What is a suitable initial antihypertensive medication for a patient with a history of substance (drug) use?

Initial Antihypertensive Medication for Patients with History of Drug Use

For patients with a history of substance use, an angiotensin receptor blocker (ARB) such as losartan is the most appropriate initial antihypertensive medication due to its favorable side effect profile and once-daily dosing that promotes adherence.

First-Line Medication Selection

• ARBs like losartan are recommended as first-line agents for patients with substance use history due to their minimal side effects, low potential for drug interactions, and once-daily dosing that enhances adherence 1
• The usual starting dose of losartan is 50 mg once daily, which can be increased to a maximum of 100 mg once daily as needed to control blood pressure 2
• For patients who might be volume depleted (common in substance users), a lower starting dose of 25 mg is recommended 2

Rationale for ARB Selection in Substance Users

• ARBs have minimal central nervous system effects and do not cause sedation or cognitive impairment that could trigger substance cravings 3
• Unlike beta-blockers, ARBs don't have potential contraindications related to substance use such as cocaine-induced tachyarrhythmias 3
• ARBs have no dose-dependent increase in side effects, making them more tolerable than thiazide diuretics, beta-blockers, and calcium channel blockers 3
• Losartan specifically has been shown to be very well tolerated with dizziness being the only drug-related event reported more frequently than placebo 4

Alternative Options Based on Specific Substances

• For patients using stimulants (cocaine, amphetamines):

  • Avoid beta-blockers as they can lead to unopposed alpha-adrenergic stimulation with stimulant use 3
  • Calcium channel blockers like nicardipine may be particularly useful for hypertensive emergencies induced by stimulants 3

• For patients with alcohol use disorder:

  • ACE inhibitors like enalapril may be considered as they don't have significant interactions with alcohol 5
  • Starting dose should be 2.5 mg under medical supervision if the patient might be volume depleted from alcohol use 5

Monitoring Considerations

• For patients on ARBs or ACE inhibitors, monitor serum creatinine/estimated glomerular filtration rate and potassium levels at least annually 3
• More frequent monitoring may be necessary in patients with substance use disorders due to potential fluctuations in hydration status and electrolyte balance 3

Common Pitfalls to Avoid

• Avoid simultaneous use of ACE inhibitors, ARBs, and/or renin inhibitors as this combination is potentially harmful 3
• Beta-blockers should be avoided in patients using cocaine or other stimulants due to risk of paradoxical hypertension 3
• Medications requiring multiple daily doses may lead to poor adherence in patients with substance use disorders 1
• Central-acting agents like clonidine should be used cautiously due to potential for rebound hypertension if doses are missed, which is more common in patients with substance use disorders 3

Treatment Algorithm

1. First choice: Start with losartan 50 mg once daily (25 mg if potentially volume depleted) 2
2. If inadequate response: Increase losartan to 100 mg once daily 2
3. If still inadequate: Add a thiazide diuretic like hydrochlorothiazide 12.5 mg 3
4. If combination therapy needed from start (BP ≥160/100 mmHg): Begin with losartan 50 mg plus hydrochlorothiazide 12.5 mg 1

By selecting an ARB like losartan for patients with substance use history, you provide effective blood pressure control with minimal side effects and a simple dosing regimen that promotes adherence, ultimately reducing morbidity and mortality related to hypertension in this challenging patient population.