Study Notes on Aminoglycosides

Aminoglycosides: A class of antibiotics used primarily to treat severe systemic infections caused by aerobic, Gram-negative bacteria.
- Examples of target bacteria:
- Escherichia coli
- Klebsiella pneumoniae
- Pseudomonas aeruginosa
- Enterobacter species

Aminoglycosides work by binding to the 30S subunit of the bacterial ribosome.
- Effect: Disruption of bacterial protein synthesis, leading to bacterial cell death.
- To improve efficacy, they may be used together with cell wall inhibitors (e.g., penicillins or cephalosporins) to enhance entry into bacterial cells.

Absorption: Poorly absorbed in the gastrointestinal tract.
Routes of administration:
- Primarily intramuscularly or intravenously.
- Topical application for gentamicin and tobramycin for treats eye or ear infections.
- Nebulized tobramycin for Pseudomonas infections in cystic fibrosis patients.
- Oral neomycin for treating hepatic encephalopathy and pre-colorectal surgery infection reduction.

Streptomycin and Amikacin: Effective for treating mycobacterial infections.
Gentamicin: Used topically for eye/ear infections.
Tobramycin: Nebulized for lung infections associated with cystic fibrosis.
Neomycin: Used orally to treat liver condition and infection prevention before colorectal surgeries.

Post-Antibiotic Effect: Persistent bactericidal activity even after cessation of medication.
Toxicity Risks:
- Neurotoxicity: Risk of hearing loss, vertigo, ataxia, and loss of balance.
- Nephrotoxicity: Potential progression to kidney failure.
- Gastrointestinal side effects: Such as anorexia, nausea, vomiting, and diarrhea.
- Bone marrow suppression: Increased infection risk.
- Neuromuscular blockade: Can inhibit acetylcholine release, causing weakness and paralysis, especially with anesthetics or neuromuscular blockers (e.g., succinylcholine).

Contraindicated in patients:
- With renal or hepatic disease.
- With pre-existing hearing loss.
- With active infections affected by aminoglycoside activity on normal defenses.
- Specific caution required for patients with myasthenia gravis or parkinsonism due to risk of exacerbation from neuromuscular blockade.
- Use during pregnancy should be avoided, with caution during breastfeeding and in neonates.
Use cautiously in elderly patients or those taking loop diuretics/neurotoxic or nephrotoxic medications.

Patient History: Check for hearing difficulties or balance issues.
Baseline Assessment:
- Measure weight, vital signs, and hydration status.
- Review medication history for potential interactions leading to neurotoxicity/nephrotoxicity.
Laboratory Tests: Assess CBC, renal and liver function tests, culture and sensitivity results, and urinalysis.
Pregnancy Test: Required for female patients of childbearing age to confirm negative status.

Confirm and calculate dosing in mg/kg/day to ensure appropriate administration.
Patient Communication: Explain medication purpose and administration process, emphasizing the importance of monitoring for side effects.

Ensure patient hydration through prescribed fluids (oral or IV) before aminoglycoside administration.
Infuse gentamicin over 30 minutes to 1 hour.

Vital Signs: Regular monitoring of vital signs during administration.
Neurotoxicity Signs: Instruct patient to report symptoms like tinnitus, dizziness, vertigo, or headaches.
Nephrotoxicity Monitoring:
- Closely monitor fluid intake/output and renal function tests.
- Evaluate urinalysis for protein, casts, red blood cells, and specific gravity.
Trough Level: Draw trough level 1 hour before the next dose, hold if it exceeds 2 mcg/mL.
Infection Signs: Regular checks for opportunistic infection indicators (e.g., fever, stomatitis).
- If bloody diarrhea arises, send a specimen to test for Clostridioides and inform healthcare provider.

Continuously monitor medication trough levels following protocol.
Watch for side effects and evaluate therapeutic response (e.g., absence of fever, infection resolution).

Aminoglycosides: Antibiotics for severe infections that act by binding to ribosomal subunits to kill bacteria.
Risks: Notable for neurotoxicity, nephrotoxicity, and neuromuscular blockade risks.
Nursing Implications: Include thorough assessments, toxicity monitoring, and patient education regarding treatment expectations and symptom recognition.