METHYLDOPA tablet film coated

Country: United States

Language: English

Source: NLM (National Library of Medicine)

Active ingredient:

METHYLDOPA (UNII: 56LH93261Y) (METHYLDOPA ANHYDROUS - UNII:M4R0H12F6M)

Available from:

Teva Pharmaceuticals USA Inc

INN (International Name):

METHYLDOPA

Composition:

METHYLDOPA ANHYDROUS 250 mg

Prescription type:

PRESCRIPTION DRUG

Authorization status:

Abbreviated New Drug Application

Summary of Product characteristics

METHYLDOPA- METHYLDOPA TABLET, FILM COATED
TEVA PHARMACEUTICALS USA INC
----------
METHYLDOPA TABLETS USP
2931
2932
DESCRIPTION
Methyldopa USP is an antihypertensive drug.
Methyldopa USP is the L-isomer of alpha-methyldopa. Its chemical name
is levo-3-(3,4-
dihydroxyphenyl)- 2-methylalanine sesquihydrate. Its structural
formula is:
C
H NO • 1
/
H O M.W. 238.24
Methyldopa USP is a white to yellowish white, odorless fine powder and
is sparingly soluble in water.
Each tablet, for oral administration, contains 250 mg or 500 mg of
methyldopa USP. Potency is
calculated in the anhydrous basis. Inactive ingredients: calcium
sulfate (anhydrous), citric acid
(anhydrous), colloidal silicon dioxide, edetate disodium (dihydrate),
ethyl cellulose, hydroxypropyl
cellulose, hypromellose, magnesium stearate, methylcellulose,
polyethylene glycol, sodium starch
glycolate, talc, and titanium dioxide.
CLINICAL PHARMACOLOGY
Methyldopa is an aromatic-amino-acid 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
acceleration. In some pat