DrugindexOnline^{2nd edition}

Pronouncation: (AZZ-TREE-oh-nam)
Class: Monobactam

Trade Names:
Azactam
- Powder for injection (lyophilized cake) 500 mg (with approximately 780 mg L-arginine per gram aztreonam)
- Powder for injection (lyophilized cake) 1 g (with approximately 780 mg L-arginine per gram aztreonam)
- Powder for injection (lyophilized cake) 2 g (with approximately 780 mg L-arginine per gram aztreonam)
- Solution for injection 1 g per 50 mL
- Solution for injection 2 g per 50 mL

Mechanism of Action

Pharmacology

Inhibits bacterial cell wall synthesis.

Pharmacokinetics

Absorption

IV

C _max is 54 mcg/mL (500 mg dose), 90 mcg/mL (1 g dose); and 204 mcg/mL (2 g dose) immediately after administration.

IM

T _max is approximately 1 h; produces comparable serum concentrations to IV doses.

Distribution

Vd is approximately 12.6 L; approximately 56% protein bound. Widely distributed to fluids and tissues, including CSF (inflamed meninges) and breast milk; crosses placenta.

Elimination

The t _½ is approximately 1.7 h; serum clearance is 91 mL/min; renal clearance is 56 mL/min; 60% to 70% is recovered in the urine by 8 h; approximately 12% recovered in the feces.

Special Populations

Renal Function Impairment

Serum t _½ may be prolonged.

Hepatic Function Impairment

Serum t _½ may be prolonged.

Elderly

Serum t _½ may be prolonged.

Indications and Usage

Treatment of infections of urinary tract, lower respiratory tract, skin and skin structure, intra-abdominal infections, gynecologic infections, surgical infections, and septicemia caused by susceptible microorganisms.

Unlabeled Uses

Treatment of acute, uncomplicated gonorrhea in patients with penicillin-resistant gonococci.

Contraindications

Standard considerations.

Dosage and Administration

UTI
Adults

IM/IV 500 mg or 1 g every 8 to 12 h.

Systemic Infections
Adults

IM/IV 1 to 2 g every 6 to 12 h.

Children

IM/IV 30 to 50 mg/kg every 4 to 8 h.

Acute Uncomplicated Gonorrhea

IM 1 g. Max recommended dosage is 8 g/day.

Storage/Stability

Shake reconstituted solutions vigorously immediately after mixing. Reconstituted solutions not exceeding 2% are stable at room temperature for 48 h; stable under refrigeration for 7 days. Discard unused solutions. See the prescribing information for further storage and incompatibility information. Frozen infusion solutions may be stored for up to 3 mo at −4°F.

Drug Interactions

Beta-lactamase–inducing antibiotics (eg, cefoxitin, imipenem)

May antagonize activity of aztreonam and should not be used concurrently.

Incompatibility

Nafcillin sodium, cephradine, and metronidazole are incompatible in admixture.

Laboratory Test Interactions

Children

15% to 20% of patients had elevations of AST and ALT more than 3 times the ULN.

Adverse Reactions

Dermatologic

Rash.

CNS

Seizures.

GI

Diarrhea; nausea; vomiting; pseudomembranous colitis.

Respiratory

Dyspnea.

Miscellaneous

Phlebitis/thrombophlebitis after IV administration; pain/swelling at IM injection site; fever.

Precautions

Monitor Review culture and sensitivity of organism as available.

Pregnancy

Category B .

Lactation

Excreted in breast milk.

Children

Safety and efficacy in children younger than 9 mo of age not established.

Hypersensitivity

Reactions range from mild to life-threatening. Administer cautiously to penicillin- or cephalosporin-sensitive patients because of possible cross-reactivity.

Renal Function

Reduced dose required.

Superinfection

May result in overgrowth of nonsusceptible bacterial or fungal organisms.

Patient Information

• Encourage patient to increase fluid intake to 2,000 to 3,000 mL/day, if allowed.
• Inform patient to notify health care provider if rash or difficulty breathing is experienced.
• If therapy is discontinued because of allergic reaction, explain significance of penicillin allergy and of potential problems with cephalosporins.
• Caution patient against skipping doses or stopping treatment early, which could result in recurrence of symptoms and potential resistance of the organism to this product.