What is the equivalent dosage of Xanax (alprazolam) for a patient currently taking clonazepam?

Clonazepam to Xanax (Alprazolam) Dose Equivalency

The equivalent dose of clonazepam for 1 mg of alprazolam (Xanax) is 0.5 mg, as alprazolam is approximately twice as potent as clonazepam. 1

Conversion Algorithm

When converting from clonazepam to alprazolam, use the following ratio:

• 1 mg alprazolam = 0.5 mg clonazepam 1
• Conversely: 1 mg clonazepam = 2 mg alprazolam

This conversion is based on the relative potency differences between these high-potency benzodiazepines, where alprazolam is approximately 10 times more potent than diazepam, while clonazepam is approximately twice as potent as alprazolam. 1

Pharmacokinetic Considerations

Critical differences in half-life must guide your conversion strategy:

• Clonazepam has a significantly longer half-life (30-40 hours) compared to alprazolam (12-15 hours), providing more stable blood levels and less frequent dosing requirements. 1, 2
• Alprazolam reaches peak serum levels in 0.7 to 2.1 hours, while clonazepam reaches maximum plasma concentrations within 1-4 hours. 1, 2
• The longer half-life of clonazepam means patients switching from alprazolam may experience relief from interdose anxiety symptoms that commonly occur with alprazolam. 3

Practical Switching Protocol

When switching from alprazolam to clonazepam (the more common clinical scenario):

• Use a 2:1 ratio (2 mg alprazolam = 1 mg clonazepam). 3
• In a study of 48 patients switched from alprazolam to clonazepam at comparable doses, 82% rated clonazepam "better" due to decreased frequency of administration and elimination of interdose anxiety. 3
• Both medications demonstrated equivalent efficacy for panic disorder at these comparable doses. 3

When switching from clonazepam to alprazolam (less common):

• Use a 1:2 ratio (1 mg clonazepam = 2 mg alprazolam). 1
• Consider the differences in onset of action and half-life to minimize withdrawal symptoms. 1
• Be aware that alprazolam discontinuation is particularly difficult and sometimes associated with serious rebound and withdrawal symptoms. 4

Dosing Ranges

Clonazepam:

• Typical dose range: 0.25 mg to 2.0 mg, though doses as high as 4.0 mg have been reported. 1
• Start with the lowest effective dose, particularly 0.25 mg PRN in elderly, frail, or respiratory-compromised patients. 5

Alprazolam:

• Recommended daily dosage: 0.5 to 4.0 mg. 2
• Average therapeutic dose without excessive sedation: approximately 2 mg daily. 6

Special Population Adjustments

Elderly patients require significant dose reductions:

• Reduce doses by 50% or greater when using either medication in elderly patients. 1
• When combining with antipsychotics, use lower benzodiazepine doses of 0.25-0.5 mg in older or frail patients. 5

Common Pitfalls to Avoid

Underestimating potency differences can lead to over-sedation or under-treatment:

• Failing to account for the 2:1 potency ratio may result in inadequate symptom control when switching to clonazepam or excessive sedation when switching to alprazolam. 1
• Not considering the half-life difference may lead to breakthrough anxiety with alprazolam or excessive accumulation with clonazepam. 1

Alprazolam-specific risks:

• Alprazolam has a particularly difficult discontinuation profile with serious rebound and withdrawal symptoms, making it harder to taper than clonazepam. 4
• Interdose anxiety symptoms occur more commonly with alprazolam due to its shorter half-life. 3

Monitoring Requirements

Essential parameters to monitor during conversion:

• Sedation levels, particularly in the first 1-4 hours after administration. 5
• Respiratory rate and oxygen saturation, especially in patients with COPD or sleep apnea. 5, 1
• Mental status for paradoxical agitation, confusion, or excessive sedation. 5
• Fall risk assessment, as benzodiazepines increase fall risk. 5
• Blood pressure for orthostatic hypotension. 5

Clinical Efficacy Comparison

Both medications demonstrate comparable efficacy for anxiety and panic disorders at equivalent doses. 4, 3 In controlled trials comparing clonazepam and alprazolam for panic disorder, the two active agents had similar positive effects. 4 However, clonazepam's longer half-life permits less frequent dosing and more continuous control of anxiety, though approximately 20% of patients experience unacceptable sedative effects. 4