III. OTHER POSITIVE INOTROPIC DRUGS
Amrinone, dobutamine, and dopamine are "non-digitalis positive in-
otropic drugs" currently approved for short-term use in congestive
Pharmacokinetics (see also
* Absorption: These drugs are approved for parenteral use only.
* Elimination: Amrinone is eliminated by both hepatic and renal mechan-
isms. Dobutamine and dopamine are both catecholamines and are metabol-
ized by catechol-O-methyltransferase (COMT). Dopamine is also metabol-
ized by monoamine oxidase (MAO).
These digitalis substitutes are not approved for any other uses and
unlabelled uses are insignificant at present.
Contraindications and Warnings
* Obstructive cardiomyopathy
* Digitalis toxicity
* Ventricular arrhythmias
* Sympathomimetic toxicity, eg, pheochromocytoma
(PgDn key for more text)
Adverse Reactions and Toxicities
- Hematologic: thrombocytopenia.
- GI: nausea, vomiting, abdominal pain, hepatotoxicity.
- CV: arrhythmias, hypotension.
- Treatment: Monitor platelet count; reduce dosage or stop drug if
platelet count drops below 150000/mm3.
- CV: hypotension, tachycardia, angina, arrhythmia
- Miscellaneous: headache, gi distress, shortness of breath.
- CV: arrhythmias, tachycardia, angina, hypertension
- Miscellaneous: nausea and vomiting, headache, dyspnea
* MAO inhibitors: potentiate dopamine and to a lesser extent,
* Halogenated hydrocarbon anesthetics: sensitize the myocardium to the
arrhythmogenic actions of the positive inotropic agents.
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