What medications can cause tremors?

Medications That Cause Tremors

The most common medications causing tremor include SSRIs/SNRIs, lithium, valproate, beta-adrenergic agonists, dopamine receptor antagonists, amiodarone, and tricyclic antidepressants, with tremor typically manifesting as enhancement of physiological tremor or parkinsonian-type tremor depending on the drug class. 1, 2

Antidepressants and Psychotropic Medications

SSRIs and SNRIs

• SSRIs commonly cause tremor as a dose-related adverse effect, with sweating, nervousness, and tremors reported as typical side effects across this drug class 3
• Fluoxetine, paroxetine, sertraline, citalopram, escitalopram, and fluvoxamine all carry tremor risk, though the mechanism likely involves both peripheral and central nervous system effects 3, 4, 2
• SNRIs (duloxetine, venlafaxine, desvenlafaxine, levomilnacipran) cause tremor through similar serotonergic mechanisms and may have slightly higher discontinuation rates due to adverse effects compared to SSRIs 3
• In the context of serotonin syndrome, tremor appears alongside neuromuscular hyperactivity (clonus, hyperreflexia, muscle rigidity) and autonomic symptoms, typically within 24-48 hours of combining serotonergic medications 3

Tricyclic Antidepressants

• TCAs including amitriptyline, desipramine, nortriptyline, doxepin, and imipramine cause tremor, likely through central mechanisms affecting physiological tremor 3, 5
• Desipramine may cause tachycardia in addition to tremor, while nortriptyline tends to be more sedating 3

Other Antidepressants

• Bupropion can cause tremor and should be avoided in patients with seizure disorders 3
• Mirtazapine is generally well-tolerated but tremor remains a potential adverse effect 3

Mood Stabilizers and Anticonvulsants

Lithium

• Lithium is one of the most well-recognized causes of drug-induced tremor, typically producing a fine postural tremor that can progress to more severe tremor at higher doses 1, 2
• Elderly patients are particularly prone to neurotoxicity at higher lithium dosages, with therapeutic levels of 0.2-0.6 mEq/L generally adequate in older adults 3

Valproate

• Valproate commonly causes tremor as a dose-related adverse effect 1, 2

Cardiovascular Medications

Beta-Adrenergic Agonists

• Beta-agonists (albuterol, salmeterol, terbutaline) cause tremor through peripheral β-adrenergic receptor stimulation in muscle, representing classic enhancement of physiological tremor 3, 1, 5
• Epinephrine causes tremor primarily through peripheral mechanisms 5

Amiodarone

• Amiodarone causes tremor both as a direct effect and potentially through secondary effects such as inducing hyperthyroidism 1, 5

Antipsychotics and Dopamine-Blocking Agents

Dopamine Receptor Antagonists

• Typical and atypical antipsychotics cause parkinsonian tremor through dopamine receptor blockade in the basal ganglia 1, 5
• Phenothiazines and most atypical antipsychotics metabolized by CYP2D6 carry tremor risk, with potential for drug interactions when combined with fluoxetine 4
• Haloperidol and clozapine blood levels can be elevated by concomitant fluoxetine, potentially increasing tremor risk 4

VMAT2 Inhibitors

• VMAT2 inhibitors are associated with drug-induced tremor 1

Sympathomimetic and Stimulant Drugs

• Pseudoephedrine, phenylephrine, amphetamines, midodrine, and clonidine cause tremor through sympathomimetic effects 3
• Cocaine and methamphetamine produce tremors and neurobehavioral abnormalities 6
• Caffeine is a well-recognized cause of tremor, producing jitteriness that can last 1-7 days in neonates exposed in utero 6, 2

Opioids and Pain Medications

• Tramadol, meperidine, methadone, and fentanyl can cause tremor, with particular concern when combined with serotonergic medications due to risk of serotonin syndrome 3

Other Medications

MAO Inhibitors

• Phenelzine, isocarboxazid, selegiline, linezolid, and tranylcypromine carry risk of tremor and serious interactions with serotonergic drugs 3
• Isoniazid is included among MAOIs that play a role in serotonin syndrome cases 3

Immunomodulatory Drugs

• Ozanimod (S1P receptor modulator) may interact with medications causing tremor, though direct tremor causation is not clearly established 3

Clinical Risk Factors and Management Considerations

Risk factors for developing drug-induced tremor include polypharmacy, male gender, older age, high doses, and immediate-release preparations or reaching toxic drug levels 1

Key Management Principles:

• Drug-induced tremor usually resolves once the offending medication is discontinued, though persistent "tardive tremor" may occur in some cases 1
• When SSRI-induced tremor occurs early in treatment or with dose increases, consider dose reduction or slower up-titration, particularly in younger children 3
• Behavioral activation with tremor typically improves quickly after SSRI dose decrease or discontinuation 3
• Avoid combining multiple serotonergic drugs without careful monitoring, starting the second agent at low dose and increasing slowly, with particular vigilance in the first 24-48 hours after dosage changes 3

Common Pitfalls:

• Failing to recognize that approximately 63% of patients on second-generation antidepressants experience at least one adverse effect, with tremor being commonly reported 3
• Not considering drug-drug interactions that can elevate levels of tremor-causing medications (e.g., fluoxetine inhibiting CYP2D6 metabolism of other drugs) 4
• Missing the distinction between benign drug-induced tremor and serotonin syndrome, which requires immediate hospitalization and discontinuation of all serotonergic agents 3