Title: Cilastatin
CAS Registry Number: 82009-34-5
CAS Name: (2Z)-7-[[(2R)-2-Amino-2-carboxyethyl]thio]-2-[[[(1S)-2,2-dimethylcyclopropyl]carbonyl]amino]-2-heptenoic acid
Manufacturers' Codes: MK-791
Molecular Formula: C16H26N2O5S
Molecular Weight: 358.45
Percent Composition: C 53.61%, H 7.31%, N 7.82%, O 22.32%, S 8.95%
Literature References: Prevents renal metabolism of penem and carbapenem antibiotics by specific and reversible dehydropeptidase I inhibition. Synthesis and combination with thienamycins: D. W. Graham et al., EP 48301; H. Kropp et al., EP 48025 (both 1982 to Merck & Co.), C.A. 97, 145271b, 145270a (1982). Combination with penems: F. M. Kahan, H. Kropp, EP 72014 (1983 to Merck & Co.), C.A. 99, 70272h (1983). The articles cited below discuss the activity of cilastatin alone and in combination with imipenem, q.v. Dipeptidase inhibition, pharmacokinetics: S. R. Norrby et al., Antimicrob. Agents Chemother. 23, 300 (1983). Stimulation of granulocyte function: H. Gnarpe et al., ibid. 25, 179 (1984). HPLC determn in serum: C. M. Myers, J. L. Blumer, ibid. 26, 78 (1984). Enhances intrathecal and ocular penetration of imipenem: A. W. Chow et al., ibid. 23, 634 (1983) and K. R. Finlay et al., Invest. Ophthalmol. Visual Sci. 24, 1147 (1983), respectively. In experimental meningitis: D. E. Washburn et al., J. Antimicrob. Chemother. 12, 39 (1983). Series of articles on pharmacokinetics, safety and tolerance and efficacy of cilastatin/imipenem: ibid. 12, Suppl. D, 1-155 (1983); Infection 14, Suppl. 2, S111-S180 (1986).
Derivative Type: Sodium salt
CAS Registry Number: 81129-83-1
Additional Names: Cilastatin sodium
Molecular Formula: C16H25N2NaO5S
Molecular Weight: 380.43
Percent Composition: C 50.51%, H 6.62%, N 7.36%, Na 6.04%, O 21.03%, S 8.43%
Properties: Off-white to yellowish-white hygroscopic, amorphous solid. pKa1 2.0; pKa2 4.4; pKa3 9.2. Very sol in water, methanol.
pKa: pKa1 2.0; pKa2 4.4; pKa3 9.2
Therap-Cat: Antibacterial adjunct (dipeptidase inhibitor).
Keywords: Antibacterial Adjuncts; Renal Dipeptidase Inhibitors.
Cilazapril Ciliary Neurotrophic Factor Cilnidipine Cilomilast Cimaterol

Cilastatin Structural Formulae.png
Cilastatin ball-and-stick.png
Systematic (IUPAC) name
2,2-dimethylcyclopropanecarbonyl]amino}hept-2-enoic acid
Clinical data
AHFS/ International Drug Names
MedlinePlus a686013
Legal status  ?
CAS number 82009-34-5 YesY
ATC code J01DH51 (combination with imipenem)
PubChem CID 5280454
DrugBank DB01597
ChemSpider 4940183 YesY
UNII 141A6AMN38 YesY
KEGG D07698 YesY
Chemical data
Formula C16H26N2O5S 
Mol. mass 358.454 g/mol
 YesY (what is this?)  (verify)

Cilastatin is a chemical compound which inhibits the human enzyme dehydropeptidase.[1]

Dehydropeptidase is an enzyme found in the kidney and is responsible for degrading the antibiotic imipenem. Cilastatin can therefore be combined intravenously with imipenem in order to protect it from dehydropeptidase and prolong its antibacterial effect. Imipenem alone is an effective antibiotic and can be given without the cilastatin. Cilastatin itself does not have antibiotic activity.

Another carbapenem, meropenem is resistant to dehydropeptidase; therefore, it can be given without cilastatin.