Benzodiazepine Conversion & Equivalence Calculator

Convert between benzodiazepine doses using diazepam equivalents. Includes a 12-drug equivalence table, half-life context, and general taper-reference notes.

About the Benzodiazepine Conversion & Equivalence Calculator

The Benzodiazepine Conversion Calculator converts between benzodiazepine doses using a diazepam-equivalent reference. Covering 12 commonly prescribed benzodiazepines, it provides equivalent dosing, half-life comparison, onset speed, duration of action, and taper-reference context based on the Ashton Manual and similar withdrawal resources.

Benzodiazepine cross-tapering and dose conversion is commonly used when patients need to switch between agents, such as moving from short-acting alprazolam (Xanax) to long-acting diazepam (Valium) for a controlled taper. Matching the approximate equivalent dose helps reduce the risk of under-dosing and over-dosing during the switch.

This calculator uses standard equipotent dose ratios referenced in the Ashton Manual, the British National Formulary, and major pharmacology textbooks. It also generates an illustrative taper outline using conservative 5-10% weekly reductions, which is a common starting point for slow taper discussions.

Why Use This Benzodiazepine Conversion & Equivalence Calculator?

Dose conversion is useful when a medication switch or taper needs to be reviewed around approximate diazepam equivalents. The calculator keeps the reference table and taper context together so the conversion is easier to review before a clinician finalizes the actual plan.

How to Use This Calculator

  1. Select your current benzodiazepine from the dropdown.
  2. Enter your dose per administration and number of times per day.
  3. Select the benzodiazepine to convert to.
  4. Review the equivalent dose, diazepam reference, and suggested dosing schedule.
  5. Use the equivalence table for a comprehensive comparison of all 12 drugs.
  6. Use the taper section as a reference framework, not as a stand-alone discontinuation plan.

Formula

Diazepam Equivalent (mg) = (Total Daily Dose / Source Drug Equiv) × 5 Target Drug Dose (mg) = (Diazepam Equivalent / 5) × Target Drug Equiv Equivalent doses (mg ≈ 5 mg Diazepam): Alprazolam 0.5, Chlordiazepoxide 25, Clonazepam 0.5, Diazepam 5, Lorazepam 1, Oxazepam 15, Temazepam 15, Triazolam 0.25

Example Calculation

Result: Total: 1.5 mg/day alprazolam = 15 mg/day diazepam = 7.5 mg BID.

Alprazolam 0.5 mg = 5 mg diazepam. Total daily dose 1.5 mg = 3 doses × (5/0.5) = 15 mg diazepam. Diazepam is split into 2 doses due to its long half-life, giving 7.5 mg twice daily.

Tips & Best Practices

The Pharmacology of Benzodiazepine Equivalence

Benzodiazepines all act on GABA-A receptors, but they differ in potency (receptor binding affinity), onset (lipophilicity and absorption), half-life (hepatic metabolism and active metabolites), and selectivity (anxiolytic vs. anticonvulsant vs. hypnotic effects). These differences explain why equivalent doses vary so much — 0.5 mg of alprazolam has the same clinical effect as 25 mg of chlordiazepoxide, a 50-fold dose difference.

Long-Term Benzodiazepine Use and Dependence

Physical dependence can develop within 2-4 weeks of daily use and is nearly universal after months of use. The brain downregulates GABA-A receptors in response to chronic benzodiazepine exposure, resulting in tolerance (needing more for the same effect) and withdrawal when the drug is reduced. Approximately 40% of long-term users will experience significant withdrawal symptoms during tapering.

Protracted Withdrawal Syndrome

Some patients experience protracted withdrawal symptoms lasting months to years after complete cessation. These include anxiety, insomnia, tinnitus, depersonalization, paresthesias, and cognitive difficulties. While controversial, protracted withdrawal is increasingly recognized and may reflect slow receptor recovery. It is more common after long-term use of high-potency short-acting agents (alprazolam, lorazepam).

How to Use the Taper Section Safely

The taper table on this page is meant to show what a conservative taper framework can look like once a clinician has already confirmed the conversion is appropriate. It should not be treated as a direct dose-change schedule. Real tapers often pause, slow down, or switch strategy based on symptoms, comorbid illness, and patient preference.

Sources & Methodology

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Methodology

This worksheet converts a reported benzodiazepine regimen into an approximate diazepam-equivalent reference dose and then uses that intermediate reference to show an approximate equivalent dose for the selected target drug. The taper table is deliberately illustrative and stays in the realm of slow-dose-reduction planning rather than a direct medication schedule.

Equivalence tables for benzodiazepines are approximate and can vary between references. Clinical decisions still depend on the actual indication, tolerance, comorbidity, seizure history, concurrent sedatives, hepatic function, and clinician-supervised taper design.

Sources

Frequently Asked Questions

Why convert to diazepam for tapering?

Diazepam has a long half-life (20-100 hours) with active metabolites lasting even longer. This provides stable blood levels without interdose withdrawal, making it the preferred agent for controlled tapering. Short-acting agents like alprazolam cause fluctuating blood levels that make tapering difficult.

How fast should benzodiazepine tapering be?

Many slow taper plans reduce by about 5-10% of the current dose every 1-2 weeks, then slow further at lower doses. But there is no single correct pace. Duration of use, dose, comorbidity, prior withdrawal history, and patient response can all justify a slower or more individualized schedule.

What are the dangers of abrupt benzodiazepine discontinuation?

Abrupt cessation or rapid dose reduction can cause life-threatening complications: grand mal seizures, delirium tremens-like syndrome, psychosis, and status epilepticus. Even gradual tapering can cause insomnia, anxiety, tremor, dysphoria, and perceptual disturbances. Medical supervision is essential.

Are benzodiazepine equivalence tables exact?

No — equivalence ratios are approximate and based on clinical observation, not precise pharmacological equivalence. Individual variation in metabolism, receptor sensitivity, and tolerance means equivalent doses may differ by 20-50% between patients. These tables are starting points, and doses must be adjusted clinically.

What is the Ashton Manual?

The Ashton Manual, written by Professor C. Heather Ashton (Newcastle University), is one of the most widely cited benzodiazepine-withdrawal references. It provides diazepam-switching examples and taper frameworks, but any real taper still has to be individualized by the treating clinician.

Can Z-drugs (zolpidem, zopiclone) be converted using this table?

Z-drugs act on the same GABA-A receptors but with different subunit selectivity. Approximate equivalents exist (zolpidem 10 mg ≈ diazepam 10 mg) but they are less reliable than benzodiazepine-to-benzodiazepine conversions. Z-drug tapering may require direct dose reduction rather than cross-tapering.

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