Table 2.

Overview of pharmacological agents for essential tremor.

PHARMACOLOGICAL AGENT	LINE OF THERAPY	INITIAL DOSE	TYPICAL DAILY DOSE	TYPICAL THERAPEUTIC RESPONSE RATE AND DROPOUT RATE	MOST COMMON ADVERSE EFFECTS
Propranolol	First line	20 mg BID 10 mg BID in elderly patients	60 to 320 mg/day BID dosing for short-acting or QD dosing for propranolol LA	50%–70% response rate with average 50% improvement of tremor dropout rate 20%	hypotension, bradycardia, fatigue, erectile dysfunction, drowsiness, exertional dyspnea seen in 60% of patients
Primidone	First line	50 mg QHS 25 mg QHS in elderly patients	250 to 750 mg/day QHS dosing, higher doses given as BID	30%–50% response rate average 50–70% of tremor improvement dropout rate 20%–30%	sedation, fatigue, dizziness, ataxia, confusion, nausea, flu-like symptoms seen in 22%–72% of patients
Gabapentin	Second line	300 mg TID 100 mg TID in elderly patients	1200 to 3600 mg/day TID dosing	~30% response rate with 30%–40% tremor improvement dropout rate 10%	sedation, dizziness, ataxia, nausea, weight gain in 30%–40% of patients
Pregabalin	Second line	50 mg BID 25 mg QD in elderly patients	150 to 600 mg/day BID dosing	30%–50% response rate with 30%–40% tremor improvement dropout rate 10%	sedation, dizziness, ataxia, nausea, weight gain frequency and dropout rates similar to gabapentin
Topiramate	Second line	25 mg BID 25 mg QHS in elderly patients	150 to 300 mg/day BID dosing	30%–40% response rate with 20%–37% tremor improvement dropout rate 30%	paresthesias, concentration difficulties, nausea, somnolence, fatigue, malaise, dyspepsia, weight loss, confusion, abnormal taste perception, acute angle closure glaucoma seen in 50% of patients
Clonazepam	Second line	0.5 mg QD 0.25 mg QD in elderly patients	0.5 to 4 mg/day BID dosing	50%–75% response rate with 30%–50% improvement of tremor Dropout rate was <10% in small ET trials	sedation, cognitive impairment, tolerance, dependency, abuse, withdrawal symptoms side effects seen in 50% patients with ET
Alprazolam	Second line	0.25 mg QD 0.125 mg QD in elderly patients	0.125 to 3 mg/day TID dosing	75% response rate with 50% tremor reduction Dropout rate was <10% in small ET trials	sedation, cognitive impairment, tolerance, dependency, abuse, withdrawal symptoms frequency of side effects similar to clonazepam
Atenolol	Second line	50 mg QD	50 to 150 mg/day QD dosing	only patients responding to propranolol improve with 37% tremor reduction dropout rate similar to other β-blockers	similar to propranolol but without possible bronchospasm
Metoprolol	Second line	50 mg BID 25 mg BID in elderly patients	100 to 300 mg/day BID dosing	similar to propranolol but long-term efficacy is not maintained dropout rate similar to other β-blockers	similar to propranolol
Nimodipine	Third line	30 mg QD	120 mg/day QID dosing	50% tremor reduction in more that 50% patients responding but overall number of reported patients is very small and dropout rate is unknown	hypotension, edema, headaches in 10%–20% of patients
Clozapine	Third line	25 mg QD 12.5 mg QD in elderly patients	25 to 75 mg/day QD dosing	50% tremor reduction with 75% response rate in small clinical trials Dropout rate has not been determined for ET patients	sedation, orthostatic hypotension, tachycardia, syncope, weight gain, bone marrow suppression with agranulocyosis Side effects seen in approximately 50% patients but they tend to be transient Overall risk of neutropenia is 3% but it was not observed in ET trials