From the Guidelines
Clonidine is a centrally-acting alpha-2 adrenergic agonist that should be used with caution, primarily for hypertension, and reserved as a last-line treatment due to significant CNS adverse effects, especially in older adults, with a typical starting dose of 0.1 mg twice daily, and a maximum daily dose of 0.8 mg divided throughout the day 1. For hypertension, the dosing can be gradually increased every 2-4 weeks until blood pressure is controlled.
- The medication works by stimulating alpha-2 receptors in the brain, reducing sympathetic outflow and decreasing peripheral vascular resistance, heart rate, and blood pressure.
- Common side effects include dry mouth, drowsiness, dizziness, and constipation.
- Patients should never stop clonidine suddenly as this can cause dangerous rebound hypertension; doses must be gradually tapered over 2-4 days.
- The medication can be taken with or without food, and the transdermal patch form (Catapres-TTS) provides weekly dosing as an alternative to oral tablets. In addition to hypertension, clonidine has applications for ADHD, opioid withdrawal symptoms, menopausal hot flashes, and certain pain conditions, with different dosing regimens, such as starting at 0.1 mg tablet at bedtime for ADHD, which can then be increased to a twice-daily administration and subsequent careful uptitration, with doses higher than 0.4 mg/day not recommended 1. However, the primary focus for clonidine use remains its antihypertensive effects, and its use in other conditions should be carefully considered based on the most recent and highest quality evidence available.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION Adults The dose of clonidine hydrochloride tablets, USP must be adjusted according to the patient’s individual blood pressure response. INDICATIONS AND USAGE Clonidine hydrochloride tablets, USP are indicated in the treatment of hypertension. The uses of clonidine include the treatment of hypertension. The dosages of clonidine are as follows:
- Initial Dose: 0.1 mg tablet twice daily (morning and bedtime)
- Maintenance Dose: Further increments of 0.1 mg per day may be made at weekly intervals if necessary until the desired response is achieved
- Therapeutic Doses: 0.2 mg to 0.6 mg per day given in divided doses 2 Clonidine may be employed alone or concomitantly with other antihypertensive agents 2
From the Research
Uses of Clonidine
- Clonidine is used to treat hypertension, including essential hypertension and refractory hypertension 3
- It is also used to treat attention deficit and hyperactivity disorders (ADHD) in children and adolescents, both as monotherapy and as adjunctive therapy with stimulant medications 4, 5
- Clonidine is used in the management of acute hypertensive urgency in hospitalized older people 6
Dosages of Clonidine
- The dosage of clonidine varies depending on the condition being treated and the patient's response to the medication
- For hypertension, clonidine can be used alone or in combination with other antihypertensive agents, such as diuretics, beta-blockers, and alpha-methyldopa 3
- For ADHD, clonidine extended-release is approved for use in children, and the dosage is typically titrated to achieve optimal efficacy and tolerability 4, 5
- In hospitalized older people, clonidine is often used on an as-needed basis for acute management of hypertension, with the dosage adjusted based on the patient's blood pressure response 6
Efficacy and Safety
- Clonidine has been shown to be effective in reducing blood pressure in patients with hypertension, and in improving symptoms of ADHD in children and adolescents 3, 4, 5
- Clonidine is generally well-tolerated, but common side effects include somnolence, fatigue, headache, bradycardia, and hypotension 4, 6
- Serious cardiac side effects, including death, have been reported in rare cases, particularly in patients with underlying heart disease or other risk factors 4