Strategies for Optimizing Antiepileptic Drug Therapy in Elderly People

Thomas E. Lackner, Pharm.D., FASCP

Disclosures

Pharmacotherapy. 2002;22(3) 

In This Article

Essential Tremor

Essential tremor is nearly ubiquitous in the elderly.[152] Mild essential tremor generally requires no treatment, and its natural progression is unaltered by therapy.[153] However, resulting disabilities (difficulty or inability to perform activities such as feeding, dressing, or writing) or impaired quality of life often necessitate pharmacotherapy.[153] Primidone is a first-line agent in patients in whom b-adrenergic blockers are contraindicated or not tolerated.[153] Despite no FDA-approved indication for essential tremor, clinical studies including elderly patients reported that primidone is similarly effective as b-adrenergic blockers.[154] One randomized, open-label study evaluated the long- and short-term effects of primidone in 25 patients (mean age 66.6 yrs) and long-acting propranolol in 25 patients (mean age 68.9 yrs) over 12 months.[154] Sixty-eight percent of patients taking primidone experienced decreased tremor, compared with 70% taking propranolol. After 1 year, a diminished tremor was sustained in 13 (52%) and 10 (40%), respectively. The efficacy of primidone was unrelated to its SDC. Acute adverse drug reactions were experienced by 32% of patients taking primidone (3 discontinued treatment) and 8% taking propranolol (6 discontinued treatment). The usual starting dosage of primidone is 25 mg at bedtime, with gradual escalation as necessary up to 250 mg/day as tolerated.

Gabapentin may be effective in managing essential tremor. In a controlled 2-week trial of 16 patients (mean age 67.9 yrs), no significant difference was found in the extent of tremor reduction between gabapentin 400 mg 3 times/day and propranolol 40 mg 3 times/day, and both drugs were significantly better than placebo.[155] Both were well tolerated. In contrast, a double-blind, placebo-controlled, crossover study of 20 patients (mean age 66.5 yrs) reported no significant improvement in total tremor, hand tremor, handwriting, and pouring with gabapentin 1800 mg/day as adjunctive therapy versus placebo in 18 evaluable patients (p>0.05).[156] However, because antitremor therapy was continued during the study, including many individuals who previously responded to propranolol, selection bias (previous responders would continue to respond to preexisting drug) may explain lack of significant gabapentin effect. In a retrospective case series including familial tremor, gabapentin achieved excellent improvement in tremor in one of five elderly patients and moderate improve-ment in the remaining four.[157] Additional studies should establish the role of gabapentin compared with propranolol and primidone. Until then, gabapentin should be considered in patients intolerant to b-blockers and primidone.

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