From the Guidelines
Clonidine is not typically used for hypertensive crisis due to its slow onset of action, but if used, the dose is 150-300 mcg i.v. bolus in 5-10 minutes.
Key Points
- The onset of action of Clonidine is 30 minutes, which is slower compared to other medications listed, such as Esmolol, Metoprolol, and Nitroprusside, which have an onset of action of 1-5 minutes 1.
- The duration of action of Clonidine is 4-6 hours, which is comparable to other medications like Labetalol and Enalaprilat 1.
- The dose of Clonidine for hypertensive crisis is 150-300 mcg i.v. bolus in 5-10 minutes, but it is not the preferred choice due to its slow onset of action 1.
- Clonidine can cause sedation and rebound hypertension as adverse effects, which should be carefully monitored 1.
- Other medications like Nitroglycerine, Nitroprusside, and Urapidil may be more suitable for hypertensive crisis due to their faster onset of action and more predictable effects 1.
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. The therapeutic doses most commonly employed have ranged from 0.2 mg to 0.6 mg per day given in divided doses. Studies have indicated that 2. 4 mg is the maximum effective daily dose, but doses as high as this have rarely been employed.
The FDA drug label does not answer the question.
From the Research
Dose and Frequency of Clonidine for Hypertensive Crisis
- The initial oral dose of clonidine hydrochloride is 0.1 to 0.2 mg, followed by hourly doses of 0.05 or 0.1 mg until goal blood pressure is attained, or a total of 0.7 mg is given 2.
- Another study suggests an initial dose of 0.2 mg, followed by 0.1 mg each hour until a dose of 0.7 mg has been given, or the diastolic blood pressure reaches a predetermined goal 3.
- A "loading" dose of 0.2 mg clonidine, followed by 0.1 mg hourly until the blood pressure is substantially reduced, or until a total dose of 0.8 mg has been administered, has also been used 4.
Administration and Efficacy
- Oral clonidine loading is safe and effective in the management of hypertensive urgencies and emergencies, with a significant reduction in blood pressure achieved in 93% of patients 2.
- The average dose of clonidine required to achieve acceptable blood pressure control is 0.45 mg 3 to 0.5 mg 4.
- Intramuscular administration of clonidine has also been shown to be safe and effective, with a dose-related response 5.
Comparison with Other Treatments
- The use of short-acting agents, such as clonidine, for hypertensive urgency has been shown to worsen outcomes, and therefore should be avoided in the office 6.
- A protocol and algorithm developed by clinical pharmacists to manage hypertensive urgencies, which included avoiding short-acting antihypertensives like clonidine, reduced the number of clonidine orders and hospital admissions 6.