Alprazolam vs Diazepam: what is the difference?
Alprazolam acts fast and clears fast, while diazepam persists far longer through active metabolites that can stretch its effect over days.
Sources and notes
- The sentence under the titlefrom sourceMoleculeFinder comparison notesThe pair's answer line.
- The two drawingscomputedMoleculeFinder rule (RDKit MCS)Drawn the same way round on the skeleton they share. Aligned; 6 atoms differ, too many to mark as one group.
- Structural similaritycomputedRDKit Morgan/Tanimoto0.58 of 1, a Morgan fingerprint Tanimoto coefficient. It measures shape, not effect.
Side by side
| Alprazolam | Diazepam | |
|---|---|---|
| Molecular weightCalculated PubChem | 308.8 g/molC17H13ClN4 | 284.74 g/molC16H13ClN2O |
| Hydrogen-bond donorsCalculated PubChem | 0 | 0 |
| FamilyEditorial MoleculeFinder curated | Benzodiazepines | Benzodiazepines |
| Everyday groupEditorial MoleculeFinder curated | Prescription medicine | Prescription medicine |
| Chemical groupsCalculated Found by rule (RDKit) | Aromatics, Halogenated | Aromatics, Amides, Halogenated |
| Hazard labelReported ECHA, HSDB via PubChem; ECHA via PubChem | Warning | Danger |
| The supplier-filed hazard label's signal word, not a statement about ordinary use. | ||
| Oral LD50Measured HSDB via PubChem | 1,220 mg/kgpure alprazolam, rat, oral | 710 mg/kgpure diazepam, rat, oral |
| A single acute animal measure. It ranks nothing about human safety. | ||
Sources and notes
- Molecular weightcomputedPubChemComputed from the structure; the formula is under each weight.
- Hydrogen-bond donorscomputedPubChemThe hydrogens on nitrogen or oxygen that each molecule can lend to a hydrogen bond, counted from its structure.
- Familyfrom sourceMoleculeFinder curated
- Everyday groupfrom sourceMoleculeFinder curated
- Chemical groupscomputedFound by rule (RDKit)Each group is found in the structure by a chemical pattern.
- Hazard labelfrom sourceECHA, HSDB via PubChem; ECHA via PubChem
- Oral LD50from sourceHSDB via PubChem
- ECHAfrom sourceAttributionSource: European Chemicals Agency, echa.europa.eu.
- Identifiersfrom sourcePubChemPubChem CID 2118 (Alprazolam) and 3016 (Diazepam).
In more detail
Both are benzodiazepines and both work by making the brain's own GABA more effective at its receptor. Alprazolam acts fast and clears fast, with a half-life around 11 hours, which is why it is associated with acute panic and also with a sharper rebound as it leaves. Diazepam is absorbed very quickly but persists far longer, and it produces long-lived active metabolites including nordazepam that can stretch its effect over days. That is why diazepam is used to taper other benzodiazepines and alprazolam is not. Alprazolam is the more potent per unit weight by a wide margin. Structurally alprazolam carries a triazole ring fused to the benzodiazepine core that diazepam lacks.
Sources and notes
- The paragraphfrom sourceMoleculeFinder comparison notes
Questions
- What is the difference between Alprazolam and Diazepam?
- Alprazolam acts fast and clears fast, while diazepam persists far longer through active metabolites that can stretch its effect over days.
- Is Alprazolam bigger than Diazepam?
- Alprazolam is the heavier molecule, 308.8 g/mol against 284.74 g/mol for Diazepam. Alprazolam is C17H13ClN4 and Diazepam is C16H13ClN2O.
- Which has the lower reported LD50, Alprazolam or Diazepam?
- Diazepam, at 710 mg/kg (oral, rat), against 1,220 mg/kg (oral, rat) for Alprazolam. An LD50 is one acute animal measurement, and the two here were not necessarily measured in the same species, so it is a data point rather than a ranking of how dangerous either is to a person.
Sources and notes
- The answersfrom sourceMoleculeFinderThe first is the pair's answer line; the others are read off the table above.