Page 1357 - Problem-Based Feline Medicine

67 – SPECIAL CONSIDERATIONS RELATED TO DRUG USE IN CATS 1349

Adverse effects
METHIMAZOLE, CARBIMAZOLE
Inconsistent sedation.
Clinical action Increased risk of excitation.
Anti-thyroid.
This may reflect differences in the type or concentra-
tion of opioid receptors in cats or a relative overdosage.
Adverse effects
Side effects observed in about 18% of cats treated with Dose
methimazole (or its metabolite, carbimazole) include Meperidine 3–5 mg/kg IM, IV.
anorexia, vomiting, self-induced facial excoriation,
Morphine 0.1 mg/kg SC, IM.
bleeding diathesis and hepatopathy.
Butorphanol 0.4 mg/kg q 6 h SC or
About 4% will develop serious hematological side
0.2 mg/kg q 6 h IV.
effects.
Buprenorphine 0.01 mg/kg SC, IM q 8–12 h.
Although about 20% develop autoantibodies, this does
not appear to be associated with clinical immune-medi-
ated disease.
ORGANOPHOSPHATES

Recommended dose Clinical action
5 mg/cat q 8–12 h induction then 2.5–5 mg/cat q 8–12 Insecticide.
h for maintenance.
Adverse effects
Cats are more sensitive to the effects of organophos-
METRONIDAZOLE phates than dogs although the mechanism for this is
unknown.
Clinical action It is not related to different hepatic metabolizing capac-
Antibiotic. ity as organophosphates are metabolized by
cholinesterases located at nerve endings.
Adverse effects Toxicity may be acute (similar signs to dogs) or chronic
Reversible CNS toxicity has been reported in cats result- or delayed.
ing in disorientation, ataxia, seizures and blindness.
Chronic or delayed toxicity manifests as paresis or
paralysis which may or may not be reversible.
Dose
Toxic epidermal necrolysis has been reported in cats
10–25 mg/kg q 24 h or 10–25 mg/kg q 12 h (for
treated topically with organophosphate based flea
Giardia).
rinses.
A survey of the effects of flea collars in cats revealed a
OPIOIDS high number of adverse reactions ranging from der-
matitis to death.
Some morphine derivatives (excluding meperidine
[pethidine], butorphanol and buprenorphine).
POTASSIUM BROMIDE

Clinical action Clinical action
Analgesia. Anti-convulsant.