What Are Benzodiazepines?
Benzodiazepines are a group of drugs used for treating anxiety — they will also make you feel more relaxed, help you fall asleep faster and, on top of that, may combat a few kinds of seizures. 🧘
Benzodiazepines are a newer generation of drugs that almost totally replaced the older type of anti-anxiety drugs, barbiturates. Why are benzodiazepines so popular? In comparison to barbiturates, they are:
- Much safer;
- Less toxic;
- Overdose is less probable; and, most importantly;
- There's a specific antidote called flumazenil, which can reverse the effects of benzodiazepines within seconds.
Benzodiazepine Half-Life & Classification
The list of benzodiazepines can be divided into 3 groups based on the duration of their action:
- Short-acting (half-life under 12 hours): Alprazolam (Xanax), Midazolam (Versed), Triazolam (Halcion), Oxazepam (Serax). These act quickly and leave the body faster, but withdrawal symptoms can be more intense.
- Medium-acting (half-life 12–24 hours): Lorazepam (Ativan), Bromazepam, Estazolam, Temazepam. A balanced option for many clinical uses.
- Long-acting (half-life over 24 hours): Diazepam (Valium), Clonazepam (Klonopin), Chlordiazepoxide (Librium), Flurazepam. These stay in the body longer, providing more stable coverage but may accumulate with repeated doses.
Benzodiazepine Equivalency Table — Benzo Conversion Chart
All equivalencies below are expressed relative to 5 mg of diazepam (Valium), the standard reference drug. A smaller equivalent dose means the drug is more potent per milligram.
| Drug (Brand Name) | Equivalent to 5 mg Diazepam | Half-Life | Class |
|---|---|---|---|
| Alprazolam (Xanax) | 0.25 mg | 6–12 h | Short |
| Bromazepam | 3 mg | 10–20 h | Medium |
| Chlordiazepoxide (Librium) | 10 mg | 30–100 h | Long |
| Clobazam | 10 mg | 12–60 h | Long |
| Clonazepam (Klonopin) | 0.25 mg | 18–50 h | Long |
| Clorazepate | 7.5 mg | 36–200 h | Long |
| Diazepam (Valium) | 5 mg | 20–100 h | Long |
| Estazolam | 0.5 mg | 10–24 h | Medium |
| Flunitrazepam (Rohypnol) | 0.5 mg | 16–35 h | Long |
| Flurazepam | 7.5 mg | 40–100 h | Long |
| Halazepam | 20 mg | 14–100 h | Long |
| Ketazolam | 15 mg | 30–100 h | Long |
| Lorazepam (Ativan) | 0.5 mg | 10–20 h | Medium |
| Medazepam | 10 mg | 36–200 h | Long |
| Midazolam (Versed) | 2.5 mg | 1–4 h | Short |
| Nitrazepam | 5 mg | 15–38 h | Long |
| Nordazepam | 10 mg | 36–200 h | Long |
| Oxazepam (Serax) | 15 mg | 4–15 h | Short |
| Prazepam | 10 mg | 36–200 h | Long |
| Quazepam | 7.5 mg | 25–100 h | Long |
| Temazepam | 10 mg | 8–22 h | Medium |
| Triazolam (Halcion) | 0.125 mg | 2–5 h | Short |
How the Benzodiazepine Conversion Calculator Works
The calculator uses the diazepam equivalency table to convert a dose from one benzodiazepine to another in two steps:
- Convert the source dose to its diazepam equivalent:
Diazepam equivalent = Source dose × (5 mg ÷ Source drug equiv.) - Convert the diazepam equivalent to the target drug:
Target dose = Diazepam equivalent × (Target drug equiv. ÷ 5 mg)
This simplifies to: Target dose = Source dose × (Target equiv. ÷ Source equiv.)
Example: Converting 1 mg Alprazolam (Xanax) to Diazepam (Valium):
Target dose = 1 mg × (5 mg ÷ 0.25 mg) = 20 mg Diazepam
What Are Other Anxiolytic Medications?
Benzodiazepines are not the only drugs used for anxiety. Treatment often starts with medicines that have a milder effect and are less addictive, such as Benadryl (diphenhydramine). Different opioids such as morphine or tramadol can also be used for anxiety, although the patient may face various side effects.
Some chronic pain drugs such as gabapentin can be used off-label to treat anxiety. Beta-blockers and melatonin may also be administered to alleviate additional effects of anxiety, such as rapid heartbeat or insomnia.
FAQs
- Is benzodiazepine conversion exact?
- No. Equivalency tables are approximate guides based on clinical literature. Individual response to drugs varies due to metabolism, tolerance, body weight, age, and medical history. Always consult a healthcare professional before making any changes.
- Why is diazepam used as the reference?
- Diazepam (Valium) is one of the oldest and most studied benzodiazepines, making it the universal reference point in equivalency tables. Its 5 mg dose is the widely accepted standard unit.
- What is clonazepam (Klonopin) vs. alprazolam (Xanax) equivalent?
- Both are equivalent to 0.25 mg per 5 mg diazepam, meaning 0.5 mg alprazolam ≈ 0.5 mg clonazepam. However, clonazepam is long-acting (18–50 h) while alprazolam is short-acting (6–12 h), so clinical effects differ significantly.
- Can I switch benzodiazepines on my own?
- No. Switching between benzodiazepines must be supervised by a physician. Abrupt discontinuation or incorrect substitution can cause dangerous withdrawal symptoms including seizures.
- What does the optional weight field do?
- When you enter patient weight (in kg or lbs), the calculator additionally shows the equivalent dose expressed as mg per kg and mg per lb body weight, useful for clinical weight-based dosing reference.
⚠️ Medical Disclaimer: This calculator is for educational and informational purposes only. It does not constitute medical advice and cannot replace professional clinical judgment. Benzodiazepine prescribing and switching should only be done under the supervision of a qualified healthcare provider. Always consult your doctor or pharmacist before changing your medication regimen.