Loratadine vs Diphenhydramine: what is the difference?
Diphenhydramine, sold as Benadryl, enters the brain and causes drowsiness for a few hours, while loratadine, sold as Claritin, stays out and lasts a full day.
Sources and notes
- The sentence under the titlefrom sourceMoleculeFinder comparison notesThe pair's answer line.
- The two drawingscomputedMoleculeFinder rule (RDKit MCS)Each molecule's own drawing, as its page shows it. The common core, 6 of 27 atoms, is too small to align on.
Side by side
| Loratadine | Diphenhydramine | |
|---|---|---|
| Molecular weightCalculated PubChem | 382.9 g/molC22H23ClN2O2 | 255.35 g/molC17H21NO |
| Hydrogen-bond donorsCalculated PubChem | 0 | 0 |
| Where each turns upEditorial MoleculeFinder food and product lists | Not on our lists |
|
| Also sold asEditorial MoleculeFinder curated | Claritin, Alavert | Benadryl, ZzzQuil, Sominex |
| FamilyEditorial MoleculeFinder curated | Over-the-counter medicines | Over-the-counter medicines |
| Everyday groupEditorial MoleculeFinder curated | OTC medicine | OTC medicine |
| Chemical groupsCalculated Found by rule (RDKit) | Aromatics, Esters, Halogenated | Aromatics, Ethers |
| Hazard labelReported ECHA via PubChem | Danger | Warning |
| The supplier-filed hazard label's signal word, not a statement about ordinary use. | ||
| Oral LD50Measured HSDB via PubChem | 5,000 mg/kgpure loratadine, rat, oral | Not recorded |
| 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.
- Where each turns upfrom sourceMoleculeFinder food and product listsEach amount is an editorial figure from our lists, not a measurement of any one product. Each mark is set by hand on the list, never inferred.
- Also sold asfrom sourceMoleculeFinder curated
- 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
- Oral LD50from sourceHSDB via PubChem
- ECHAfrom sourceAttributionSource: European Chemicals Agency, echa.europa.eu.
- Identifiersfrom sourcePubChemPubChem CID 3957 (Loratadine) and 3100 (Diphenhydramine).
In more detail
This is the Claritin and Benadryl comparison, and it is the clearest example of what separates antihistamine generations. Diphenhydramine is a small, fat-soluble first generation molecule that crosses into the brain easily, which is why it works within an hour and reliably causes drowsiness, and why it doubles as a sleep aid. Loratadine is built to stay out of the brain, so it is non-sedating for most people, but it lasts a full day where diphenhydramine's effect fades in a few hours. Diphenhydramine also blocks acetylcholine receptors, which is where the dry mouth and blurred vision come from, and loratadine largely does not. Loratadine is much the heavier molecule at 382.9 against 255.35.
Sources and notes
- The paragraphfrom sourceMoleculeFinder comparison notes
Questions
- What is the difference between Loratadine and Diphenhydramine?
- Diphenhydramine, sold as Benadryl, enters the brain and causes drowsiness for a few hours, while loratadine, sold as Claritin, stays out and lasts a full day.
- Is Loratadine bigger than Diphenhydramine?
- Loratadine is the heavier molecule, 382.9 g/mol against 255.35 g/mol for Diphenhydramine. Loratadine is C22H23ClN2O2 and Diphenhydramine is C17H21NO.
Sources and notes
- The answersfrom sourceMoleculeFinderThe first is the pair's answer line; the others are read off the table above.