SHEET /vs/loratadine-vs-cetirizine · COMPARISON
Loratadine vs Cetirizine: what is the difference?
How they differ
from source
Both are second generation antihistamines taken once a day and both block the H1 receptor. Cetirizine crosses into the brain slightly more than loratadine does, so it is a little more likely to cause drowsiness while also tending to act faster and more strongly on symptoms. Loratadine is a prodrug in effect: the liver converts much of it to desloratadine, which is what does most of the work, and that adds a step cetirizine does not have. Cetirizine is the heavier molecule at 388.9 against 382.9 and carries a carboxylic acid where loratadine carries a carbamate ester. Both are sold over the counter in most countries.
Side by side
| Loratadine | Cetirizine | |
|---|---|---|
| Formula | C22H23ClN2O2 | C21H25ClN2O3 |
| Molecular weight | 382.9 g/mol | 388.9 g/mol |
| Family | Over-the-counter medicines | Over-the-counter medicines |
| Everyday group | OTC medicine | OTC medicine |
| Functional groups | Aromatics, Esters, Halogenated | Carboxylic Acids, Aromatics, Ethers, 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. | 5,000 mg/kg (oral, rat) | not recorded |
| Also sold as | Claritin, Alavert | Zyrtec |
| CAS number | 79794-75-5 | 83881-51-0 |
| PubChem CID | 3957 | 2678 |
Common questions
- What is the difference between Loratadine and Cetirizine?
- Both are second generation antihistamines taken once a day and both block the H1 receptor. Cetirizine crosses into the brain slightly more than loratadine does, so it is a little more likely to cause drowsiness while also tending to act faster and more strongly on symptoms. Loratadine is a prodrug in effect: the liver converts much of it to desloratadine, which is what does most of the work, and that adds a step cetirizine does not have.
- Is Loratadine bigger than Cetirizine?
- Cetirizine is the heavier molecule, 388.9 g/mol against 382.9 g/mol for Loratadine. Loratadine is C22H23ClN2O2 and Cetirizine is C21H25ClN2O3.
Read the full records: Loratadine and Cetirizine.