Neurotoxicity (manifested as both auditory and vestibular ototoxicity) can occur. Other neurotoxicity manifestations include numbness, skin tingling, muscle twitching, and seizures.
Eighth-cranial nerve impairment develops principally in patients with preexisting renal damage and in those with normal renal function who receive doses higher or treatment longer than recommended.
Aminoglycoside-induced ototoxicity is irreversible, usually bilateral, and may be partial or total.
Risk of hearing loss increases with degree of exposure to either high peak or high trough serum concentrations.
Patients developing cochlear damage may not have symptoms during aminoglycoside treatment to warn them of eighth-cranial nerve toxicity and total or partial, irreversible, bilateral deafness may occur after drug discontinued.
Nephrotoxicity
Potentially nephrotoxic.
Aminoglycoside-induced nephrotoxicity usually is reversible.
Nephrotoxicity develops principally in patients with preexisting renal damage and in those with normal renal function who receive doses higher or treatment longer than recommended.
Rarely, nephrotoxicity may become apparent several days after discontinuance.
Patient Monitoring
Patients should be under close clinical observation because of potential ototoxicity and nephrotoxicity.
Closely monitor renal and eighth-cranial nerve function, especially in patients with known or suspected renal impairment at start of treatment and also in those whose renal function is initially normal but who develop renal dysfunction during treatment.
Monitor serum tobramycin concentrations periodically to ensure adequate concentrations and avoid potentially toxic and prolonged peak concentrations (>12 mcg/mL).
Rising trough concentrations (>2 mcg/mL) may indicate tissue accumulation.
Tissue accumulation, excessive peak concentrations, cumulative dose, advanced age, and dehydration may contribute to ototoxicity and nephrotoxicity.
Evaluate urine for decreased specific gravity and increased excretion of protein, cells, and casts; periodically determine BUN, Scr, and Clcr.
When feasible, perform serial audiograms in patients old enough to be tested, particularly high-risk patients.
Discontinue tobramycin or adjust dosage if there is evidence of impaired renal, vestibular, or auditory function.
Use with caution in neonates and premature infants because of their renal immaturity and prolonged tobramycin serum half-life.
Interactions
Avoid concurrent and/or sequential use of other neurotoxic or nephrotoxic drugs, particularly other aminoglycosides, cephaloridine (no longer available in US), viomycin, polymyxin B, colistin, cisplatin, and vancomycin.
Avoid concurrent use of potent diuretics (e.g., ethacrynic acid, furosemide) since diuretics themselves may cause ototoxicity and IV diuretics enhance toxicity by altering serum and tissue aminoglycoside concentrations.
Pregnancy
Aminoglycosides can cause fetal harm when administered to a pregnant woman.
This medicine is for injection into a muscle or infusion into a vein. It is usually given by a health care professional in a hospital or clinic setting. Take all of your medicine as directed even if you think you are better. Do not skip doses or stop your medicine early.
If you get this medicine at home, you will be taught how to prepare and give this medicine. Use exactly as directed. Take your medicine at regular intervals. Do not take your medicine more often than directed.
It is important that you put your used needles and syringes in a special sharps container. Do not put them in a trash can. If you do not have a sharps container, call your pharmacist or healthcare provider to get one.
Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for selected conditions, precautions do apply.
Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.
NOTE: This medicine is only for you. Do not share this medicine with others.
What if I miss a dose?
If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.
What may interact with this medicine?
Do not take this medicine with any of the following medications:
This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.
What should I watch for while using this medicine?
Tell your doctor or health care professional if your symptoms do not improve or if you get new symptoms.
Tell your doctor or health care professional if you have any hearing problems, or problems passing urine.
What side effects may I notice from receiving this medicine?
Side effects that you should report to your doctor or health care professional as soon as possible:
This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Where should I keep my medicine?
Keep out of the reach of children.
If you are using this medicine at home, you will be instructed on how to store this medicine. Throw away any unused medicine after the expiration date on the label.
NOTE:This sheet is a summary. It may not cover all possible information. If you have questions about this medicine, talk to your doctor, pharmacist, or health care provider.
Remember, keep this and all other medicines out of the reach of children,
never share your medicines with others, and use this medication only for the indication prescribed.
