Gentamicin is an amino glycoside antibiotic used to treat infections caused by many different types of bacteria.

The bactericidal ability of aminoglycosides has not been fully explained. It is known that the drug attaches to a bacterial cell wall and is drawn into the cell via channels made up of the protein, porin. Once inside the cell, the amino glycoside attaches to the cell's ribosomes. Ribosomes are the intracellular structures responsible for manufacturing proteins. This attachment either shuts down protein production or causes the cell to produce abnormal, ineffective proteins. The bacterial cell cannot survive with this impediment.
Aminoglycosides are absorbed very poorly from the gastrointestinal tract; in fact, aminoglycosides taken orally are excreted virtually unchanged and undiminished in quantity. The typical routes of administration are by intramuscular (injection into a muscle) or intravenous injection (injection into a vein), irrigation, topical skin application, or inhalation. If the infection being treated involves the central nervous system, the drug can be injected into the spinal canal.

INDICATIONS
IM/IV
Serious Infections caused by sensitive organisms. Bacterial neonatal
sepsis, meningitis, endocarditis, UTI, RTI and GI tract infections including
peritonitis, skin, soft tissue, bone and joint infections, burns, septicemia,
biliary infections, ENT infections.

DOSAGE & ADMINISTRATION

Adults: 1mg/kg  8 hourly IM.In serious life threatening infections 1.7 mg/kg 6 or 8 hourly.
Premature babies and neonates : during 1st week:2.5 mg/kg 12 hourly                                 Neonates over 1 week to infant are 6 months : 2.5 mg/kg 8 hourly.
Children 6 months-10 years : 2-2.5 mg/kg 8 hourly.                                                                  Children over 10 years  1.5 mg/kg 8 hourly.                                                                                                   

Note: Renal impairment: Increase the interval between doses keeping  serum creatinine levels as a guide. In patients on dialysis an 8-hour dialysis reduces serum levels of gentamicin by 50%. At the end of each session give 1-1.7 mg/kg for adults and 2 mg/kg for children. For IV use, each dose
of gentamicin diluted with 50-100 ml of IV fluids should be given over 20 mins. Duration 7-10 days.

CONTRAINDICATIONS
History of Hypersensitivity or serious toxic reactions to amino glycosides,
renal impairment, liver disease, hypotension.