Page 430 - Feline Cardiology

Generic Name Indications/Drug Dosage and Comments Available sizes
(Brand Name) Type Possible Routes
of Admin.

Metoprolol Beta-1 specific 2–15 mg/cat Poorly studied in cats, likely because of 25, 50 mg Tab
(Lopressor [H]) adrenergic blocker PO q 8h inconvenience of tablet splitting (smallest 25, 50,
tablet size is 25 mg). As with all beta blockers, 100 mg
start at low dose and uptitrate to desired SR
effect. Same general characteristics as atenolol Tab
(which generally supersedes metoprolol in the All HM
cat). Metoprolol tartrate is regular
formulation; metoprolol succinate is sustained
release (but pharmacokinetics of release/
absorption/metabolism are unknown in the
cat).
Mexiletine Class Ib anti- 3 mg/kg A safe dosage has not been established for 150, 200,
(Mexitil [H]) arrhythmic PO q 8–12 h the cat; similar drug class as lidocaine; 250 mg
therefore indication is PVCs/VT, and risks of Cap, Tab
adverse effects (ataxia, seizures; or HM
bradycardia, collapse) are more likely in this
species than in the dog at the standard
canine dosage of 4–8 mg/kg PO q 8–12h.
May be considered in cats that have severe
myocardial failure that cannot tolerate a beta
blocker for treatment of severe ventricular
arrhythmias, or in combination with a beta
blocker or sotalol in refractory ventricular
arrhythmias. Increasingly difficult to obtain
due to decreased demand in human
cardiology.
Midazolam Benzodiazepine 0.1–0.5 mg/kg Almost always used in conjunction with other 1, 10 mg/ml
(Versed [H]) sedative IM or IV agents, notably an opioid (for moderate Inj
sedation) or either medetomidine or ketamine HM
(for heavy sedation). Safe; very minimal
cardiovascular effect. Provides mild additional
sedation, no practical effect if given as sole
drug. Previously expensive, now inexpensive
as generic. Main advantage over diazepam is
equal efficacy as IM or IV injection.
Minipress—see
Prazocin
Continued

455 Drug Formulary