What is the recommended dosing of Arkamin (clonidine) for an adult with hypertension?

Arkamin (Clonidine) Dosing for Hypertension

Clonidine is reserved as a last-line agent for resistant hypertension only after failure of first-line agents (ACE inhibitors/ARBs, calcium channel blockers, and thiazide diuretics), and typically after spironolactone. 1, 2, 3

Position in Treatment Algorithm

Clonidine should never be used as initial therapy for hypertension due to significant CNS adverse effects, particularly in older adults. 1, 3 The treatment sequence before considering clonidine is:

1. First-line agents: ACE inhibitor/ARB + calcium channel blocker or thiazide diuretic 1
2. Three-drug combination: RAS blocker + dihydropyridine CCB + thiazide/thiazide-like diuretic 1
3. Spironolactone 25-50 mg daily 2
4. Clonidine only after all above steps fail 2

FDA-Approved Dosing

Initial Dose

• 0.1 mg twice daily (morning and bedtime) 4
• Elderly patients: Lower initial dose recommended, starting at 0.05 mg twice daily 4, 5

Maintenance Dose

• Increase by 0.1 mg per day at weekly intervals until desired response 4
• Usual therapeutic range: 0.2-0.6 mg/day in divided doses 4
• Maximum effective dose: 2.4 mg/day (rarely needed) 4
• Taking the larger portion at bedtime minimizes dry mouth and drowsiness 4

Renal Impairment

• Lower initial dose recommended with careful monitoring 4
• No supplemental dose needed after hemodialysis 4

Acute/Severe Hypertension Protocol

For rapid blood pressure control in severe hypertension (when oral route is appropriate):

• Loading dose: 0.2 mg initially 6, 7
• Subsequent doses: 0.1 mg hourly until BP controlled or maximum 0.8 mg total 6, 7, 8
• Average effective dose: 0.26-0.5 mg 6, 7, 8
• Average response time: 1.8-2 hours 6, 8

Critical caveat: This rapid titration approach is from older studies and should only be used in monitored settings, as immediate-release nifedipine is now preferred for acute severe hypertension in outpatient settings. 9

Safety Parameters

Hold Clonidine If:

• Systolic BP <90 mmHg 2
• Diastolic BP <60 mmHg 2
• Heart rate <50 bpm 2
• Orthostatic hypotension present 2

Monitoring Requirements

• Check BP and heart rate before each dose 2
• Assess for orthostatic changes, especially in elderly 2
• Monthly follow-up until BP controlled (within 3 months) 2

Critical Safety Warnings

Rebound Hypertension Risk

Never abruptly discontinue clonidine - this can precipitate severe hypertensive crisis. 1, 2, 3 Gradual tapering is mandatory when stopping therapy. 1, 2

Common Adverse Effects

• Sedation and somnolence (most common CNS effect) 2
• Dry mouth 2, 8
• Dizziness, headache, fatigue 2
• Hypotension (especially with rapid dose escalation) 2

Practical Implementation

• Scheduled daily dosing with excellent adherence is mandatory 3
• Transdermal formulation (0.1-0.3 mg weekly patch) preferred over oral to maintain steady levels and reduce withdrawal risk 1, 3
• Concurrent diuretic therapy typically required for optimal control 5, 8
• Target BP reduction: At least 20/10 mmHg from baseline 2

Common Pitfalls to Avoid

• Do not use clonidine as first-line therapy - violates all major guidelines 1, 3
• Never prescribe PRN - creates life-threatening rebound risk 3
• Do not discharge without clear follow-up plan when initiating therapy 9
• Avoid excessive BP reduction - can cause organ hypoperfusion 2, 9