Imipenem

Imipenem

Clinical data
Trade names	Primaxin
AHFS/Drugs.com	International Drug Names
MedlinePlus	a686013
License data	US DailyMed: Imipenem
Pregnancy category	AU: B3
Routes of administration	IM, IV
ATC code	J01DH51 (WHO)
Legal status
Legal status	AU: S4 (Prescription only) CA: ℞-only UK: POM (Prescription only) US: ℞-only
Pharmacokinetic data
Protein binding	20%
Metabolism	Renal
Elimination half-life	38 minutes (children), 60 minutes (adults)
Excretion	Urine (70%)
Identifiers
IUPAC name (5R,6S)-6-[(1R)-1-hydroxyethyl]-3-({2-[(iminomethyl)amino]ethyl}thio)-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid
CAS Number	64221-86-9
PubChem CID	104838
DrugBank	DB01598
ChemSpider	4445535
UNII	Q20IM7HE75
KEGG	D04515
ChEBI	CHEBI:51799
ChEMBL	ChEMBL43708
PDB ligand	IM2 (PDBe, RCSB PDB)
CompTox Dashboard (EPA)	DTXSID2023143
ECHA InfoCard	100.058.831
Chemical and physical data
Formula	C12H17N3O4S
Molar mass	299.35 g·mol−1
3D model (JSmol)	Interactive image
SMILES O=C(O)/C1=C(\SCC/N=C/N)C[C@H]2N1C(=O)[C@@H]2[C@H](O)C.O
InChI InChI=1S/C12H17N3O4S.H2O/c1-6(16)9-7-4-8(20-3-2-14-5-13)10(12(18)19)15(7)11(9)17;/h5-7,9,16H,2-4H2,1H3,(H2,13,14)(H,18,19);1H2/t6-,7-,9-;/m1./s1  Key:GSOSVVULSKVSLQ-JJVRHELESA-N
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Imipenem (trade name Primaxin among others) is a synthetic β-lactam antibiotic belonging to the carbapenems chemical class. developed by Merck scientists Burton Christensen, William Leanza, and Kenneth Wildonger in the mid-1970s. Carbapenems are highly resistant to the β-lactamase enzymes produced by many multiple drug-resistant Gram-negative bacteria, thus playing a key role in the treatment of infections not readily treated with other antibiotics. It is usually administered through intravenous injection.

Imipenem was patented in 1975 and approved for medical use in 1985. It was developed via a lengthy trial-and-error search for a more stable version of the natural product thienamycin, which is produced by the bacterium Streptomyces cattleya. Thienamycin has antibacterial activity, but is unstable in aqueous solution, thus it is practically of no medicinal use. Imipenem has a broad spectrum of activity against aerobic and anaerobic, Gram-positive and Gram-negative bacteria. It is particularly important for its activity against Pseudomonas aeruginosa and Enterococcus species. However, it is not active against MRSA.

Medical uses

Spectrum of bacterial susceptibility and resistance

Acinetobacter anitratus, Acinetobacter calcoaceticus, Actinomyces odontolyticus, Aeromonas hydrophila, Bacteroides distasonis, Bacteroides uniformis, and Clostridium perfringens are generally susceptible to imipenem, while Acinetobacter baumannii, some Acinetobacter spp., Bacteroides fragilis, and Enterococcus faecalis have developed resistance to imipenem to varying degrees. Not many species are resistant to imipenem except Pseudomonas aeruginosa (Oman) and Stenotrophomonas maltophilia.

Coadministration with cilastatin

Imipenem is rapidly degraded by the renal enzyme dehydropeptidase 1 when administered alone, and is almost always coadministered with cilastatin to prevent this inactivation.

Adverse effects

Common adverse drug reactions are nausea and vomiting. People who are allergic to penicillin and other β-lactam antibiotics should take caution if taking imipenem, as cross-reactivity rates are high. At high doses, imipenem is seizurogenic.

Mechanism of action

Imipenem acts as an antimicrobial through inhibiting cell wall synthesis of various Gram-positive and Gram-negative bacteria. It remains very stable in the presence of β-lactamase (both penicillinase and cephalosporinase) produced by some bacteria, and is a strong inhibitor of β-lactamases from some Gram-negative bacteria that are resistant to most β-lactam antibiotics.