Erythromycin

Erythromycin
	Above: Erythromycin A molecular structure Below: 3D representation of an erythromycin A molecule
Clinical data
Trade names	Eryc, Erythrocin, others
AHFS/Drugs.com	Monograph
MedlinePlus	a682381
License data	US DailyMed: Erythromycin;
Pregnancy; category	AU: A;
Routes of; administration	By mouth, intravenous, intramuscular, topical, eye drops
Drug class	Macrolide antibiotic
ATC code	D10AF02 (WHO) J01FA01 (WHO) S01AA17 (WHO) QJ51FA01 (WHO);
Legal status
Legal status	AU: S4 (Prescription only); UK: POM (Prescription only); US: ℞-only;
Pharmacokinetic data
Bioavailability	Depends on the ester type; between 30% and 65%
Protein binding	90%
Metabolism	Liver (under 5% excreted unchanged)
Elimination half-life	1.5 hours
Excretion	Bile
Identifiers
	IUPAC name (3R,4S,5S,6R,7R,9R,11R,12R,13S,14R)-6-{[(2S,3R,4S,6R)-4-(Dimethylamino)-3-hydroxy-6-methyloxan-2-yl]oxy}-14-ethyl-7,12,13-trihydroxy-4-{[(2R,4R,5S,6S)-5-hydroxy-4-methoxy-4,6-dimethyloxan-2-yl]oxy}-3,5,7,9,11,13-hexamethyl-1-oxacyclotetradecane-2,10-dione;
CAS Number	114-07-8 ;
PubChem CID	12560;
IUPHAR/BPS	1456;
DrugBank	DB00199 ;
ChemSpider	12041 ;
UNII	63937KV33D;
KEGG	D00140 ;
ChEBI	CHEBI:42355 ;
ChEMBL	ChEMBL532 ;
PDB ligand	ERY (PDBe, RCSB PDB);
CompTox Dashboard (EPA)	DTXSID4022991 ;
ECHA InfoCard	100.003.673
Chemical and physical data
Formula	C37H67NO13
Molar mass	733.937 g·mol−1
	SMILES CC[C@@H]1[C@@]([C@@H]([C@H](C(=O)[C@@H](C[C@@]([C@@H]([C@H]([C@@H]([C@H](C(=O)O1)C)O[C@H]2C[C@@]([C@H]([C@@H](O2)C)O)(C)OC)C)O[C@H]3[C@@H]([C@H](C[C@H](O3)C)N(C)C)O)(C)O)C)C)O)(C)O;
	InChI InChI=1S/C37H67NO13/c1-14-25-37(10,45)30(41)20(4)27(39)18(2)16-35(8,44)32(51-34-28(40)24(38(11)12)15-19(3)47-34)21(5)29(22(6)33(43)49-25)50-26-17-36(9,46-13)31(42)23(7)48-26/h18-26,28-32,34,40-42,44-45H,14-17H2,1-13H3/t18-,19-,20+,21+,22-,23+,24+,25-,26+,28-,29+,30-,31+,32-,34+,35-,36-,37-/m1/s1 ; Key:ULGZDMOVFRHVEP-RWJQBGPGSA-N ;
	(verify)

Erythromycin is an antibiotic used for the treatment of a number of bacterial infections. This includes respiratory tract infections, skin infections, chlamydia infections, pelvic inflammatory disease, and syphilis. It may also be used during pregnancy to prevent Group B streptococcal infection in the newborn, and to improve delayed stomach emptying. It can be given intravenously and by mouth. An eye ointment is routinely recommended after delivery to prevent eye infections in the newborn.

Common side effects include abdominal cramps, vomiting, and diarrhea. More serious side effects may include Clostridioides difficile colitis, liver problems, prolonged QT, and allergic reactions. It is generally safe in those who are allergic to penicillin. Erythromycin also appears to be safe to use during pregnancy. While generally regarded as safe during breastfeeding, its use by the mother during the first two weeks of life may increase the risk of pyloric stenosis in the baby. This risk also applies if taken directly by the baby during this age. It is in the macrolide family of antibiotics and works by decreasing bacterial protein production.

Erythromycin was first isolated in 1952 from the bacteria Saccharopolyspora erythraea. It is on the World Health Organization's List of Essential Medicines. In 2022, it was the 271st most commonly prescribed medication in the United States, with more than 800,000 prescriptions.