What non‑beta‑blocker medication can be used to treat essential tremor in an elderly male patient who is experiencing bradycardia from bisoprolol?

Alternative Treatment for Essential Tremor in an Elderly Patient with Bisoprolol-Induced Bradycardia

Discontinue bisoprolol immediately and initiate primidone as first-line alternative therapy for essential tremor, starting at a low dose of 25–50 mg at bedtime and titrating gradually to minimize adverse effects. 1, 2

Immediate Management of Bradycardia

• Stop bisoprolol now—symptomatic bradycardia with heart rates in the 40s represents an absolute contraindication to continued beta-blocker therapy in elderly patients. 1
• Check blood pressure, assess for signs of hypoperfusion, and obtain a 12-lead ECG to rule out high-grade AV block before initiating alternative tremor therapy. 1
• The European Society of Cardiology explicitly identifies symptomatic bradycardia as a contraindication requiring immediate discontinuation of beta-blockers. 1

First-Line Alternative: Primidone

Primidone is the preferred non-beta-blocker medication for essential tremor and is considered equally effective to propranolol. 2, 3

Dosing Strategy

• Start with 25–50 mg at bedtime to minimize acute side effects (sedation, nausea, dizziness). 2
• Increase by 25–50 mg every 1–2 weeks as tolerated, targeting a maintenance dose of 62.5–250 mg daily (divided into 2–3 doses). 2, 4
• Approximately 50% of patients achieve adequate tremor control with primidone monotherapy. 2, 4

Common Pitfalls

• Acute toxic reaction: Up to 25% of patients experience severe sedation, nausea, or ataxia with the first dose—starting low and titrating slowly prevents this. 2
• If the patient cannot tolerate primidone despite slow titration, consider alprazolam or topiramate as second-line agents. 2, 5

Second-Line Alternatives

Alprazolam

• Effective at low doses (mean 0.75 mg daily) and equipotent to primidone in controlled trials. 5
• Particularly useful in elderly patients who cannot tolerate primidone or propranolol, especially if anxiety coexists with tremor. 5
• Caution: Risk of dependence and falls in the elderly; reserve for patients with concurrent anxiety or those who fail primidone. 5

Topiramate

• Classified as "probably effective" for essential tremor, typically dosed 25–400 mg daily in divided doses. 3, 4
• Side effects include cognitive slowing, paresthesias, and weight loss—may be poorly tolerated in elderly patients. 3

Gabapentin

• Effective as monotherapy (300–1200 mg three times daily) but not as adjunct therapy. 3, 4
• Better tolerated than topiramate in elderly patients but less effective than primidone or propranolol. 3

Agents to Avoid

Other Beta-Blockers

• Do not switch to metoprolol or atenolol—while these beta-1 selective agents carry lower bradycardia risk than bisoprolol, they are significantly less effective for tremor and may still cause bradycardia in elderly patients. 6, 2, 4
• The 2022 Hypertension guidelines warn that lowering heart rate below 70 bpm toward 60 bpm in elderly patients is associated with serious adverse cardiovascular events. 6

Calcium Channel Blockers

• Diltiazem and verapamil are not effective for essential tremor and also carry bradycardia risk—they should not be used as tremor therapy in this patient. 6

Algorithm for Treatment Selection

1. Discontinue bisoprolol immediately due to symptomatic bradycardia. 1
2. Start primidone 25–50 mg at bedtime, titrate slowly over 4–6 weeks to 125–250 mg daily. 2, 4
3. If primidone fails or is not tolerated: Consider alprazolam 0.25–0.75 mg daily (especially if anxiety present) or topiramate 25–100 mg twice daily. 3, 5
4. If pharmacotherapy fails: Refer for deep brain stimulation or focused ultrasound thalamotomy, which provide tremor control in approximately 90% of patients. 2, 7

Monitoring Recommendations

• Reassess tremor severity and functional disability 4–6 weeks after reaching target primidone dose. 2
• Monitor for sedation, ataxia, and cognitive effects, particularly during dose titration. 2
• Ensure heart rate has normalized (>60 bpm) after bisoprolol discontinuation before attributing any residual symptoms to the new tremor medication. 1

Critical Safety Point

Never restart beta-blockers in this patient for tremor control—a Cochrane review reported that 64% of patients taking beta-blockers for tremor experienced substantial falls in heart rate, with one patient withdrawing after heart rate dropped to 56 bpm. 1 The risk of recurrent symptomatic bradycardia, falls, and syncope in an elderly patient outweighs any potential tremor benefit from beta-blocker therapy. 1