Aminoglycosides are antibiotics (they exert their effects against bacteria).
The term aminoglycoside is derived from its structure; two amino sugars linked to a central hexose nucleus by a glycoside.
Drugs in this antibiotics class include:
• Amikacin
• Gentamycin
• Neomycin
• Streptomycin
• Tobramycin
• Kanamycin
• Paromomycin
• Plazomicin
Pregnancy Category: D
It can be used in life threatening conditions when there is no safer drug. Studies have shown potential risks to fetal life with its use.
Mechanism of Action
They are bactericidal. In susceptible organisms, they inhibit protein synthesis by binding to the 30S ribosomal sub-unit. They inhibit protein synthesis in two ways;
• They interfere with the assembly of the key ribosome
• Cause the 30S sub-unit of a completed ribosome to misinterpret the genetic code
Indications
• Short term treatment of infections caused by susceptible strains like Klebsiella species, Pseudomonas species, Escherichia coli, Proteus species, Providencia species, Serratia species and Acinetobacter species
• Used in combination with a penicillin in neonatal sepsis when other antibiotics are contraindicated
• Since oral aminoglycosides are poorly absorbed, they can be used to suppress GI bacterial flora
• Initial treatment of infections due to staphylococci where penicillins are contraindicated
Cautions and Contraindications
• Use cautiously in patients with: diminished hearing, impaired renal function, neuromuscular disorders; dehydrated patients, and elderly patients.
• Contraindicated in patients with hypersensitivity to aminoglycosides, hepatic disease, renal disease, preexisting hearing loss, myasthenia gravis, parkinsonism, lactation and infant botulism and pregnancy. (Pregnancy category D).
Adverse Effects
• Nervous System: Ototoxicity, headaches, tremors, neuromuscular blockade, paresthesia, visual disturbances, numbness
• Cardiovascular system: Hypertension, hypotension, palpitations
• Gastrointestinal system: Nausea, vomiting, diarrhea, anorexia, hypersalivation, splenomegaly
• Hematological: Hemolytic anemia, electrolyte disturbances, thrombocytopenia, leukopenia, leukocytosis, eosinophilia, pancytopenia
• Vital organs (Kidney and Liver): Nephrotoxicity, hepatomegaly, hepatic toxicity
• Hypersensitivity: Itching, rash, urticaria, purpura and exfoliative dermatitis
• Irritation, pain and superinfections at the intramuscular injected sites
Interaction
• When used concurrently with cephalosporins and potent diuretics, there is increased ototoxic and nephrotoxic effects
• Neuromuscular junction blockers and anesthesia increases the chances of neuromuscular blockade, especially when aminoglycosides are administered shortly after these drugs have been administered.
Nursing Considerations
Assessment
• Assess the patient for signs and symptoms of infection before initiating therapy. The assessment should continue throughout the course of the therapy
• Assess for any allergic reaction to aminoglycosides
• Assess for conditions like preexisting hearing loss, myasthenia gravis, hepatic and renal diseases, dehydration and neuromuscular disorders
• Obtain specimens for culture and sensitivity, kidney tests and liver function tests
Interventions
• Monitor the patient for ototoxicity and nephrotoxicity
• Discontinue therapy if there are no clinical improvement by the third to fifth day. The usual duration of the regimen is 7-10 days
• Monitor auditory and kidney functions daily if the drug is used for more than 10 days
• Monitor drugs levels if the drug is used for prolonged periods
• Give a deep intramuscular injection to prevent abscess
• Ensure the patient is adequately hydrated before and during the therapy
• If the patient is nauseated, vomiting or experiencing anorexia, administer small frequent meals
Patient/Family Teaching
• Instruct the patient to complete the regimen as prescribed even if they are feeling better
• Teach the patient about the side effects of the drugs
• Advise the patient to report pain, dizziness, hearing loss, changes in urine pattern, breathing difficulty or rash
• Instruct the patient to notify the healthcare provider if symptoms do not improve
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 (14th Ed). F.A Davis Company. Philadelphia, Pennsylvania, USA.
Whalen K., Finkel R., Panavelil T. (2015). Lippincott Illustrated Reviews Pharmacology (6th Ed). Wolter’s Kluwer. USA.
