Brand names Cidomycin, Genticin, Minims gentamicin
Used in the following combined preparation Gentisone HC
QUICK REFERENCE
Drug group Aminoglycoside antibiotic
Overdose danger rating Low
Dependence rating Low
Prescription needed Yes
Available as generic Yes
GENERAL INFORMATION
Gentamicin is one of the aminoglycoside antibiotics. The injectable form is usually reserved for hospital treatment of serious infections. These include lung, urinary tract, bone, joint, and wound infections, as well as peritonitis, septicaemia, and meningitis. This form is also used together with a penicillin for prevention and treatment of heart valve infections (endocarditis).
In the form of drops, gentamicin is used to treat eye and ear infections. Gentamicin given by injection can have serious adverse effects on the ears and the kidneys. Damage to the ears may lead to deafness and problems with the balance mechanism in the inner ear. Courses of treatment are, therefore, limited to seven days when this is possible. Treatment is monitored by measuring blood levels of gentamicin, especially when high doses are needed or kidney function is poor.
INFORMATION FOR USERS
Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.
How taken/used Injection, eye/ear drops.
Frequency and timing of doses 1–3 x daily (injection); 3–4 x daily or as directed (ear drops); every 2 hours or as directed (eye drops).
Adult dosage range According to condition and response (injection); according to your doctor’s instructions (eye and ear drops).
Onset of effect Within 1–2 hours.
Duration of action 8–12 hours.
Diet advice None.
Storage Keep in original container at room temperature out of the reach of children.
Missed dose Apply eye/ear preparations as soon as you remember.
Stopping the drug Complete the course. Even if you feel better, the original infection may still be present and may recur if treatment is stopped too soon.
Exceeding the dose Although overdose by injection is dangerous, it is unlikely because treatment is carefully monitored. For other preparations of the drug, an occasional unintentional extra dose is unlikely to cause concern. But if you notice any unusual symptoms, notify your doctor.
POSSIBLE ADVERSE EFFECTS
Adverse effects are rare but those that occur with the injected form of the drug may be serious. Dizziness, vertigo, impaired hearing, and changes in the urine (such as bloody or cloudy urine) should be reported to your doctor promptly and you should stop using the drug. Nausea and vomiting may also occur. If ear drops are used when the eardrum is perforated, damage to the inner ear may occur. Blurred vision or eye irritation may occur with the eye preparations and should be reported to your doctor. Allergic reactions, including rash and itching, may occur with all preparations that contain gentamicin. If such reactions do occur, stop using the drug and contact your doctor immediately.
INTERACTIONS
General note A wide range of drugs, including furosemide, vancomycin, and cephalosporins, increase the risk of hearing loss and/or kidney failure with gentamicin given by injection.
SPECIAL PRECAUTIONS
Be sure to tell your doctor if:
· You have a long-term kidney problem.
· You have a hearing disorder, especially a perforated eardrum.
· You have myasthenia gravis.
· You have Parkinson’s disease.
· You have previously had an allergic reaction to aminoglycosides.
· You are taking other medicines.
Pregnancy No evidence of risk with eye or ear drops. Injections are not prescribed, as they may cause hearing defects in the baby. Discuss with your doctor.
Breast-feeding No evidence of risk with eye or ear preparations. Given by injection, the drug may pass into the breast milk. Discuss with your doctor.
Infants and children Reduced dose necessary for injections.
Over 60 Increased likelihood of adverse effects. Close monitoring of treatment is therefore necessary.
Driving and hazardous work No known problems from preparations for the eye or ear.
Alcohol No known problems.
PROLONGED USE
Not usually given for longer than seven days. When given by injection, there is a risk of adverse effects on hearing and balance.
Monitoring Blood levels of the drug are usually checked if it is given by injection. Tests on kidney function are also usually carried out.