GENERIC NAME: carvedilol
BRAND NAME: Coreg
DRUG CLASS AND MECHANISM: Carvedilol is used for treating high blood pressure and congestive heart failure. It is related to labetalol (Normodyne, Trandate). Carvedilol blocks receptors of the adrenergic nervous system, the system of nerves in which epinephrine (adrenalin) is active. Nerves from the adrenergic system enter the heart and release an adrenergic chemical (norepinephrine) that attaches to receptors on the heart's muscle and stimulates the muscle to beat more rapidly and forcefully. By blocking the receptors, carvedilol reduces the heart's rate and force of contraction and thereby reduces the work of the heart. Carvedilol also blocks adrenergic receptors on arteries and causes the arteries to relax and the blood pressure to fall. The drop in blood pressure further reduces the work of the heart since it is easier to pump blood against a lower pressure. The FDA first approved carvedilol in 1995.
GENERIC AVAILABLE: yes
PREPARATION: Tablets, 3.125mg, 6.25mg, 12.5mg, and 25mg.
STORAGE: Tablets should be stored at room temperature, 15- 30 C (59-86 F).
PRESCRIBED FOR: Carvedilol is used by itself or with a diuretic ("water-pill") to control high blood pressure. Carvedilol also may be used in combination with other drugs to manage mild or moderate congestive heart failure. When combined with other treatments for heart disease among patients with recent heart attacks, carvedilol can reduce the risk of a second heart attack by 40% and increase survival among patients with congestive heart failure.
DOSING: Carvedilol usually is given twice daily. For high blood pressure, the dose may range from 6.25mg twice daily to a maximum of 25mg twice daily. For congestive heart failure, the dose may range from 3.25mg twice daily to a maximum of 25mg twice daily in persons weighing less than 85kg (187 pounds) or 50mg twice daily in persons weighing more than 85kg (187 pounds). Carvedilol should be taken with food since this increases the amount of absorbed drug that reaches the heart and arteries. Stopping and changing doses of carvedilol should be done under the direction of a physician since sudden changes in dose can result in serious cardiac complications such as arrhythmias.
DRUG INTERACTIONS: Carvedilol can mask early warning symptoms of hypoglycemia (low blood sugar) such as tremors and increased heart rate. (These symptoms are caused by activation of the adrenergic nervous system which is blocked by the carvedilol.) Therefore, patients with diabetes taking medications that lower blood sugar such as insulin or oral anti-diabetic medications may need to increase the frequency with which they monitor their blood sugar.
Reserpine, monoamine oxidase inhibitors (phenelzine or isocarboxazid) and clonidine (Catapres), because they have similar mechanisms of action as carvedilol, may greatly accentuate the effects of carvedilol and cause a steep decline in blood pressure and/or heart rate. Close monitoring of blood pressure and heart rate may be needed.
Carvedilol may cause an increase in digoxin (Lanoxin) blood levels. Therefore, in patients receiving digoxin, the digoxin blood level should be monitored if carvedilol is started, adjusted or discontinued.
Rifampin (Rifadin) can sharply decrease the carvedilol blood level. Therefore, in patients taking rifampin, the dose of carvedilol may need to be increased.
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