Page 421 - Feline Cardiology

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

Dexmedetomidine Alpha-2 agonist 40 mcg/kg IM General sedation, notably in cats with 0.5 mg/ml
(Dexdomitor [V]) sedative and hypertrophic cardiomyopathy. Onset of (= 500 mcg/ml)
analgesic sedation 5–15 minutes after injection; peak at Inj
30 minutes; sedation dissipated by 3 hours VM
after injection. Reflex bradycardia is a response
to vasoconstriction and need not be treated,
even with heart rates <70 beats/minute (18%
of cats); if concern, blood pressure can be
measured and normal to elevated levels are
expected. Indication in HCM is based on
arterial vasoconstriction, decreasing heart rate,
which improves diastolic filling and reduces
myocardial oxygen consumption.
Contraindicated in systemic hypertension. Rare
cases of postadministration pulmonary edema;
monitor respiratory character and rate. Greater
potency than medetomidine equates to a lower
dosage for similar sedation. Vomiting may
occur within minutes after administration; cats
should be fasted prior to dosing. Reversal
agent: atipamezole (Antisedan) in equal
volumes to dexmedetomidine dose.

Diazepam (Valium Benzodiazepine 0.1–0.5 mg/kg Almost always used in conjunction with other 1, 10 mg/ml
[H]) sedative IV agents, notably butorphanol (for moderate Inj
sedation) or either dexmedetomidine or HM
ketamine (for heavy sedation). Safe; very
minimal cardiovascular effect. Provides mild
additional sedation, no practical effect if given
as sole drug. Main disadvantage over
midazolam is no IM route.
Digoxin (Lanoxin Cardiac glycoside 0.01875– Indicated for dilated cardiomyopathy causing 0.125mg
[H]) 0.03125 mg/cat congestive heart failure. Possible indications in T
PO q 48h (= restrictive/unclassified cardiomyopathy, dilated HM
1/8–1/4 of cardiomyopathy prior to congestive heart Caution:
0.125 mg failure. Contraindicated in hypertrophic 0.25 mg
tablet) cardiomyopathy. Home monitoring for signs of tabs also
digoxin toxicosis (warranting immediate available
discontinuation) is essential: vomiting, (avoid due to risk
inappetence, lethargy, and/or diarrhea. Target of double-dosing)
serum levels (now 0.5–1 ng/ml; previously Elixir (0.05 mg/
1–2 ng/ml) not correlated to any benefit in cats, ml)
merely extrapolated from human medicine; usually
effects on increasing vagal tone seen at lower disliked by
doses. Lower dosage warranted when cats
concurrent treatment with furosemide, aspirin,
and low sodium diet. IV form not recommended
Drug Formulary (greater risk of toxicosis, and benefits of digoxin
are chronic rather than acute). Adjunctive
therapy as mild negative chronotrope for
supraventricular tachyarrhythmias.

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