Page 23 - RxExam's Naplex Theory Review Part-1

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4. CENTRALLY ACTING ANTIHYPERTENSIVES

Classification:

Aldomet = Methyldopa
Clonidine = Catapres, Catapres TTS, Kapvay, Jenloga,
Nexiclon XR, Duraclon
Guanfacine = Tenex, Intuniv
Guanabenz = Wytensin

Dose Special Notes

Methyldopa 250 mg to 2 1). Methyldopa (Aldomet) metabolites to alpha-methyl norepinephrine
(Tablet) grams per day in which stimulates alpha-2 adrenergic receptors. The stimulation of
(Injection) two to four alpha-2 receptor prevents the release of noradrenaline. It also reduces
(Oral divided doses. the plasma renin activity. It is indicated for the treatment of
suspension) hypertension.

2). Prolonged therapy with Methyldopa (Aldomet) may produce the
positive Comb’s test. If Comb’s test positive hemolytic anemia occurs,
the therapy should be discontinued. Anemia may remit promptly upon
discontinuation of the drug.

3). Fever should be reported if it occurs within one month of initiating
the therapy. If jaundice, liver enzyme elevation or hepatic necrosis is
reported, patients should discontinue the therapy. CBC and monitoring
of liver and renal functions should be done from time to time during the
therapy.

4). Because of a shorter duration of action of Methyldopa (Aldomet),
sudden withdrawal or discontinuation of the drug may produce severe
hypertensive crisis. A physician should withdraw drug slowly.

5). Oral suspension of Methyldopa (Aldomet) may produce
hypersensitivity reaction due to the presence of sodium bisulfite.

6). Methyldopa (Aldomet) may cause discoloration of urine. Sedation,
lightheadedness, hypotension, hemolytic anemia, hepatitis and
jaundice are also reported with the therapy.

Clonidine 0.1 to 0.3 mg PO 1). Clonidine (Catapres) is an alpha-2 receptor AGONIST that prevents
(Tablet) BID. the release of noradrenaline. It is indicated for the treatment of
(Tablet, ER) hypertension.
(Extended 2). Catapres TTS is a transdermal system of Clonidine. It is available in
release oral 0.1mg, 0.2mg or 0.3mg of strength. Each transdermal system delivers
suspension), 0.1mg, 0.2mg or 0.3mg of Clonidine per day for a week.
(TDS)

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