A tremor is an involuntary, rhythmic shaking of any part of the body that you cannot control. It occurs due to muscle contractions and can affect the hands, head, arms, legs, trunk, or vocal cords. Tremors can be symptoms of certain medical conditions like Parkinson’s disease. Also, certain medications can cause tremors as a side effect.

Please continue reading to learn 5 common medications that can be responsible for inducing tremors or making tremors worse. We will also talk about how to recognize medication-induced tremors and possible treatment options.

What is a medication-induced tremor? How is it different from an essential tremor?

A medication-induced tremor occurs as a side effect of medicines. It is an involuntary shaking that you cannot control. It can start on its own, and you cannot stop it when you try.

In contrast, the exact underlying cause of essential tremor is unknown. Essential tremor is a neurological disorder in which involuntary and rhythmic shaking affects a part of the body, typically in the hands and forearms. It can be an action tremor that occurs when you try to do simple tasks like picking up something or drinking from a glass. While it is not life-threatening, many patients find an essential tremor affects their quality of life.

The main difference between drug-induced tremor and essential tremor is that the exact mechanism and cause of essential tremor are not known. Another difference between these two types of tremor is that drug-induced tremor tend to be quick and usually occur in cycles that last about 10 seconds.

People with Parkinson’s disease can have a resting tremor that occurs at rest or a postural tremor that occurs when adopting a posture against gravity, such as holding the arms out. Other movement disorders may also be associated with tremors.

Drug-induced tremor can be alleviated by discontinuing the offending drug, but do not do so unless consulting your doctor or pharmacist.

What medications can cause drug-induced tremors?

Immunosuppressants

These drugs are used in patients after organ transplants to prevent the rejection of the transplanted organs. Many patients have experienced tremors with immunosuppressants, especially when the serum drug level is high. Examples are tacrolimus and cyclosporine.

Asthma medicines

Medications prescribed to asthma patients, such as albuterol (Ventolin, Proair, Proventil), salmeterol (Serevent), and arformoterol (Brovana) inhalers, can cause medication-induced tremor as a side effect. Up to 20% of people who take these medications develop tremors. The risk of tremors is greater at treatment with higher doses.

Certain antibiotics

Some antibiotics may be associated with drug-induced tremors. Examples include aminoglycosides (gentamicin), glycopeptides (vancomycin), cephalosporins (cefuroxime), macrolides (erythromycin), fluoroquinolones (ciprofloxacin), carbapenems (imipenem), folate synthesis inhibitors (trimethoprim-sulfamethoxazole), penicillins, and tetracyclines (doxycycline).

Thyroid medicine

Taking too much levothyroxine (Levoxyl, Synthroid), a medication used to treat hypothyroidism (underactive thyroid gland), can cause tremors, a symptom of hyperthyroidism.

Antidepressant drugs

Tricyclic antidepressants like amitriptyline can cause tremor progression or an increase in tremor amplitude or tremor severity, i.e., it can make a tremor more noticeable. Selective serotonin reuptake inhibitors (SSRIs) like citalopram (Celexa) and fluoxetine (Prozac) and serotonin and norepinephrine reuptake inhibitors (SNRIs) like venlafaxine (Effexor) can cause twitching and hand tremor. Stopping these medications abruptly can cause tremors due to withdrawal effects.

Certain antihypertensives

Even though antihypertensive agents are not the most concerning drug class when it comes to tremors, some medications used to treat high blood pressure, such as aliskiren and amlodipine, have been linked to drug-induced tremors. Keep in mind that the risk is low. Talk to your doctor if you notice symptoms of tremors while on medication for high blood pressure.

What other medications can cause a medication-induced tremor?

Multiple medications can cause tremors, including cancer medicines (thalidomide, cytarabine), anti-seizure medications (sodium valproate [Depakene] and valproic acid [Depakote]), medications used to treat mood disorders like bipolar disorder (lithium carbonate), heart medications (amiodarone, procainamide), antivirals (vidarabine, acyclovir), epinephrine, norepinephrine, tiratricol (a weight loss medicine), tetrabenazine (a medicine for movement disorders), and substances like amphetamines, caffeine, nicotine, and alcohol.

How to recognize a drug-induced tremor?

Let a doctor determine the differential diagnosis, i.e., whether you have a medication-induced tremor or other hyperkinetic movements. However, here are some clues that could indicate you have a drug-induced tremor:

You don’t have any other medical condition such as hyperthyroidism or Parkinson’s disease that can cause tremors.
Your tremor appears within an hour of taking a medication.
Your tremor became noticeable after your medication dose was increased.
Shakiness in the affected body part is stable and not getting worse.

The tremor caused by medicine can affect various body parts such as the eyelids, head, arms, hands, and voice. The lower body is less commonly affected. One side of the body can be affected more than the other.

The tremor can occur episodically after taking the medication, intermittently in bursts, or occasionally without correlation to medication intake.

A medication-induced tremor can be an action tremor that occurs with movement or a resting tremor that occurs at rest. It usually disappears during sleep. Emotional stress and voluntary movements can make drug-induced tremors worse.

What is the treatment for medication-induced tremor?

A medication-induced tremor usually disappears when you stop taking the medicine that is causing the involuntary movement. Keep in mind that it can take up to a year or more for the symptoms to completely resolve. You should not stop taking any medication without talking to your healthcare provider first. Your doctor will diagnose the cause of your tremor based on your medical history, physical exam, and blood tests.

If your drug-induced tremor is not severe and does not interfere with daily activities, you may not need any treatment. However, if there are possible complications, such as problems with eating, drinking, and other daily activities, stopping the causative medicine or treatment with additional medication may be necessary.

If you cannot discontinue the medicine that is causing your tremor, your healthcare provider may change your medication dose or switch you to another medicine to treat your health condition.

Rarely a medicine like propranolol, used to treat essential tremor, may be prescribed to control a medication-induced tremor. Treatments like deep brain stimulation and surgery are usually reserved for severe tremors that do not respond to other therapies.

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