País: Estados Unidos
Idioma: inglés
Fuente: NLM (National Library of Medicine)
METHYLDOPA (UNII: 56LH93261Y) (METHYLDOPA ANHYDROUS - UNII:M4R0H12F6M)
Bryant Ranch Prepack
METHYLDOPA
METHYLDOPA ANHYDROUS 500 mg
PRESCRIPTION DRUG
Abbreviated New Drug Application
METHYLDOPA- METHYLDOPA TABLET, FILM COATED BRYANT RANCH PREPACK ---------- METHYLDOPA TABLETS, USP RX ONLY DESCRIPTION Methyldopa is an antihypertensive and is the L-isomer of alpha-methyldopa. It is levo-3-(3,4- dihydroxyphenyl)-2-methylalanine sesquihydrate. Methyldopa is supplied as tablets for oral administration, containing 125 mg, 250 mg and 500 mg of methyldopa. The amount of methyldopa is calculated on the anhydrous basis. Its molecular formula is C H NO • 1 1/2 H , with a molecular weight of 238.24, and its structural formula is: Methyldopa is a white to yellowish white, odorless fine powder and is sparingly soluble in water. The tablets contain the following inactive ingredients: pregelatinized starch, sodium starch glycolate, povidone, microcrystalline cellulose, magnesium stearate, hypromellose, FD&C yellow #6 lake and titanium dioxide. In addition 125 mg and 250 mg tablets contain corn starch. CLINICAL PHARMACOLOGY Methyldopa is an aromatic-aminoacid decarboxylase inhibitor in animals and in man. Although the mechanism of action has yet to be conclusively demonstrated, the antihypertensive effect of methyldopa probably is due to its metabolism to alpha-methylnorepinephrine, which then lowers arterial pressure by stimulation of central inhibitory alpha-adrenergic receptors, false neurotransmission, and/or reduction of plasma renin activity. Methyldopa has been shown to cause a net reduction in the tissue concentration of serotonin, dopamine, norepinephrine, and epinephrine. Only methyldopa, the L-isomer of alpha-methyldopa, has the ability to inhibit dopa decarboxylase and to deplete animal tissues of norepinephrine. In man, the antihypertensive activity appears to be due solely to the L-isomer. About twice the dose of the racemate (DL-alpha-methyldopa) is required for equal antihypertensive effect. Methyldopa has no direct effect on cardiac function and usually does not reduce glomerular filtration rate, renal blood flow, or filtration fraction. Cardiac output usually is maintained without cardiac Leer el documento completo