0.1 mg tablet twice daily (morning and bedtime). Elderly patients may benefit from a lower initial dose.
The usual daily dosage of methyldopa is 500 mg to 2 g in two to four doses.
Clonidine is rarely used solely as an antihypertensive agent, because other more effective antihypertensives are available. However, clonidine could be an excellent choice for a patient with a combination of hypertension, pain, and anxiety.
Also known as a centrally acting alpha agonists, alpha 2 receptor agonists, alpha 2 inhibitors, and central adrenergic inhibitors, these drugs work by decreasing stimulatory sensors from the brain and central nervous system. They stop nerve impulses in the brain which would cause excitement. They also excite a pathway which will inhibit the response of stimulating nerve endings. This causes the patient to be very relaxed and the blood vessels to be very relaxed.
Centrally acting sympatholytics block sympathetic activity by binding to and activating alpha2 (α2)-adrenoceptors. This reduces sympathetic outflow to the heart thereby decreasing cardiac output by decreasing heart rate and contractility. Reduced sympathetic output to the vasculature decreases sympathetic vascular tone, which causes vasodilation and reduced systemic vascular resistance, which decreases arterial pressure.
Central alpha agonists are used to treat hypertension, opioid dependence, alcohol addiction, menopause symptoms, ADHD, spasticity, and fibromyalgia. They work by lowering blood pressure, reducing hot flashes, and relieving withdrawal symptoms, and controlling impulsive behavior.
The a-2 adrenergic agonists are a class of drugs used to treat multiple, distinctively different, conditions. They are used to treat pain, opioid, benzodiazepine and alcohol withdrawal, symptoms of cigarette craving, high blood pressure, attention-deficit/hyperactivity disorder and panic disorder.