PRECAUTIONS
General
Since Coly-Mycin M Parenteral
is eliminated mainly by renal excretion, it should be used with caution when
the possibility of impaired renal function exists. The decline in renal
function with advanced age should be considered.
When actual renal impairment is
present, Coly-Mycin M Parenteral may be used, but the greatest caution should
be exercised and the dosage should be reduced in proportion to the extent of
the impairment. Administration of amounts of Coly-Mycin M Parenteral in excess
of renal excretory capacity will lead to high serum levels and can result in
further impairment of renal function, initiating a cycle which, if not
recognized, can lead to acute renal insufficiency, renal shutdown, and further
concentration of the antibiotic to toxic levels in the body. At this point,
interference of nerve transmission at neuromuscular junctions may occur and
result in muscle weakness and apnea (see OVERDOSAGE section).
Signs indicating the development of impaired renal
function include: diminishing urine output, rising BUN and serum creatinine and
decreased creatinine clearance. Therapy with Coly-Mycin M Parenteral should be
discontinued immediately if signs of impaired renal function occur. However, if
it is necessary to reinstate the drug, dosing should be adjusted accordingly
after drug plasma levels have fallen (see DOSAGE AND ADMINISTRATION section).
Prescribing Coly-Mycin M in the absence of a proven or
strongly suspected bacterial infection or a prophylactic indication is unlikely
to provide benefit to the patient and increases the risk of the development of
drug-resistant bacteria.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Long-term animal carcinogenicity studies and genetic
toxicology studies have not been performed with colistimethate sodium. There
were no adverse effects on fertility or reproduction in rats at doses of 9.3
mg/kg/day (0.30 times the maximum daily human dose when based on mg/m²).
Pregnancy
Teratogenic Effects -Pregnancy Category C
Colistimethate sodium given
intramuscularly during organogenesis to rabbits at 4.15 and 9.3 mg/kg resulted
in talipes varus in 2.6% and 2.9% of fetuses, respectively. These doses are
0.25 and 0.55 times the maximum daily human dose based on mg/m². In
addition, increased resorption occurred at 9.3 mg/kg. Colistimethate sodium was
not teratogenic in rats at 4.15 or 9.3 mg/kg. These doses are 0.13 and 0.30
times the maximum daily human dose based on mg/m². There are no
adequate and well-controlled studies in pregnant women. Since colistimethate
sodium is transferred across the placental barrier in humans, it should be used
during pregnancy only if the potential benefit justifies the potential risk to
the fetus.
Nursing Mothers
It is not known whether colistimethate sodium is excreted
in human breast milk. However, colistin sulphate is excreted in human breast
milk. Therefore, caution should be exercised when colistimethate sodium is
administered to nursing women.
Geriatric Use
Clinical studies of colistemethate sodium did not include
sufficient numbers of subjects aged 65 and over to determine whether they
respond differently from younger subjects. Other reported clinical experience
has not identified differences in responses between the elderly and younger
patients. In general, dose selection for an elderly patient should be cautious,
usually starting at the low end of the dosing range, reflecting the greater
frequency of decreased hepatic, renal, or cardiac function, and of concomitant
disease or other drug therapy. This drug is known to be substantially excreted
by the kidney, and the risk of toxic reactions to this drug may be greater in
patients with impaired renal function. Because elderly patients are more likely
to have decreased renal function, care should be taken in dose selection, and
it may be useful to monitor renal function.
Pediatric Use
In clinical studies, colistimethate sodium was
administered to the pediatric population (neonates, infants, children and
adolescents). Although adverse reactions appear to be similar in the adult and
pediatric populations, subjective symptoms of toxicity may not be reported by
pediatric patients. Close clinical monitoring of pediatric patients is
recommended.