Aztreonam

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

Pharmacology

Inhibits bacterial cell wall synthesis.

Pharmacokinetics

Absorption

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.

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

Serum t _½ may be prolonged.

Serum t _½ may be prolonged.

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

IM/IV 500 mg or 1 g every 8 to 12 h.

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

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

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

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

Incompatibility

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

Laboratory Test Interactions

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

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.

Copyright © 2009 Wolters Kluwer Health.