Imipenem/Cilastatin

A to Z Drug Facts

Imipenem/Cilastatin

	Action
	Indications
	Contraindications
	Route/Dosage
	Interactions
	Lab Test Interferences
	Adverse Reactions
	Precautions
Patient Care Considerations
	Administration/Storage
	Assessment/Interventions
	Patient/Family Education

(ih-mih-PEN-em-SIGH-luh-STAT-in)

Primaxin IV, Primaxin IM

Class: Anti-infective/Carbapenem

Action Imipenem inhibits bacterial cell wall synthesis. Cilastatin prevents metabolism of imipenem, resulting in increased urinary recovery and decreased renal toxicity.

Indications Treatment of serious infections of lower respiratory tract and urinary tract, intra-abdominal and gynecologic infections, bacterial septicemia, bone and joint infections, skin and skin structure infections, endocarditis, and polymicrobic infections due to susceptible microorganisms.

Contraindications IM use with hypersensitivity to local anesthetics of amide type or with severe shock or heart block. IV use with patients with meningitis (safety and efficacy have not been established).

Route/Dosage

ADULTS: IV 125, 250, or 500 mg dose over 20 to 30 min. Infuse a 750 mg or 1 g dose over 40 to 60 min. If nausea develops, slow the infusion rate. Max: 50 mg/kg/day or 4 g/day, whichever is lower. ADULTS: IM 500 to 750 mg q 12 hr. Max: 1500 mg/day. CHILDREN < 40 kg: IM 60 mg/kg/day. CHILDREN ³ 40 kg: IM Adult dose. PREMATURE INFANTS (³ 36 WK GESTATIONAL AGE): IM 20 mg/kg q 12 hr.

Interactions Cyclosporine: CNS side effects (eg, myoclonia, seizures) may be increased. Ganciclovir: Generalized seizures may occur; avoid use. Probenecid: Minimal increases in imipenem levels and half-life; do not give probenecid concurrently. INCOMPATIBILITIES: Do not physically mix imipenem-cilastatin with other antibiotics.

Lab Test Interferences May cause positive Coombs' test results.

Adverse Reactions

CV: Hypotension; palpitations; tachycardia; phlebitis; thrombophlebitis. CNS: Seizures. GI: Nausea; diarrhea; vomiting; pseudomembranous colitis; hemorrhagic colitis; hepatitis. GU: Presence of RBCs, WBCs, casts and bacteria in urine; increased BUN and creatinine. HEMA: Decreased Hgb and Hct; eosinophilia; increased or decreased WBCs and platelets; decreased erythrocytes. HEPA: Increased AST, ALT, alkaline phosphatase, and bilirubin. OTHER: Pain at injection site.

Precautions

Pregnancy: Category C. Lactation: Undetermined. Children: Safety and efficacy in children < 12 yr not established with IM use. IV use in neonates to 16 yr (with non-CNS infections) is supported by evidence from adequate and well-controlled studies. IV use is not recommended in pediatric patients with CNS infections because of the risk of seizures, or in pediatric patients < 30 kg with impaired renal function as no data are available. Benzyl alcohol: as a preservative has been associated with toxicity in neonates, especially those < 3 mo. Do not use diluents containing benzyl alcohol when IV is constituted for adminstration to pediatric patients. CNS: IV administration may result in myoclonic activity confusional states or seizures. Hypersensitivity: Administer drug with caution to penicillin-sensitive patients due to possible cross-activity. Pseudomembranous colitis: Consider possibility in patients with diarrhea. Renal impairment: Dosage reduction or alteration of dosage interval is required. Superinfection: May result in bacterial or fungal overgrowth of nonsusceptible organisms.

PATIENT CARE CONSIDERATIONS

Administration/Storage

Do not inject by direct IV bolus.
For IV administration, reconstitute with 100 ml of compatible diluent. Shake until suspension is clear; add suspension to 100 ml of appropriate infusion solution. Then add 10 ml of infusion to vial; shake well to ensure that all medication is used and transfer resulting suspension to infusion solution. Color of solution may range from colorless to yellow. Solution is stable for 4 hr at room temperature and for 24 hr when refrigerated. Do not administer if solution is cloudy.
Do not mix with or physically add to antibiotics. However, if may be administered concomitantly with other antibiotics (eg, aminoglycosides).
Do not use IM preparation for IV administration.
For IM administration, prepare with 1% lidocaine hydrochloride solution (without epinephrine). Prepare 500 mg vial with 2 ml and 750 mg vial with 3 ml of lidocaine. Agitate to form suspension. Color of solution may range from white to light tan. Withdraw and inject entire contents of vial IM. Use within 1 hr of preparation.
Store unreconstituted powder < 77°F.

Assessment/Interventions

Obtain complete patient history, including drug history and any known allergies, especially to penicillin and beta-lactam antibiotics.
Notify physician if signs of superinfection or resistance occur.
Have epinephrine, antihistamines, and resuscitation equipment available in case of anaphylaxis.
If seizure occurs, withhold drug, institute safety measures, and notify physician.
If culture and sensitivity is ordered, obtain specimen prior to first dose.
Withhold drug and notify physician if any of following occurs: Fever, rash, hives, difficulty breathing, vaginitis, or severe diarrhea.
Monitor vital signs, sputum, urine, stool, and WBC at beginning of and throughout therapy.

OVERDOSAGE: SIGNS & SYMPTOMS
	Seizures

Patient/Family Education

Instruct patient to report the following to physician or nurse: Itching; rash; hives; difficulty breathing; diarrhea; black “furry” tongue; loose, foul-smelling stools; or vaginal itching or discharge.