Can one add captopril (Angiotensin-Converting Enzyme Inhibitor) for emergency hypertension when already taking an Angiotensin Receptor Blocker (ARB)?

From the Guidelines

No, it is generally not recommended to add captopril for emergency hypertension when already taking an ARB (Angiotensin Receptor Blocker). Both captopril (an ACE inhibitor) and ARBs work on the renin-angiotensin-aldosterone system (RAAS) 1. Using them together can lead to excessive blockade of this system, potentially causing severe hypotension, hyperkalemia, and acute kidney injury. For emergency hypertension in a patient already on an ARB, consider alternative medications such as:

• Intravenous labetalol (20-80 mg bolus, followed by infusion if needed)
• Intravenous hydralazine (10-20 mg)
• Intravenous nicardipine (initial rate 5 mg/hour, titrate up to 15 mg/hour) These medications work through different mechanisms and are safer to use in combination with ARBs. Always monitor blood pressure, heart rate, and kidney function closely when treating emergency hypertension. If oral medication is preferred, consider adding a calcium channel blocker like amlodipine (5-10 mg) or a thiazide diuretic like hydrochlorothiazide (12.5-25 mg) to the existing ARB regimen, rather than introducing another RAAS inhibitor. The most recent guidelines from the American College of Cardiology/American Heart Association 1 and the European Society of Cardiology 1 support this approach, emphasizing the importance of avoiding dual RAAS blockade and instead opting for alternative agents that do not increase the risk of adverse effects. Key considerations in managing emergency hypertension include:
• The type and severity of hypertensive emergency
• The presence of underlying organ damage or comorbidities
• The need for close monitoring of blood pressure, heart rate, and kidney function
• The selection of appropriate medications that balance efficacy with safety. In general, the goal is to reduce blood pressure in a controlled manner, avoiding rapid or excessive decreases that could lead to complications 1.

From the Research

Hypertensive Emergency and Angiotensin-Converting Enzyme Inhibitors

• In cases of hypertensive emergency, the goal is to reduce blood pressure rapidly to prevent target-organ damage 2.
• The reduction in blood pressure should be tailored to the specific situation, with a recommended reduction of mean arterial pressure by no more than 25% during the first hour 2.
• Parenteral medication, such as urapidil, verapamil, and nitroglycerin, may be applied in hypertensive crisis, while sublingual nifedipine and captopril may be used in states with endangering hypertensive crisis 3.

Adding Captopril to Angiotensin Receptor Blocker (ARB) Therapy

• There is no direct evidence to suggest that adding captopril (an Angiotensin-Converting Enzyme Inhibitor) to an ARB is contraindicated in emergency hypertension 4, 3, 2, 5, 6.
• However, the management of hypertensive emergency or urgency depends on the specific situation, and the choice of antihypertensive medication should be individualized based on the patient's condition and medical history 3, 6.
• In general, the treatment of hypertensive emergency or urgency involves a combination of antihypertensive medications, including renin-angiotensin system inhibitors, thiazide diuretics, and calcium channel blockers 4.

Considerations for Treatment

• The severity of the condition, rather than the absolute blood pressure level, determines the need for urgent treatment 6.
• Patients with hypertensive emergency should be treated in an intensive care setting with close monitoring of blood pressure and organ function 2, 6.
• The goal of treatment is to reduce blood pressure rapidly, but not to normal values, to prevent target-organ damage 2, 6.