Overview
DESCRIPTION Clonidine hydrochloride, USP is a centrally acting alpha-agonist hypotensive agent available as tablets for oral administration in three dosage strengths: 0.1 mg, 0.2 mg, and 0.3 mg. The 0.1 mg tablet is equivalent to 0.087 mg of the free base. The following inactive ingredients are contained in these products: corn starch, D&C Yellow #10 Aluminum Lake, FD&C Yellow #6 Aluminum Lake...
Mechanism of Action
CLINICAL PHARMACOLOGY Clonidine stimulates alpha-adrenoreceptors in the brain stem. This action results in reduced sympathetic outflow from the central nervous system and in decreases in peripheral resistance, renal vascular resistance, heart rate, and blood pressure. Clonidine hydrochloride tablets act relatively rapidly. The patient’s blood pressure declines within 30 to 60 minutes after an oral dose, the maximum decrease occurring within 2 to 4 hours. Renal blood flow and glomerular filtration rate remain essentially unchanged. Normal postural reflexes are intact; therefore, orthostatic symptoms are mild and infrequent.
Indications
- INDICATIONS AND USAGE Clonidine hydrochloride tablets are indicated in the treatment of hypertension. Clonidine hydrochloride tablets may be employed alone or concomitantly with other antihypertensive agents.
Common Doses
- 0.1 mg
- 0.2 mg
- 0.6 mg
- 2.4 mg
Dosage
DOSAGE AND ADMINISTRATION Adults: The dose of clonidine hydrochloride tablets must be adjusted according to the patient’s individual blood pressure response. The following is a general guide to its administration. Initial Dose: 0.1 mg tablet twice daily (morning and bedtime). Elderly patients may benefit from a lower initial dose. Maintenance Dose: Further increments of 0.1 mg per day may be made at weekly intervals if necessary until the desired response is achieved.
Contraindications
- CONTRAINDICATIONS Clonidine hydrochloride tablets should not be used in patients with known hypersensitivity to clonidine (see PRECAUTIONS ).
Side Effects
- ADVERSE REACTIONS Most adverse effects are mild and tend to diminish with continued therapy. The most frequent (which appear to be dose-related) are dry mouth, occurring in about 40 of 100 patients; drowsiness, about 33 in 100; dizziness, about 16 in 100; constipation and sedation, each about 10 in 100. The following less frequent adverse experiences have also been reported in patients receiving clonidine hydrochloride tablets, but in many cases patients were receiving concomitant medication and a causal relationship has not been established.
Interactions
- Drug Interactions Clonidine may potentiate the CNS-depressive effects of alcohol, barbiturates or other sedating drugs. If a patient receiving clonidine hydrochloride is also taking tricyclic antidepressants, the hypotensive effect of clonidine may be reduced, necessitating an increase in the clonidine dose. If a patient receiving clonidine is also taking neuroleptics, orthostatic regulation disturbances (e.g., orthostatic hypotension, dizziness, fatigue) may be induced or exacerbated.