|Pregnancy cat.||C (US)|
|Legal status||POM (UK) ℞-only (US)|
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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.
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 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).
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
- Stomach pain
Major side effects requiring medical attention:
- Facial swelling
- Difficulty breathing
- Unusual bleeding
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.
- 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.
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.
- "Primaxin I.V.". RxList. Retrieved January 25, 2013.
- "Primaxin IM". RxList. Retrieved January 25, 2013.
- "Imipenem and Cilastatin Sodium Injection". Medline Plus. Retrieved January 25, 2013.
- "Primaxin IM-Missed dose". RxList. Retrieved January 25, 2013.