Dopamine has different effects at precise dosage levels: At low dosage, 1-3mcg/kg/min it has dopaminergic properties that result in vasodilitation of renal, messenteric, and cerebral arteries. At dosages between 3-10mcg/kg/min it has beta-1 properties, similar to dobutamine. Greater than 10mcg/kg/min it has Alpha properties used to treat hypotension
Renal Perfusion: 1-3mcg/kg/min
Beta Range: 3-10mcg/kg/min
Alpha Range: 10-20mcg/kg/min
Greater than 20mcg/kg/min: May switch to norepinephrine .
Negative chronotropic effect. Diltiazem causes a modest lowering of heart rate, and reduces myocardium oxygen consumption. This effect is used to depress the frequency of hyperactive tissue causing arrhythmias.
Negative inotropic effect. Diltiazem causes a modest decrease in contractility. This effect is due to slowing of the SA node. It results in reduced myocardium oxygen consumption.
Negative dromotropic effect. By slowing conduction through the AV node, diltiazem increases the time needed for each beat. This results in reduced myocardium oxygen consumption.
If patients are given the drug without a break in therapy for more than a day they can develop tolerance.
Severe myocardial ischemia leading to infarction or death may occur after abrupt withdrawal of long-term nitrate therapy.
Oral nitroglycerin undergoes significant first-pass metabolism and has less than 1% oral bioavailability. The sublingual route is effective for the treatment of acute attacks of angina, and is preferred in order to avoid first-pass metabolism.
Give 2.5-5.0 mg IV bolus over 2 min; repeat doses of 5-10 mg may be given every 15-30 min.
Hypotension, especially in hypovolemic patients. Other reactions include myocardial depression, heart failure, dizziness, headache, nausea and vomiting, bradycardia, complete AV block, and peripheral (dependent) edema.
Give Calcium Chloride as reversal agent for Verapamil.
Guidelines for Pacemakers and Defibrillators Updated. Journal Watch General Medicine 1998: 2-2.
Wood, D.A., Fox, K.F., Gibbs, S.R. (2001). Rapid cardiology--for chest pain, breathlessness and palpitations. QJ Med 94: 177-178.
HAMMILL, S. C., HUBMAYR, R. D. (2000). The Rapidly Changing Management of Cardiac Arrhythmias. Am J Respir Crit Care Med 161: 1070-1073.
Bauersfeld, U., Nowak, B., Molinari, L., Malm, T., Kampmann, C., Schonbeck, M. H., Schuller, H. (1999). Low-energy epicardial pacing in children: the benefit of autocapture. Ann. Thorac. Surg. 68: 1380-1383.
KURBAAN, A S, SUTTON, R (1999). Pacing for vasovagal syncope. Heart 82: 649-650
Braunwall, e. (1992) Heart Disease : a textbook of cardiovascular disease, 4 th edition, WB Saunders
American Radio Relay League, Inc., Technical Information Service, 225 Main St., Newington, CT 06111 (860) 594-0214.
Thelan, Lynne A., Davie, Joseph K., Urden, Linda D., Lough, Mary E. (1994) Critical Care Nursing: Diagnosis and Management. Second Edition. Pg 313-322.
Graver, K (1998) A Practical Guide to EKG Interpretation, 2 nd edition