SYSTEMIC ABSORPTION OF NEOMYCIN OCCURS FOLLOWING ORAL ADMINISTRATION
AND TOXIC REACTIONS MAY OCCUR. Patients treated with neomycin
should be under close clinical observation because of the potential
toxicity associated with their use. NEUROTOXICITY (INCLUDING OTOTOXICITY)
AND NEPHROTOXICITY FOLLOWING THE ORAL USE OF NEOMYCIN SULFATE
HAVE BEEN REPORTED, EVEN WHEN USED IN RECOMMENDED DOSES. THE POTENTIAL
FOR NEPHROTOXICITY, PERMANENT BILATERAL AUDITORY OTOTOXICITY AND
SOMETIMES VESTIBULAR TOXICITY IS PRESENT IN PATIENTS WITH NORMAL
RENAL FUNCTION WHEN TREATED WITH HIGHER DOSES OF NEOMYCIN AND/OR
FOR LONGER PERIODS THAN RECOMMENDED. Serial, vestibular and audiometric
tests, as well as tests of renal function, should be performed
(especially in highrisk patients). THE RISK OF NEPHROTOXICITY
AND OTOTOXICITY IS GREATER IN PATIENTS WITH IMPAIRED RENAL FUNCTION.
Ototoxicity is often delayed in onset and patients developing
cochlear damage will not have symptoms during therapy to warn
them of developing eighth nerve destruction and total or partial
deafness may occur long after neomycin has been discontinued.
Neuromuscular blockage and respiratory paralysis have been reported
following the oral use of neomycin. The possibility of the occurrence
of neuromuscular blockage and respiratory paralysis should be
considered if neomycin is administered, especially to patients
receiving anesthetics, neuromuscular blocking agents such as tubocurarine,
succinylcholine, decamethonium, or in patients receiving massive
transfusions of citrate anticoagulated blood. If blockage occurs,
calcium salts may reverse these phenomena but mechanical respiratory
assistance may be necessary.
Concurrent and/or sequential systemic, oral or topical use of
other aminoglycosides, including paromomycin and other potentially
nephrotoxic and/or neurotoxic drugs such as bacitracin, cisplatin,
vancomycin, amphotericin B, polymyxin B, colistin and viomycin,
should be avoided because the toxicity may be additive.
Other factors which increase the risk of toxicity are advanced
age and dehydration.
The concurrent use of neomycin with potent diuretics such as
ethacrynic acid or furosemide should be avoided, since certain
diuretics by themselves may cause ototoxicity. In addition, when
administered intravenously, diuretics may enhance neomycin toxicity
by altering the antibiotic concentration in serum and tissue.