Drug-Induced Tremor

Tremor — involuntary, rhythmic shaking of one or more body parts,[1] such as the hands, limbs, head, neck or vocal cords — is the single most common movement disorder, affecting millions of people in the U.S.

Generally, tremors occur more frequently in the elderly and in patients with a family history of this movement disorder.

Tremor is not life-threatening. However, in severe cases, it can be disabling at home and in the workplace, as it can impair the functional abilities of affected individuals. In addition, tremor can have considerable negative psychological effects, including social embarrassment and even depression.

Numerous drugs can provoke or worsen tremor.[2] In addition to causing physical and psychological impairment, drug-induced tremor can lead some patients to stop taking their medications without medical supervision, which may result in disease relapse and the need for hospitalization.

Learn about the types of tremor, the main drugs that can be associated with it and options for dealing with drug-induced tremor.

Types of tremor

Tremor is classified into two main types. The first type, resting tremor, occurs when the muscles are relaxed, such as when the hands are resting on the lap, and decreases with movement.[3] Often, this type of tremor only affects the hands or fingers.

The second type, action tremor, is the more common type. It occurs during voluntary muscle movement. There are several sub-types of action tremors, each of which occurs with a different type of voluntary movement. For example, one subtype called intention tremor occurs when moving part of the body toward a target, such as moving a finger to touch the nose. In such cases, the tremor in the finger becomes worse as the finger approaches the nose.

About drug-induced tremor

Drugs can induce both resting tremor and action tremor.[4] Some drugs may cause tremor by interfering with various substances that affect the nervous system, including adrenaline, norepinephrine, dopamine and serotonin. Others may lead to tremors by damaging the brain or nerves. Additionally, certain drugs can trigger or aggravate Parkinson’s disease, in which tremor is a major symptom. However, the exact ways in which drugs cause this adverse event often are unknown.

Notably, the severity of drug induced tremor typically increases as the dose of the causative drug is escalated.[5] Moreover, the onset of tremor can sometimes be due to overdose or abrupt withdrawal of a certain drug.[6]

Health care professionals usually diagnose drug-induced tremor based on detailed physical and neurological examinations and a review of medical and drug-intake history. Importantly, health care professionals should exclude other possible causes of tremor — such as Parkinson’s disease, adrenal gland tumors, alcohol withdrawal, cigarette smoking, multiple sclerosis and overactive thyroid — before establishing a diagnosis of drug-induced tremor.

Drug examples

The drugs with the strongest potential to cause tremor include antiarrhythmics (drugs for abnormal heart rhythms), antidepressants, bronchodilators (drugs for asthma or chronic obstructive pulmonary disease), certain hormones, immunosuppressants and mood stabilizers (see table, below for examples).[7] Additionally, tremor can occur with certain antibiotics, antifungals, antiepileptics (seizure drugs) and gastrointestinal drugs.

Notably, antipsychotics — such as haloperidol (HALDOL) — also can cause tremor. However, the tremor associated with these drugs is often part of tardive dyskinesia, which is a slow-occurring but more serious movement disorder characterized by involuntary jerky movements of different muscles resulting in random movements of the face, lips, tongue, trunk and limbs.

Examples of Drugs That Can Cause Tremor†[8],[9],[10],[11]

† Note: Most combination drugs are not included in this table.
*Classified as Limited Use by Public Citizen’s Health Research Group
**Classified as Do Not Use by Public Citizen’s Health Research Group
***Classified as Do Not Use Except for Serious Fungal Infection by Public Citizen’s Health Research Group

Treatment

If a certain medication is implicated as the cause of tremor, its harm benefit balance should be assessed. If the tremor is mild and does not interfere significantly with occupational or social functioning, changes to this medication may not be necessary.

However, if the harm from the tremor outweighs the drug’s benefits, the drug should be discontinued. This often results in a reversal of the tremor.[12] The patient may be switched to an alternative drug that does not induce tremor.

If the benefit of the drug is greater than the problems caused by the tremor, lower doses of the drug may be attempted to minimize the tremor.

What You Can Do

If you suddenly develop tremor or any abnormal body movements that you cannot control, consult your health care professional to find out whether these movements are related to a medication that you are taking currently or have taken previously.

If a medication is known to cause tremor, you should always be vigilant about this risk and notify your health care professional immediately if it occurs.

Do not stop taking any medication without talking to your health care professional first. If you develop drug-induced tremor, avoid alcohol, caffeinated drinks (including coffee, tea and soda) and tobacco because they can worsen tremors.

References

[1] Elias WJ, Shah BB. Tremor. JAMA. 2014;311(9):948-954.

[2] Drug-induced tremor. Prescrire Int. 2018;27(190):41-44.

[3] National Institute of Neurological Disorders and Stroke. Tremor fact sheet. April 23, 2018. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Tremor-Fact-Sheet. Accessed May 11, 2018.

[4] Drug-induced tremor. Prescrire Int. 2018;27(190):41-44.

[5] Zádori D, Veres G, Szalárdy L, et al. Drug-induced movement disorders. Expert Opin Drug Saf. 2015;14(6):877-890.

[6] Drug-induced tremor. Prescrire Int. 2018;27(190):41-44.

[7] Zádori D, Veres G, Szalárdy L, et al. Drug-induced movement disorders. Expert Opin Drug Saf. 2015;14(6):877-890.

[8] Rosa MM, Anes A. Drug-induced movement disorders. In: Falup-Pecurariu C, Ferreira J, Martinez-Martin P, Chaudhuri KR, eds. Movement Disorders Curricula. Springer, Vienna; 2017:401-406.

[9] Drug-induced tremor. Prescrire Int. 2018;27(190):41-44.

[10] Elias WJ, Shah BB. Tremor. JAMA. 2014;311(9):948-954.

[11] Morgan JC, Sethi KD. Drug-induced tremors. Lancet Neurol. 2005;4(12):866-876.

[12] Drug-induced tremor. Prescrire Int. 2018;27(190):41-44.