Clonazepam vs Alprazolam: what is the difference?
Clonazepam lasts far longer than alprazolam, a half-life of 30 to 40 hours against about 11, so it is used for seizures and alprazolam for acute episodes.
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; 10 atoms differ, too many to mark as one group.
Side by side
| Clonazepam | Alprazolam | |
|---|---|---|
| Molecular weightCalculated PubChem | 315.71 g/molC15H10ClN3O3 | 308.8 g/molC17H13ClN4 |
| Hydrogen-bond donorsCalculated PubChem | 1 | 0 |
| FamilyEditorial MoleculeFinder curated | Benzodiazepines | Benzodiazepines |
| Everyday groupEditorial MoleculeFinder curated | Prescription medicine | Prescription medicine |
| Chemical groupsCalculated Found by rule (RDKit) | Aromatics, Amides, Halogenated | Aromatics, Halogenated |
| Hazard labelReported ECHA via PubChem; ECHA, HSDB via PubChem | Danger | Warning |
| The supplier-filed hazard label's signal word, not a statement about ordinary use. | ||
| Oral LD50Measured HSDB via PubChem | 15,000 mg/kgpure clonazepam, rat, oral | 1,220 mg/kgpure alprazolam, 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 via PubChem; ECHA, HSDB via PubChem
- Oral LD50from sourceHSDB via PubChem
- ECHAfrom sourceAttributionSource: European Chemicals Agency, echa.europa.eu.
- Identifiersfrom sourcePubChemPubChem CID 2802 (Clonazepam) and 2118 (Alprazolam).
In more detail
Both are high-potency benzodiazepines with a triazolo or nitro group that sets them apart from the older members of the class, and both act on the same GABA-A receptor. Clonazepam lasts substantially longer, with a half-life in the range of 30 to 40 hours against alprazolam's 11, which is why it is used for seizure disorders and long-acting anxiety control where alprazolam is used for acute episodes. The shorter action of alprazolam is also why it is the more associated with between-dose rebound. Both are controlled substances in the US and in most of Europe. Clonazepam carries a nitro group and a chlorine at 315.7; alprazolam has the triazole ring at 308.8.
Sources and notes
- The paragraphfrom sourceMoleculeFinder comparison notes
Questions
- What is the difference between Clonazepam and Alprazolam?
- Clonazepam lasts far longer than alprazolam, a half-life of 30 to 40 hours against about 11, so it is used for seizures and alprazolam for acute episodes.
- Is Clonazepam bigger than Alprazolam?
- Clonazepam is the heavier molecule, 315.71 g/mol against 308.8 g/mol for Alprazolam. Clonazepam is C15H10ClN3O3 and Alprazolam is C17H13ClN4.
- Which has the lower reported LD50, Clonazepam or Alprazolam?
- Alprazolam, at 1,220 mg/kg (oral, rat), against 15,000 mg/kg (oral, rat) for Clonazepam. 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.