Aminoglycosides

All aminoglycosides are produced by soil actinomycetes. All are bactericidal and more active at alkaline pH.

Mechanism of Action

The amoniglycosides are bactericidal antibiotics all having same properties.

• Transport of the aminoglycosides through the bacterial cell wall and cytoplasmic membrane
• Binding to ribosome resulting in inhibition of protein synthesis.
• The cidal action is based on secondary changes in the integrity of bacterial cell membrane .

Precautions and Interactions

• Avoid during pregnancy.
• Avoid concurrent use of other ototoxic, nephrotoxic drugs.
• Cautious use in patients past middle age and those with kidney damage.
• Cautious use of muscle relaxants in patients receiving aminoglycosides.
• Do not mix any other drug with aminoglycoside in the same syringe.

Shared toxicities

• Ototoxicity.
• Nephrotoxicity.
• Neuromuscular blockade.

Generic name: Streptomycin

Commercial name: S 0.75gm, 1gm vial.

Indication

• Tuberculosis.
• Sub-acute bacterial endocarditis.
• Plague.
• Tulareamia.

Warnings/Precautions and Contraindication

• Topical use is contraindicated for fear of contact sensitization.

Adverse effects

• Rashes, eosinophilia, fever and exfoliative dermatitis are noticed.
• Hypersensitivity is rare.
• Pain at injection site.
• Paraesthsia and scotoma are occasional.

Generic name: Gentamicin

Commercial name: Garamycin, Gentasporin, Genticyn 20,60, 80, 240 mg/vial inj; also 0.3% eye/ ear drops, 0.1 % skin cream.

Indication

• Preventing and treating respiratory infections in critically ill patients, in those with impaired host defence.
• Pseudomonas, Proteus or Klebsiella infections in critically ill patients.
• Meningitis caused by gram-ve bacilli.
• Dosage: For average adult with normal renal clearance 3-5mg/kg/day I.M. either single dose or divided in 3 or 8 hourly doses.

Warnings/Precautions and Contraindication

• Risk of toxicity is greater with impaired renal function, high dosage or prolonged therapy.
• Avoid concurrent and/or sequential topical and /or systematic use of other potential neurotoxic and/or nephrotoxic drugs.
• W/P: Nueromuscular blockade, respiratory paralysis, ototoxicity and nephrotoxicity may occur.

Generic name: Tobramycin

Commercial name: Tobacin 20, 60, 80mg in 2ml inj; 0.3% eye drops, Tobraneg  20, 40, 80mg per 2ml vial inj.

Indication

• Serious infections caused by Pseudomonas and Proteus.

Warnings/precautions and Contraindication

• Caution with muscular disorders and renal, auditory, vestibular or neuromuscular disorders.

Adverse effects

• Voice alteration, taste perversion and tinnitus.