Tobramycin Sulphate

Indications

Tobramycin Sulphate is used for: Cystic fibrosis

Adult Dose

Inhalation Cystic fibrosis Indicated for management Pseudomonas aeruginosa in patients with cystic fibrosis Adult: One single-use ampoule (300 mg) 12 hrly, inhaled from a suitable nebuliser for 28 days, then stop for 28 days and repeat in cycles of 28 days as needed.

Child Dose

Inhalation Cystic fibrosis Indicated for management Pseudomonas aeruginosa in patients with cystic fibrosis Child: >6 yr : 300 mg 12 hrly, inhaled from a suitable nebuliser for 28 days, then stop for 28 days and repeat in cycles of 28 days as needed.

Renal Dose

Renal impairment: Dosage adjustment needed.

Administration

Contra Indications

Hypersensitivity to aminoglycosides; pregnancy.

Precautions

Preexisting renal and auditory or vestibular impairment; dehydration; neuromuscular blockade, muscular disorders (e.g. myasthenia gravis, parkinsonism); neonates; elderly; lactation. Lactation: Unknown whether inhaled tobramycin will reach sufficient concentration to be distributed in breast milk; because of the potential for ototoxicity and nephrotoxicity in infants, a decision should be made whether to terminate breastfeeding or discontinue inhaled tobramycin

Pregnancy-Lactation

Pregnancy Aminoglycosides can cause fetal harm; aminoglycosides cross the placenta; published literature reports that use of streptomycin, an aminoglycoside, can cause total, irreversible, bilateral congenital deafness when administered to a pregnant woman; although there are no available data on ophthalmic use of tobramycin in pregnant women to inform a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes, systemic absorption of tobramycin following inhaled administration is expected to be minimal There are risks to mother associated with cystic fibrosis in pregnancy; in animal reproduction studies with subcutaneous administration of tobramycin in pregnant rats and rabbits during organogenesis there were no adverse developmental outcomes; however, ototoxicity was not evaluated in the offspring from these studies; advise pregnant women of potential risk to a fetus Cystic fibrosis may increase risk for preterm delivery Lactation There are no data on presence of drug in either human or animal milk, the effects on breastfed infant, or effects on milk production; limited published data on other formulations of tobramycin in lactating women indicate that tobramycin is present in human milk; however, systemic absorption of tobramycin following inhaled administration is expected to be minimal; therapy may cause alteration in intestinal flora of breastfeeding infant; the developmental and health benefits of breastfeeding should be considered along with mother's clinical need for therapy and any potential adverse effects on breastfed infant from drug or from underlying maternal condition Therapy may cause intestinal flora alteration; advise a woman to monitor breastfed infant for loose or bloody stools and candidiasis (thrush, diaper rash)

Interactions

Increased nephrotoxicity or ototoxicity with etacrynic acid, furosemide, other aminoglycosides, cefalotin, cisplatin, vancomycin, piperacillin, ciclosporin, amphotericin B. Decrease serum tobramycin levels with miconazole. Potentially Fatal: Increased neuromuscular-blocking activity with magnesium and other neuromuscular-blocking agents.

Adverse Effects

Side effects of Tobramycin Sulphate : >10% Voice alteration (12.8%) 1-10% Myalgia (4.7%), Laryngitis (4.3%), Tinnitus (3%), Epistaxis (3%)

Mechanism of Action

Tobramycin acts by binding to 30S ribosomal subunits thus interfering with bacterial protein synthesis. It is active against many aerobic gram-negative bacteria and some aerobic gram-positive bacteria but inactive against Chlamydia, fungi, viruses, and most anaerobic bacteria.