From the Guidelines
Clonidine can be an effective treatment for tachycardia, particularly when associated with hypertension, anxiety, or withdrawal symptoms, as it reduces sympathetic nervous system activity and slows heart rate. According to the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1, clonidine is a central alpha-2 agonist that can be used to treat hypertension, and its ability to slow heart rate makes it a potential treatment for tachycardia. The usual dose of clonidine for hypertension is 0.1-0.8 mg orally twice daily, and it is generally reserved as a last-line treatment due to significant CNS adverse effects, especially in older adults.
When using clonidine to treat tachycardia, it is essential to:
- Start with a low dose and gradually increase as needed to avoid excessive blood pressure lowering
- Monitor blood pressure and heart rate regularly during treatment
- Avoid abrupt discontinuation, as this can lead to rebound hypertension and tachycardia
- Consult with a healthcare provider before starting or adjusting any medication regimen, especially for patients with underlying cardiovascular conditions
Some key points to consider when using clonidine for tachycardia include:
- Clonidine's ability to slow heart rate stems from its action as an alpha-2 adrenergic agonist, which decreases norepinephrine release from sympathetic nerve endings
- Clonidine can be associated with significant CNS adverse effects, especially in older adults
- Clonidine should be tapered off rather than suddenly discontinued to avoid rebound hypertension and tachycardia, as noted in the clinical practice guideline for the diagnosis, evaluation, and treatment of attention-deficit/hyperactivity disorder in children and adolescents 1
Overall, clonidine can be a useful treatment for tachycardia, but its use should be carefully considered and monitored by a healthcare provider, especially in patients with underlying cardiovascular conditions.
From the FDA Drug Label
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. Slowing of the pulse rate has been observed in most patients given clonidine, but the drug does not alter normal hemodynamic response to exercise.
Clonidine can help resolve tachycardia by slowing the pulse rate, as it has been observed in most patients given the medication. This effect is due to its action on alpha-adrenoreceptors in the brain stem, which reduces sympathetic outflow and leads to decreases in heart rate. 2
From the Research
Tachycardia Treatment with Clonidine
- Clonidine, an antihypertensive medication, has been used to treat various conditions, including hypertension, drug withdrawal, and anxiety 3, 4.
- In the context of tachycardia, clonidine has been shown to reduce heart rate by stimulating central alpha receptors, which diminishes efferent sympathetic tone to the heart 5, 6.
- A study on tizanidine withdrawal reported that a patient with tachycardia improved with oral clonidine treatment, suggesting its potential use in resolving tachycardia in certain cases 3.
- Clonidine's hemodynamic effects include reduction in heart rate, total peripheral resistance, and plasma renin activity, with little effect on resting cardiac output 7, 6.
- However, abrupt withdrawal of clonidine has been reported to cause rebound hypertension, tachycardia, and cardiac arrhythmias, highlighting the importance of gradual tapering when discontinuing the medication 7.
Clonidine's Mechanism of Action
- Clonidine stimulates central alpha-2 adrenergic and imidazoline receptors, decreasing norepinephrine release and resulting in reduced blood pressure and heart rate 3, 4.
- Its mechanism of action also involves increasing vagal activity, which contributes to its antihypertensive and heart rate-lowering effects 6.
- Clonidine's versatility and efficacy in treating hypertension, as well as its potential use in managing tachycardia, make it a valuable medication in various clinical settings 4, 5, 6.