Page 429 - Feline Cardiology

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

Lovenox—see
Heparin, low
molecular weight
Magnesium Mineral 75–100 mg/ Ventricular antiarrhythmic. 50% of dose can 200 mg/ml
chloride kg/24h be given in 2–4 hours if necessary (e.g., (=1.97 mEq/ml)
IV documented hypomagnesemia and rapid/ Inj
(100 mg = symptomatic ventricular tachycardia). Do not
2+
1 mEq Mg ) exceed 200 mg/kg daily. Unsubstantiated in the
cat; rarely used (preference for magnesium sulfate).
Magnesium Mineral 1–2 mEq/kg/d Supplementation for chronic hypomagnesemia Many
hydroxide PO (29 mg (e.g., induced by diuretics). Excess dose may HM
magnesium be laxative; monitor for diarrhea and adjust OTC
hydroxide = dosage accordingly. Common formulation of
2+
1 mEq Mg ) magnesium hydroxide is Milk of Magnesia,
2+
which contains 2.4–2.9 mEq (70–84 mg) mg
per gram, or approximately 13.66 mEq
2+
(396 mg) Mg per 5 ml teaspoon.
Magnesium Mineral 30 mg/kg Ventricular antiarrhythmic.* Treatment of 100, 125,
sulfate slow IV choice when ventricular tachycardia coexists 500 mg/ml
(125 mg = with hypomagnesemia. Option for treatment (0.8, 1,
2+
1 mEq Mg ) of any refractory symptomatic ventricular 4 mEq/l,
arrhythmia. Hypomagnesemia may occur respectively)
concurrently with hypokalemia (either Inj
spontaneously or due to drug effects, e.g., HM
diuretics) but cats with HCM do not have
lower serum Mg levels than control cats.
*Considered 3rd line treatment for cardiac
arrest, after epinephrine/electrical
defibrillation, lidocaine/vasopressin.

Medetomidine Alpha-2 agonist 40–80 mcg/kg General sedation, notably used in cats with 1 mg/ml (=
(Domitor [V]) sedative and IM; dosage of hypertrophic cardiomyopathy. Onset of 1000 mcg/ml)
analgesic 10–40 mcg/kg sedation 5–15 min. after injection; peak at 30 Inj
is often minutes; sedation dissipated by 3 hours VM
adequate for postinjection. Reflex bradycardia is a response
echo (10–20 to vasoconstriction and need not be treated; if
minutes), concern, blood pressure can be measured and
especially if IV normal to elevated levels are expected.
and/or with Indication in HCM is based on arterial
other sedatives vasoconstriction, decreasing heart rate, which
in combination improves diastolic filling and reduces
(acepromazine, myocardial oxygen consumption.
butorphanol, Contraindicated in systemic hypertension.
ketamine, Rare cases of post- administration pulmonary
other) edema; monitor respiratory character and
Drug Formulary administration; cats should be fasted prior to
rate. Vomiting may occur within minutes after
dosing. Raises ventricular diameter in dogs
(alters echo results) and same is anecdotally
observed in cats, reducing appearance of LV
thickening and possibly conveying appearance
of systolic dysfunction. Largely replaced by
dexmedetomidine.

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