ABSTRACT
Gentamicin sulphate is an important drug in the class of aminoglycosides, most commonly used to treat resistant gram-negative organisms. Although highly effective, reservations concerning potential otovestibular toxicity and nephrotoxicity have often limited the use of these agents. Therapeutic drug monitoring has been extensively used to guide dosage adjustments to maximize efficacy and minimize toxicity in aminoglycosides. This was a prospective open study which enrolled patients who were on Gentamicin during the study period of 6 months after taking the informed consent. A base line serum creatinine level was taken before initiating gentamicin. The dose of gentamicin given was based upon the actual body weight of the patient at 3-4mg/kg body wt. After the patient had been “stabilized” with drug, second day after drug administration two blood samples constituting peak and trough were withdrawn. The serum concentrations were checked to see if they were in the therapeutic range (1 microgram/ml to 10 microgram /ml) or not. The patients were also monitored for their creatinine clearance, if the levels were not within the therapeutic range or if there was an undesirable change in creatinine clearance, dosage adjustments were carried out and the process repeated. It was also found that the dosing interval should be lengthened (e.g,. 36, 48 hrs etc) in patients with decreased renal function (creatinine clearance less than 60ml/min). Single daily dosing was comparatively safer and effective than multiple dosing. In conclusion, therapeutic drug monitoring is a useful tool for dosage adjustments in patients with a CLcr < 60ml/min leading to better safety and reduced toxicity.
Key words: Gentamicin sulphate, Aminoglycosides, Resistant gram-negative organisms.