Imipenem/cilastatin

Imipenem/cilastatin

Combination of
Imipenem	Carbapenem antibiotic
Cilastatin	Dehydropeptidase inhibitor
Clinical data
MedlinePlus	a605011
Pregnancy cat.	C (US)
Legal status	POM (UK) ℞-only (US)
Routes	Intravenous, intramuscular
Identifiers
CAS number	92309-29-0
ATC code	J01DH51
PubChem	CID 11954222
ChemSpider	21106325 Y
ChEMBL	CHEMBL296854 Y
Y (what is this?)  (verify)

Imipenem/cilastatin (marketed as Primaxin in the USA, and as Tinaxin in India) is a broad spectrum beta-lactam antibiotic containing equal quantities of imipenem and cilastatin. It is related to the penicillin/cephalosporin family of antibiotics but is classified as belonging to the carbapenem class.

Mechanism

It has the ability to kill a wide variety of bacteria. It works by interfering with their ability to form cell walls, and therefore the bacteria break up and die.

• Imipenem, the active antibiotic agent, is rapidly degraded by the renal enzyme dehydropeptidase if administered alone (making it less effective); the metabolites can cause kidney damage.

Availability and description

Primaxin IV is a combination of imipenem, cilastatin sodium and sodium bicarbonate which is added as a buffer. Primaxin IM lacks the sodium bicarbonate buffer.

Indications

Primaxin is indicated in: lower respiratory tract infections (IV, IM), urinary tract infections (IV), intra-abdominal infections (IV, IM), gynecologic infections (IV, IM), bacterial septicemia (IV), bone and joint infections (IV), skin and skin structure infections (IV, IM), endocarditis (IV) and polymicrobic infections (IV).

Precautions

Patients who are allergic to penicillin, cephalosporins and related drugs should tell their doctor. It is important tell your doctor or pharmacist your medical history, especially of: brain disorders (e.g., seizures, head injury, tumor), kidney disease, liver disease, stomach/intestinal diseases (e.g., colitis).

Dosage and administration

The dosage for Primaxin IV in adults is 125 mg, 250 mg, or 500 mg (of each drug) over 20–30 minutes. Each 750 mg or 1000 mg dose should be infused over 40–60 minutes. Primaxin IM given for intra-abdominal infections may be dosed at 750 mg every 12 hours. Other infections may be treated with 500 mg or 750 mg administered every 12 hours depending on its severity.

Side effects

Common side effects for both forms are:

• Upset stomach
• Vomiting
• Stomach pain

Major side effects requiring medical attention:

• Diarrhea
• Rash
• Fever
• Facial swelling
• Difficulty breathing
• Unusual bleeding
• Seizures

This medicine is passed through breast milk so its usage during pregnancy or breast feeding should only be done when clearly needed. Primaxin is cleared from the body via the kidneys so it is important to tell your doctor about any other drugs you take that are also cleared through the kidneys (such as other antibiotics), espcially for older patients as kidney function declines with age.

Interactions

• valproic acid (Depakene, Stavzor)
• ganciclovir (Cytovene)
• probenecid (Benemid)
• penicillin antibiotics such as amoxicillin (Amoxil, Augmentin), ampicillin (Omnipen, Principen), dicloxacillin (Dycill, Dynapen), oxacillin (Bactocill), or penicillin (Beepen-VK, Ledercillin VK, Pen-V, Pen-Vee K, Pfizerpen, V-Cillin K, Veetids, and others); or
• cephalosporin antibiotics such as cefaclor (Ceclor), cefuroxime (Ceftin), cefadroxil (Duricef), cephalexin (Keflex), and others.

Marketing

Imipenem/cilastatin is marketed by Merck & Co. under the trade names Primaxin, Tienam and Zienam. The combination is also marketed by Ranbaxy Laboratories & BIOCON in India under the brand name Cilanem and IMICELUM respectively, as well as by New Medicon Pharma under the brand name Tinaxin and Lupin as Lupinem. It is also marketed by Highnoon Laboratories Ltd. in Pakistan under the trade name Prepenem. Prepenem was launched by Highnoon in May 2007 and was the first generic brand after the research brand Tienam.