evidence 2
• Oxybutynin: Anticholinergic effects but no specific tremor association 2
• Cetirizine: Antihistamines can exacerbate restless legs syndrome but are not directly linked to tremor 4
• Docusate: No tremor association 2

Clinical Management Approach

If tremor develops after starting any of these medications:

1. Immediately suspect bupropion, fluoxetine, or gabapentin as the most likely culprits based on temporal relationship 1, 3
2. Consider dose reduction first rather than immediate discontinuation, particularly for bupropion where symptoms may improve within 36-48 hours of dose lowering 3
3. Evaluate for risk factors: elderly age, renal impairment, polypharmacy, and high doses increase tremor risk 8, 3
4. Distinguish tremor type: drug-induced tremor usually resembles enhanced physiological tremor (8-12 Hz, postural/action tremor) rather than parkinsonian tremor 5, 8
5. Monitor for resolution: most drug-induced tremors resolve after discontinuation, though some may persist (tardive tremor) 8

Critical Pitfall to Avoid

Do not assume that because gabapentin treats restless legs syndrome, it cannot cause tremor—it has a dual profile where it reduces RLS symptoms but can simultaneously cause tremor as an adverse effect, particularly at higher doses or in patients with renal impairment 4.