SHEET /vs/diazepam-vs-lorazepam · COMPARISON
Diazepam vs Lorazepam: what is the difference?
How they differ
from source
Both are benzodiazepines and the useful distinction is what the liver has to do with them. Diazepam is broken down through oxidation into several active metabolites, so its effect outlasts the parent molecule and accumulates with repeated use, especially in older people and in anyone with reduced liver function. Lorazepam is conjugated directly and produces no active metabolite, so its effect ends more cleanly, which is why it is often preferred where liver function is a concern. Diazepam is the more fat-soluble of the two and reaches the brain faster, which matters when either is used for an acute seizure. Lorazepam is the heavier at 321.2 against 284.7.
Side by side
| Diazepam | Lorazepam | |
|---|---|---|
| Formula | C16H13ClN2O | C15H10Cl2N2O2 |
| Molecular weight | 284.74 g/mol | 321.2 g/mol |
| Family | Benzodiazepines | Benzodiazepines |
| Everyday group | Prescription medicine | Prescription medicine |
| Functional groups | Aromatics, Amides, Halogenated | Alcohols, Aromatics, Amides, Halogenated |
| GHS signal wordThe supplier-filed hazard label, not a statement about ordinary use. | Danger | Warning |
| Oral LD50A single acute animal measure. It ranks nothing about human safety. | 710 mg/kg (oral, rat) | 3,178 mg/kg (oral, mouse) |
| CAS number | 439-14-5 | 846-49-1 |
| PubChem CID | 3016 | 3958 |
Common questions
- What is the difference between Diazepam and Lorazepam?
- Both are benzodiazepines and the useful distinction is what the liver has to do with them. Diazepam is broken down through oxidation into several active metabolites, so its effect outlasts the parent molecule and accumulates with repeated use, especially in older people and in anyone with reduced liver function. Lorazepam is conjugated directly and produces no active metabolite, so its effect ends more cleanly, which is why it is often preferred where liver function is a concern.
- Is Diazepam bigger than Lorazepam?
- Lorazepam is the heavier molecule, 321.2 g/mol against 284.74 g/mol for Diazepam. Diazepam is C16H13ClN2O and Lorazepam is C15H10Cl2N2O2.
- Which has the lower reported LD50, Diazepam or Lorazepam?
- Diazepam, at 710 mg/kg (oral, rat), against 3,178 mg/kg (oral, mouse) for Lorazepam. 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.