Texas Physician Ebook Continuing Education

Antibiotics Review _ __________________________________________________________________________

THE AMINOGLYCOSIDES

Agent

Adult Dosing Range

Pediatric Dosing Range

Route

Common Side Effects

Comments

Amikacin 5 mg/kg every 8 hrs or 7.5 mg/kg every 12 hrs Gentamicin 3–5 mg/kg/day in divided doses every 8 to 12 hrs, or 5–7 mg/kg once daily Neomycin 4–12 g/day in 4 to 6 divided doses for 5 to 6 days, or 4 g/ day for an indefinite period

15–22.5 mg/kg/day every 8 hrs OR 15–20 mg/kg/dose every 24 hours Infants: 2–2.5 mg/ kg/dose every 6 to 8 hrs 50–100 mg/kg/day in 3 to 4 divided doses

IV, IM Renal failure,

Predisposition to auditory/vestibular nerve damage may be genetic; check family history. Check serum levels. Doses are based on lean body mass; maintenance dose is based on calculation with creatinine clearance. Additional dose adjustments are needed in renal failure. Used as a bowel prep for surgery. Is also formulated in some topical eye, ear, and skin preparations. Boxed warning: Risk factors for nephrotoxicity include pre-existing renal impairment, elderly patients, concomitant. May cause ototoxicity; symptoms may be irreversible and may not become evident until after therapy is complete. This is the most ototoxic of aminoglycosides; levels must be monitored closely. Can cause neuromuscular blockade and respiratory paralysis, especially when given soon after muscle relaxants or anesthesia. Effects of nondepolarizing muscle relaxants can be increased. Total body weight (as opposed to ideal body weight) should be used for underweight patients.

vestibular nerve damage, auditory nerve damage

IV, IM, topical

PO, topical

Systemic absorption is possible, resulting in the same side effects as amikacin.

Plazomicin 15 mg/kg once daily for 4-7 days

N/A

IV

Renal failure

Streptomycin 15–30 mg/kg/day or 1–2 g daily

20–40 mg/kg/day every 6 to 12 hrs in divided doses Max: 1 g/dose or 2 g/day

IM Renal failure,

vestibular nerve damage, auditory nerve damage

Tobramycin 1–2.5 mg/kg every 8 to 12 hrs. or 4–7 mg/kg once daily dose

<5 yrs: 2.5 mg/kg every 8 hrs >5 yrs: 2–2.5 mg/kg every 8 hrs

IV, IM inhalation solution, ophthal- mic oint-

Renal failure, vestibular nerve damage, auditory nerve damage

ment or solution

Prescribing information is given for comparison purposes only. The higher dosage ranges reflect dosages for more severe infections. Please consult the manufacturer’s package insert for the antibiotic for complete prescribing information, maximum dosages, and indications. Source: [6; 16] Table 4

cin reduced the subsequent incidence of ventilator-associated pneumonia [174]. Neomycin is often used orally as part of a pre-operative bowel decontamination protocol. The aminoglycosides are widely distributed in extracellular fluid, including pleural fluid, synovial fluid, abscesses, and peritoneal fluid. They are relatively insoluble in lipid, so the volume of distribution is lower in obese patients. They have poor distribution in bile, aqueous humor, bronchial secretions, sputum, and the CSF [15].

Aminoglycosides are excreted unchanged by the kidneys [6]. There is no reduction of dosage necessary in liver failure, as there is no hepatic metabolism of these agents. In renal failure, the dosage must be carefully adjusted based on glomerular filtration rate and measured serum levels. Serum levels should be monitored in all patients with reduced renal function [83].

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MDTX2026

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