Monobactams

Monobactams are beta lactam antibiotics that are bactericidal in action. Currently, the only monobactam available is aztreonam.

Pregnancy Category: B

Animal studies have not shown any effects on the fetus.

Mechanism of Action

Aztreonam is bactericidal. It Interferes with bacterial cell wall synthesis, causing cell death in susceptible gram-negative bacteria. However, it is ineffective against gram-positive and anaerobic bacteria.

Indications

• Used in the treatment of UTIs, lower respiratory infections, skin and skin-structure infections, septicemia, intra-abdominal infections and gynecologic infections caused by susceptible strains of Escherichia coli, Enterobacter, Serratia, Proteus, Salmonella, Providencia, Pseudomonas, Citrobacter, Haemophilus, Neisseria, and Klebsiella.
• Adjunct to surgery in managing infections caused by susceptible organisms.
• Improvement of respiratory symptoms in cystic fibrosis patients with Pseudomonas aeruginosa infections.
• Unlabeled use: 1 g IM for treatment of acute uncomplicated gonorrhea as alternative to spectinomycin in penicillin-resistant gonococci.

Cautions and Contraindications

• Use cautiously in patients with immediate hypersensitivity reaction to penicillin or cephalosporins, renal and hepatic disorders, lactation.
• Contraindicated in patients allergic to aztreonam.

Adverse Effects

• Dermatologic: Rash, pruritus
• GI: Nausea, vomiting, diarrhea, transient elevation of AST, ALT, LDH
• Respiratory: Bronchospasm, cough, congestion, sore throat, wheezing (inhaled form)
• Hypersensitivity: Anaphylaxis
• Local: Local phlebitis or thrombophlebitis at IV injection site, and swelling or discomfort at IM injection site.
• Other: Superinfections

Interactions

• Aztreonam antagonizes BCG, typhoid, and cholera vaccines when used concurrently.
• Increases the effects of aminoglycosides and penicillin by synergism hence they can be administered in combination.
• Probenecid increases the serum concentration of aztreonam by reducing its elimination
• Aztreonam increases digoxin toxicity.
• It decreases the level of estradiol by reducing the normal intestinal flora.

Nursing Implications

Assessment

History: Assess any allergies to aztreonam, immediate hypersensitivity reaction to penicillin or cephalosporins, renal and hepatic disorders, and lactation

Physical: Assess the skin color, lesions; injection sites; GI mucous membranes, bowel sounds, liver evaluation; GU mucous membranes. Perform culture and sensitivity tests of infected area; LFTs, and renal function tests.

Interventions

• Arrange for culture and sensitivity tests of infected area before therapy.
• For IM administration, reconstitute contents of 15-mL vial with at least 3 mL of diluent per gram of aztreonam. Inject deeply into a large muscle mass. Do not mix with any local anesthetic.
• Discontinue drug and provide supportive measures if hypersensitivity reaction or anaphylaxis occurs.
• Monitor injection sites and provide comfort measures.
• Prepare inhaled form immediately before use. Administer using a nebulizer system; each dose should take 2–3 min. Space doses at least 4 hours apart.
• Administer a bronchodilator before giving inhaled form: If bronchodilator is short acting, give 15 min to 4 hours before each dose; if long-acting, give 30 min to 12 hours before each dose. If patient is on multiple inhaled therapies, use the following order—bronchodilator, mucolytic, aztreonam.
• Provide treatment and comfort measures if superinfections occur.
• Monitor patient’s nutritional status, and provide small, frequent meals and mouth care if GI effects or superinfections interfere with nutrition.

Patient/Family Teaching

• If the patient is using the inhaled form, advise them to the drug at room temperature for up to 28 days.
• Instruct the patient to discard the drug after expiration date.
• Teach the patient how to use the Altera Nebulizer System.
• Instruct the patient to diluted the drug with the saline provided only and it should be used immediately after preparation. Do not mix with other solutions.
• Advise the patient to space their daily treatments at least 4 hours apart. Use this drug for the full 28 days. If you are using other inhaled drugs, take them in the following order—bronchodilators, mucolytics, then this drug.
• Inform the patient that they may experience these side effects such as nausea, vomiting, diarrhea.
• Tell the patient to report pain, soreness at injection site; difficulty breathing; mouth sores; facial swelling

References

• Karch M. (2014). Lippincott’s Nursing Drug Guide. Wolter’s Kluwer/Lippincott Williams and Wilkins. New York, USA.
• Vallerand A., Sanoski C., Deglin J. (2015). Davis’s Drug Guide for Nurses (14^th Ed). F.A Davis Company. Philadelphia, Pennsylvania, USA.
• Whalen K., Finkel R., Panavelil T. (2015). Lippincott Illustrated Reviews Pharmacology (6^th Ed). Wolter’s Kluwer. USA.