From the Guidelines
Clonidine is generally reserved as a last-line antihypertensive medication due to its significant CNS adverse effects, especially in older adults, and should be used with caution 1. When considering clonidine for hypertension management, it's crucial to weigh its benefits against potential risks. The medication works by stimulating alpha-2 adrenergic receptors in the brain, which decreases sympathetic outflow and subsequently reduces heart rate and blood pressure. Key points to consider when prescribing clonidine include:
- The usual dose range is 0.1–0.8 mg/day, divided into 2 doses, with the option for a transdermal patch releasing 0.1–0.3 mg daily for 7 days 1.
- Abrupt discontinuation of clonidine must be avoided to prevent rebound hypertension; instead, the dosage should be tapered gradually under medical supervision 1.
- Common side effects include drowsiness, dry mouth, dizziness, constipation, and sedation, which can significantly impact the patient's quality of life.
- Clonidine may interact with other blood pressure medications, CNS depressants, and certain antidepressants, necessitating careful monitoring and adjustment of the treatment regimen.
- Regular blood pressure monitoring is essential while using clonidine to ensure its effectiveness and to minimize potential adverse effects.
From the FDA Drug Label
Clonidine hydrochloride tablets, USP are indicated in the treatment of hypertension. Clonidine hydrochloride tablets, USP may be employed alone or concomitantly with other antihypertensive agents. 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.
Key Points:
- Clonidine is used to treat hypertension.
- It can be used alone or with other antihypertensive agents.
- Clonidine is a centrally acting alpha-agonist hypotensive agent.
- It is available in oral tablet form in three dosage strengths: 0.1 mg, 0.2 mg, and 0.3 mg 2, 2.
From the Research
Overview of Clonidine
- Clonidine is an antihypertensive medication that has been used to treat attention-deficit/hyperactivity disorder (ADHD) in children and adolescents 3, 4, 5.
- It is an α(2)-adrenergic agonist that can reduce heart rate and blood pressure 6, 7.
Efficacy in ADHD
- Clonidine has been shown to improve symptoms of ADHD in children and adolescents, with a moderate effect size of 0.58 +/- 0.16 (95% confidence interval = 0.27-0.89) 5.
- It can be used as monotherapy or as an adjunct to stimulant regimens, with significant reductions in ADHD rating scale IV (ADHD-RS-IV) total scores achieved at week 5 4.
- Symptomatic improvement of ADHD can be achieved following 2 weeks' treatment with clonidine 4.
Safety and Tolerability
- Clonidine is generally well tolerated, but common side effects include drowsiness, sedation, fatigue, and somnolence 3, 4, 7, 5.
- It can cause bradycardia, with more incidents of bradycardia in subjects treated with clonidine compared to those not treated with clonidine (17.5% versus 3.4%; p = .02) 3.
- Reductions in heart rate and blood pressure are modest and rarely lead to discontinuation of treatment 7.
Cardiovascular Effects
- Clonidine may reduce heart rate and blood pressure, whereas psychostimulants can increase heart rate and blood pressure 6.
- There is concern about the safety of psychostimulant and nonpsychostimulant medications in patients with ADHD, but studies have not consistently shown a disproportionately high risk of major adverse cardiovascular outcomes 6.