What is a suitable Clonazepam (Klonopin) dosage for a patient with a long history of taking Alprazolam (Xanax) 0.5 mg twice a day (BID)?

Clonazepam Dosing for Conversion from Alprazolam 0.5 mg BID

For a patient taking alprazolam 0.5 mg BID (1 mg total daily), the equivalent clonazepam dose is 0.5 mg daily, typically given as 0.25 mg BID or 0.5 mg at bedtime. 1

Conversion Rationale

The standard benzodiazepine equivalency ratio between alprazolam and clonazepam is approximately 2:1, meaning 2 mg of alprazolam equals roughly 1 mg of clonazepam. 1 Therefore:

• Alprazolam 1 mg daily = Clonazepam 0.5 mg daily 1

Dosing Schedule Options

Option 1 (Preferred): Clonazepam 0.5 mg once daily at bedtime 2

• Takes advantage of clonazepam's longer half-life (30-40 hours vs alprazolam's 6-12 hours) 1
• Provides continuous anxiety control throughout the day 3
• Reduces clock-watching and eliminates breakthrough anxiety from missed doses 4

Option 2: Clonazepam 0.25 mg BID 2

• May be preferred if patient has concerns about single daily dosing
• Still provides more continuous coverage than alprazolam BID due to longer half-life 1

Critical Pharmacokinetic Differences

Clonazepam's significantly longer half-life (30-40 hours) compared to alprazolam (6-12 hours) fundamentally changes dosing dynamics. 1 This means:

• Slower onset of withdrawal symptoms if a dose is missed 1
• Greater drug accumulation with repeated dosing 1
• Less frequent dosing required for continuous anxiety control 3
• Clonazepam permits less frequent dosing and more continuous control of anxiety compared to shorter-acting benzodiazepines 3

Mandatory Safety Warnings

Before initiating conversion, screen for: 1

• Sleep apnea (clonazepam may worsen it even at doses of 0.5-1.0 mg) 1
• Gait disorders and fall risk 1
• Liver disease 1
• Perform baseline cognitive and motor coordination assessment 1

Common adverse effects to monitor: 1, 3

• Morning sedation and cognitive impairment (reported in up to 58% of patients) 1
• Falls and confusion, especially at doses ≥2 mg 1
• Risk of subdural hematoma from falls 1
• Approximately 20% of patients experience unacceptable sedative effects 3

Conversion Protocol

Perform gradual cross-titration to minimize withdrawal symptoms and rebound anxiety: 1

1. Week 1: Start clonazepam 0.25 mg at bedtime while continuing alprazolam 0.5 mg BID
2. Week 2: Reduce alprazolam to 0.5 mg once daily (morning), continue clonazepam 0.25 mg at bedtime
3. Week 3: Discontinue alprazolam, increase clonazepam to 0.5 mg at bedtime

This gradual approach accounts for the different half-lives and receptor profiles of each medication. 1

Ongoing Monitoring Requirements

Monitor regularly for: 1

• Excessive sedation
• Cognitive function decline
• Fall risk assessment at each visit
• Signs of respiratory depression if sleep apnea is present 1

Reassess need for continued treatment periodically, as the physician who elects to use clonazepam for extended periods should reevaluate the long-term usefulness of the drug for the individual patient. 2

Discontinuation Considerations

Discontinuation of clonazepam is challenging: 1

• Patients typically unable to substantially reduce doses despite tapering attempts 1
• Same-night relapse can occur if clonazepam is missed 1
• When discontinuation is desired, decrease by 0.25 mg per week 5
• Gradual tapering over 4 months is recommended for intermediate-term use 5

Common Pitfall to Avoid

Do not use a 1:1 conversion ratio. Alprazolam is approximately 10 times more potent than diazepam, while clonazepam has similar high potency. 6 The 2:1 ratio (alprazolam:clonazepam) is well-established and prevents overdosing. 1