About This Calculator

The Diazepam Equivalency Calculator is a clinical support tool designed to estimate dose conversions between various benzodiazepines (and Z-drugs) and their approximate equivalent dose of diazepam. This process is a common step in developing a medication tapering schedule, as diazepam's long half-life can provide a smoother withdrawal process compared to shorter-acting agents.

Outputs Explained

Upon entering a drug and its daily dose, the calculator provides the following outputs:

• Equivalent Dose: The calculated daily dose of the target drug (usually diazepam) in milligrams (mg) that is estimated to have a similar clinical effect.
• Calculation Formula: A transparent view of the multiplication or division performed, showing the source dose and the conversion multiplier used.
• Drug Characteristics: A comparative summary of both the source and target drugs, including their half-life, onset of action, potency, and key clinical notes. This context is critical for understanding the pharmacological differences beyond just the dose.

How to Use the Tool

Follow these simple steps to perform a conversion:

1. Select the "Convert From" Drug: Choose the benzodiazepine or Z-drug the patient is currently taking from the dropdown menu.
2. Enter the Daily Dose: Input the total milligrams (mg) the patient takes per day.
3. View the Result: The tool automatically calculates the equivalent dose of the "Convert To" drug, which defaults to Diazepam for most conversions. If starting with Diazepam, you can select a different target drug.

Dosing Overview

Benzodiazepine equivalency is based on established clinical data but should always be considered an approximation. Individual patient factors, such as metabolism, age, liver function, and duration of use, can influence the required dose. The conversion ratios used in this tool are derived from sources like the Ashton Manual and other clinical literature.

The key difference between these medications is often their half-life—the time it takes for the drug's concentration in the body to be reduced by half. Short-acting drugs like alprazolam are eliminated quickly, increasing the risk of inter-dose withdrawal, while long-acting drugs like diazepam provide more stable blood levels.

Switching Medications

Switching from a short-acting benzodiazepine (e.g., alprazolam, lorazepam) to a long-acting one like diazepam is a common strategy for initiating a medically supervised taper. This is done to minimize withdrawal symptoms. The process should be managed carefully by a healthcare professional, who may implement a crossover titration where the dose of the original drug is slowly decreased while the dose of diazepam is slowly increased to the target equivalent dose.

Missed Dose

If a dose is missed, the patient should consult their prescribing healthcare provider for guidance. General advice is to take the missed dose as soon as remembered, unless it is almost time for the next scheduled dose. Doubling the dose to "catch up" can be dangerous and should be avoided. The impact of a missed dose depends on the drug's half-life; missing a dose of a short-acting agent will be felt more quickly.

Safety Alerts

• Risk of Dependence: Benzodiazepines can be habit-forming. Long-term use can lead to physical and psychological dependence.
• Withdrawal Syndrome: Abruptly stopping or rapidly reducing the dose of a benzodiazepine can cause a severe withdrawal syndrome, which can be life-threatening. A gradual, supervised tapering schedule is essential.
• CNS Depression: Benzodiazepines are central nervous system depressants. Combining them with other depressants like alcohol, opioids, or certain antihistamines can lead to profound sedation, respiratory depression, coma, and death.

Frequently Asked Questions (FAQ)

Why is diazepam used as the standard for BZD equivalency?

Diazepam is often the reference drug due to its long half-life (over 100 hours with its active metabolites), which provides stable plasma concentrations and helps prevent inter-dose withdrawal. This makes it a preferred agent for medication tapering protocols.

Are the "Z-drugs" like zolpidem the same as benzodiazepines?

No, Z-drugs (zolpidem, zaleplon, zopiclone) are structurally different from benzodiazepines. However, they are included in this calculator because they act on the same GABA-A receptor complex and can produce similar effects, including dependence and withdrawal.

Can I use this calculator to taper myself off my medication?

No. You must not use this information to self-manage your medication. Benzodiazepine withdrawal can be complex and dangerous, requiring a personalized tapering plan developed and monitored by a healthcare professional.

Why is the equivalent diazepam dose in milligrams so much higher than for alprazolam?

This reflects the difference in potency. Alprazolam is a high-potency benzodiazepine, meaning a small milligram amount (e.g., 0.5 mg) has a strong effect. Diazepam is a low-potency agent, so a larger milligram dose (e.g., 10 mg) is needed to achieve a similar clinical effect.

What does "inter-dose withdrawal" mean?

This refers to withdrawal symptoms that emerge between scheduled doses of a medication. It is common with short-acting benzodiazepines because the drug levels in the blood can fall significantly before the next dose is due.

Is the dose conversion provided by the calculator exact?

No. The conversion is an estimate. The provided ratios are based on population averages, and individual responses can vary. A clinician will use this estimate as a starting point and adjust the dose based on the patient's response and symptoms.

Why do some drugs have notes about being safer in hepatic impairment?

Drugs like lorazepam, oxazepam, and temazepam are metabolized primarily through glucuronidation, a process that is less affected by liver disease compared to the oxidative metabolism required for drugs like diazepam. This makes them a potentially safer choice in patients with significant liver impairment.

What are active metabolites and why do they matter?

Active metabolites are substances formed when the body breaks down a drug, and these substances have their own pharmacological effects. Diazepam is converted into several long-acting metabolites (like desmethyldiazepam), which is the primary reason for its very long overall duration of action.

References

• The Ashton Manual: Benzodiazepine Equivalence Table.
• U.S. Food and Drug Administration. DIAZEPAM tablet prescribing information. DailyMed.
• U.S. Food and Drug Administration. XANAX (alprazolam) tablet prescribing information. DailyMed.
• Griffin, C. E., et al. (2013). Benzodiazepine Pharmacology and Central Nervous System-Mediated Effects. The Ochsner Journal, 13(2), 214–223. Available from: NCBI.
• National Institute for Health and Care Excellence (NICE). (2022). Medicines associated with dependence or withdrawal symptoms: safe prescribing and withdrawal management for adults [NG215].