Page 428 - Feline Cardiology

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

Lidocaine Amide Na-channel 0.25–1 mg/kg Main indication is ventricular arrhythmias: 20 mg/ml
(Xylocaine [H], blocking (class Ib) IV slowly PVCs, ventricular tachycardia. Recommend (2% soln)
lignocaine) local anesthetic starting at bolus of 0.25–1 mg/kg, to be VM,HM
repeated up to 2 mg/kg total dose. If this
effectively breaks the ventricular tachycardia,
a CRI should be continued, since half-life is
very short. IV bolus required to achieve
therapeutic levels quickly, as there would be a
delay of several hours for therapeutic effect if
+
just using a CRI. Ensure that serum [K ] is
normal; hypokalemia both triggers PVCs/VT
and makes them refractory to lidocaine. Cats
reported to be sensitive to CNS adverse effects
of lidocaine; monitor mentation when
administering. Goal of treatment is
hemodynamically adequate rhythm (i.e.,
acceptable pulse quality, alertness, reduction
in syncopal episodes), which does not
necessarily equate to a normal ECG.
Mechanism:binds to sodium channels
following depolarization, prolonging
repolarization. Result is more homogeneous
electrical activity, i.e., antiarrhythmic effect.
Adverse effects in cats may be neurologic
(acute depression, ataxia, seizures) or
cardiovascular (hypotension, collapse).
Constant rate infusion may be administered at
10–15 mcg/kg/min. Sample formulation for
10 mcg/kg/min: 2.5 ml (50 mg) in 100 ml 5%
dextrose = 500 mcg/ml. Administration at half
maintenance rate = 30 ml/kg/d = 1.25 ml/
kg/h = 0.02 ml/kg/min = 10 mcg/kg/min. Begin
at lower end of dosage range and adjust
according to response. May be preceded by IV
propranolol administration in VT, in the
absence of CHF, hypotension, or severe
myocardial failure. Analgesic use (e.g., as part
of morphine-lidocaine-ketamine infusion) not
recommended in cats due both to risk of
toxicity and demonstrated lack of analgesia
when administered IV.
Lisinopril Angiotensin- 0.25–0.5 mg/ Adjunctive treatment (with diuretic) of 2.5, 5,
(Prinivil [H], converting kg congestive heart failure. Historical interest in 10, 20,
Zestril [H]) enzyme [ACE] PO q 24h large dogs due to lower cost; availability of 30, 40 mg
inhibitor other ACE inhibitors with feline-specific Tab
information or equally low cost now makes HM
this drug of little use in cats.

Lopressor—see
Metoprolol Drug Formulary
Lotensin—see
Benazepril
Continued

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