Anti-Infectives

Commonly Prescribed Drugs

See Mechanism of Action of Select Anti-infectives table.

Pharmacologic Profile

General Use

Treatment and prophylaxis of various bacterial infections. See specific drugs for spectrum and indications. Some infections may require additional surgical intervention and supportive therapy.

General Action and Information

MECHANISM OF ACTION OF SELECT ANTI-INFECTIVES

DRUG CLASS	DRUG(S)	MECHANISM
Aminoglycosides	Amikacin, gentamicin, neomycin, streptomycin, and tobramycin	Inhibit protein synthesis by binding to 30S ribosomal subunit
Beta-lactams
β-lactamase inhibitor	Sulbactam/durlobactam	Inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins
Carbapenems	Ertapenem, imipenem/cilastatin, and meropenem
Cephalosporins	1st generation: Cefadroxil, cefazolin, and cephalexin 2nd generation: Cefaclor, cefotetan, cefoxitin, cefprozil, and cefuroxime 3rd generation: Cefdinir, cefixime, cefotaxime, cefpodoxime, ceftazidime, and ceftriaxone 4th generation: Cefepime 5th generation: Ceftaroline and ceftobiprole
Monobactam	Aztreonam and aztreonam/avibactam
Penem	Sulopenem etzadroxil/probenecid
Penicillins	Amoxicillin, ampicillin, penicillin G, and penicillin V
Penicillins, Penicillinase-Resistant	Dicloxacillin, nafcillin, and oxacillin
Cyclic lipopeptide	Daptomycin	Causes rapid depolarization of cell membrane → inhibits protein, DNA, and RNA synthesis
Fluoroquinolones	Ciprofloxacin, delafloxacin, levofloxacin, moxifloxacin, and ofloxacin	Inhibit DNA gyrase and topoisomerase IV → inhibit DNA synthesis
Glycopeptides	Dalbavancin, oritavancin, telavancin, and vancomycin	Inhibits bacterial cell wall synthesis by blocking glycopeptide polymerization
Glycylcycline	Tigecycline	Inhibit protein synthesis by binding to 30S ribosomal subunit
Lincosamide	Clindamycin	Inhibits protein synthesis by binding to 50S ribosomal subunit
Macrolides	Azithromycin, erythromycin, and fidaxomicin	Inhibit protein synthesis by binding to 50S ribosomal subunit
Nitroimidazole	Metronidazole and secnidazole	Cause DNA strand breakage
Oxazolidinone	Linezolid and tedizolid	Inhibits protein synthesis by binding to the 23S ribosome of the 50S subunit
Tetracyclines	Doxycycline	Inhibit protein synthesis by binding to 30S ribosomal subunit
Triazaacenaphthylene	Gepotidacin	Inhibits DNA gyrase and topoisomerase IV → inhibits DNA synthesis

Contraindications

Known hypersensitivity to individual agents. Cross-sensitivity among related agents may occur.

Precautions

Culture and susceptibility testing are desirable to optimize therapy. Dosage modification may be required in patients with hepatic or renal impairment. Use cautiously in pregnant and lactating women. Prolonged inappropriate use of broad spectrum anti-infective agents may lead to superinfection with fungi or resistant bacteria.

Interactions

Penicillins and aminoglycosides chemically inactivate each other and should not be physically admixed. Erythromycin may ↓ hepatic metabolism of other drugs. Probenecid ↑ serum levels of penicillins and related compounds. Fluoroquinolone and tetracycline absorption may be ↓ by antacids, bismuth subsalicylate, calcium, iron salts, sucralfate, and zinc salts.

Nursing Implications

Assessment

Assess patient for signs and symptoms of infection prior to and throughout therapy.
Determine previous hypersensitivities in patients receiving penicillins or cephalosporins.
Obtain specimens for culture and sensitivity prior to initiating therapy. First dose may be given before receiving results.
Monitor bowel function. Diarrhea, abdominal cramping, fever, and bloody stools should be reported to health care provider promptly as a sign of Clostridioides difficile-associated diarrhea.

Implementation

Most anti-infectives should be administered around the clock to maintain therapeutic serum drug levels.

Patient/Family Teaching

Instruct patient to continue taking medication around the clock until finished completely, even if feeling better.
Advise patient to report the signs of superinfection (black, furry overgrowth on the tongue; vaginal itching or discharge; loose or foul-smelling stools) and allergy to health care provider.
Instruct patient to notify health care provider if fever and diarrhea develop, especially if stool contains pus, blood, or mucus. Advise patient not to treat diarrhea without consulting health care provider.
Instruct patient to notify health care provider if symptoms do not improve.

Evaluation/Desired Outcomes