Can Remeron (mirtazapine) be used to treat akathisia?

Mirtazapine for Akathisia

Mirtazapine (Remeron) at low doses (7.5-15 mg daily) is an effective treatment option for antipsychotic-induced akathisia and should be considered, particularly when beta-blockers are contraindicated or poorly tolerated.

Evidence for Efficacy

Mirtazapine has demonstrated significant anti-akathisia properties through its potent serotonin 5-HT2A receptor antagonism 1. The evidence supporting its use includes:

• Controlled trial data: Mirtazapine achieved a 53.8% response rate (defined as ≥2-point reduction on Barnes Akathisia Scale global subscale) compared to 7.7% for placebo (p = 0.004) 2
• Comparative effectiveness: In head-to-head comparison, mirtazapine showed 43.3% response rate versus propranolol's 30.0% and placebo's 6.7% (p = 0.0051), with better tolerability than propranolol 2
• Very low-dose efficacy: Even at 7.5 mg daily, mirtazapine produced statistically significant improvements in subjective, distress, and global akathisia subscales (P < 0.01 to P < 0.001), with 41.6% of patients meeting response criteria 3

Recommended Dosing Strategy

Start with 7.5 mg once daily at bedtime 3, 1. This ultra-low dose:

• Maintains anti-akathisia efficacy through 5-HT2A antagonism
• Minimizes sedation and weight gain compared to higher doses
• Shows particular effectiveness in aripiprazole-induced akathisia 3

If inadequate response after 7-10 days, increase to 15 mg daily 1, 2. Do not exceed 15 mg for akathisia treatment, as higher doses used for depression (30-45 mg) are unnecessary and increase side effects 4.

Clinical Algorithm for Akathisia Management

First-line approach:

1. Reduce antipsychotic dose if clinically feasible 4
2. Switch to lower-potency or second-generation antipsychotic with less akathisia risk 5

When medication changes are not feasible:

Primary rescue agents (B-CALM mnemonic) 5:

• Beta-blockers (propranolol 10-30 mg 2-3 times daily): Traditional first-line but limited by contraindications (asthma, bradycardia, orthostatic hypotension) 4, 1
• Clonazepam: Provides symptomatic relief but doesn't address underlying mechanism 4, 5
• Anticholinergics: Not consistently helpful for akathisia specifically 4
• cLonidine: Alternative option 5
• Mirtazapine: Increasingly recognized as effective first-line option 1, 5

When to Choose Mirtazapine

Mirtazapine is particularly advantageous when:

• Beta-blockers are contraindicated (asthma, COPD, heart block, severe bradycardia) 1
• Patient has comorbid depression or negative symptoms requiring treatment 2
• Previous beta-blocker trials failed or caused intolerable side effects 1
• Patient requires simpler once-daily dosing versus propranolol's multiple daily doses 1

Important Caveats

Monitor for drowsiness, the most common adverse effect, though generally well-tolerated at low doses 3, 2. The American Academy of Sleep Medicine notes mirtazapine's sedating properties and association with weight gain at antidepressant doses 4.

Paradoxical akathisia: Rare case reports exist of mirtazapine inducing akathisia, even after years of treatment 6. If akathisia worsens after starting mirtazapine, discontinue immediately and consider alternative agents 6.

Not FDA-approved for akathisia: This represents off-label use, though the evidence base is stronger than for many other akathisia treatments 1, 2.

Monitoring and Follow-up

• Assess response using Barnes Akathisia Rating Scale at baseline and after 7-10 days 3, 2
• Look for reduction in subjective restlessness, distress, and objective motor signs 3
• If no response after 2 weeks at 15 mg, consider switching to propranolol or combining treatments 1, 5
• Re-evaluate need for continued treatment if antipsychotic is reduced or discontinued 4