Doxycycline vs Azithromycin: what is the difference?
Doxycycline and azithromycin both block bacterial protein making, but azithromycin is far larger and lingers in tissue, which is why its courses are short.
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, 4 of 52 atoms, is too small to align on.
Side by side
| Doxycycline | Azithromycin | |
|---|---|---|
| Molecular weightCalculated PubChem | 444.4 g/molC22H24N2O8 | 749 g/molC38H72N2O12 |
| Hydrogen-bond donorsCalculated PubChem | 6 | 5 |
| FamilyEditorial MoleculeFinder curated | Antibiotics | Antibiotics |
| Everyday groupEditorial MoleculeFinder curated | Prescription medicine | Prescription medicine |
| Chemical groupsCalculated Found by rule (RDKit) | Alcohols, Aromatics, Ketones, Amides, Phenols | Alcohols, Esters, Ethers |
| Hazard labelReported ECHA via PubChem | Not recorded | Danger |
| The supplier-filed hazard label's signal word, not a statement about ordinary use. | ||
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
- ECHAfrom sourceAttributionSource: European Chemicals Agency, echa.europa.eu.
- Identifiersfrom sourcePubChemPubChem CID 54671203 (Doxycycline) and 447043 (Azithromycin).
In more detail
They bind different parts of the ribosome. Doxycycline is a tetracycline and blocks the 30S subunit; azithromycin is a macrolide and blocks the 50S. Both penetrate tissue well and both cover the atypical organisms that cell-wall antibiotics miss, which is why they overlap in respiratory and sexually transmitted infections. Doxycycline causes photosensitivity and stains developing teeth, which is why it is avoided in young children, and azithromycin does not. Azithromycin is the much larger molecule at 749.0 against 444.4, and its very long tissue half-life is why courses are short.
Sources and notes
- The paragraphfrom sourceMoleculeFinder comparison notes
Questions
- What is the difference between Doxycycline and Azithromycin?
- Doxycycline and azithromycin both block bacterial protein making, but azithromycin is far larger and lingers in tissue, which is why its courses are short.
- Is Doxycycline bigger than Azithromycin?
- Azithromycin is the heavier molecule, 749 g/mol against 444.4 g/mol for Doxycycline. Doxycycline is C22H24N2O8 and Azithromycin is C38H72N2O12.
Sources and notes
- The answersfrom sourceMoleculeFinderThe first is the pair's answer line; the others are read off the table above.