Amikacin

INTRODUCTION

Indications

IM, IV: Treatment of serious infections for which treatment with less toxic anti-infectives is contraindicated or known to be ineffective. Unlabeled Use: Part of combination treatment of Mycobacterium avium complex infections. Intrathecal: With parenteral amikacin in the management of CNS infections. Inhaln: By aerosol nebulization for the prevention of serious pneumonia in high-risk populations.

Action

Inhibits protein synthesis in bacteria at the level of the 30S ribosome. Resists the action of enzymes known to inactivate other aminoglycosides. Therapeutic Effects: Bactericidal action against susceptible bacteria. Spectrum: Notable for activity against Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Proteus, Providencia, Enterobacter, Citrobacter freundii, Serratia, Acinetobacter, Mycobacterium. Amikacin is also active against staphylococci (including methicillin-resistant strains). Acts synergistically with beta-lactam anti-infectives against gram-negative organisms. In the treatment of enterococcal infections, synergy with a penicillin is required.

Adverse Reactions/Side Effects

CNS: vertigo. EENT: ototoxicity (vestibular and cochlear). GU: nephrotoxicity. Neuro: enhanced neuromuscular blockade. Resp: apnea. Misc: hypersensitivity reactions.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Assess respiration and notify physician immediately if patient exhibits any interruption in respiratory rate (apnea) or other signs of respiratory failure (rapid labored breathing, cyanosis, confusion, irritability, sleepiness, headache, oxygen desaturation).

• Monitor signs of hypersensitivity reactions, including pulmonary symptoms (tightness in the throat and chest, wheezing, cough dyspnea) or skin reactions (rash, pruritus, urticaria). Notify physician or nursing staff immediately if these reactions occur.

• Assess any residual muscle weakness that might occur following surgery, especially when neuromuscular junction (NMJ) blockers were used during general anesthesia (this drug enhances the effects of NMJ blockers). Report prolonged muscle weakness to the physician.

• Monitor signs of ototoxicity (hearing loss, tinnitus, dizziness). Report these signs to the physician, and caution the patient and family/caregivers to guard against falls and trauma.

Interventions

• Always wash hands thoroughly and disinfect equipment (whirlpools, electrotherapeutic devices, treatment tables, and so forth) to help prevent the spread of infection. Use universal precautions or isolation procedures as indicated for specific patients.

Patient/Client-Related Instruction

• Advise patient to report signs of nephrotoxicity, including blood or pus in urine, decreased urine output, fatigue, and weight gain from fluid retention.

Pharmacokinetics

Absorption: Poorly absorbed from the GI tract. Well absorbed after IM administration; IV administration results in complete bioavailability.

Distribution: Widely distributed throughout extracellular fluid. Crosses the placenta; small amounts enter breast milk. Poor penetration into CSF (increased when meninges inflamed).

Metabolism and Excretion: Excretion is mainly (>90%) renal; minimal amounts are metabolized by the liver.

Half-life: Infants >7 days: 4–5 hr; Children: ...