2 Cardiovascular Medications

How cardiovascular medicines are selected

Cardiovascular medicines may lower blood pressure, reduce the heart’s workload, prevent clots, control rhythm, or improve heart-failure outcomes. The appropriate medicine depends on the diagnosis, blood pressure, heart rate, kidney function, other medicines, and treatment goals. The medication groups below have distinct roles and risks; their use is individualized rather than interchangeable.

Heart-failure medicines

For HFrEF, four medication groups form the foundation of guideline-directed therapy: an ARNI or, when that is unsuitable or not tolerated, an ACE inhibitor or ARB; an evidence-based beta blocker; an MRA; and an SGLT2 inhibitor. Diuretics may be added when fluid congestion is present. These therapies are generally introduced and adjusted as tolerated, with decisions guided by symptoms, blood pressure, kidney function, and laboratory results.

• ARNI: Sacubitril/valsartan is a preferred renin–angiotensin system option for many people with symptomatic HFrEF. Risks include low blood pressure, increased potassium, kidney-function changes, and rare angioedema. It must not be combined with an ACE inhibitor; a clinician-directed washout period is required when switching from an ACE inhibitor.

• ACE inhibitors and ARBs: Examples include lisinopril or enalapril, and losartan or valsartan. They may be used when an ARNI is unsuitable or not tolerated, and for other indications such as hypertension or care after myocardial infarction. Risks include low blood pressure, kidney-function changes, and high potassium; ACE inhibitors can also cause cough or angioedema. Avoid these medicines in pregnancy. Do not combine an ACE inhibitor with an ARB or an ARNI.

• Evidence-based beta blockers: Carvedilol, metoprolol succinate, and bisoprolol improve outcomes in stable HFrEF and also treat some rhythm and blood-pressure conditions. Risks include slow heart rate, low blood pressure, and fatigue. Starting or increasing one inappropriately may worsen acute decompensated heart failure. Do not stop suddenly without clinical guidance.

• MRAs: Spironolactone and eplerenone reduce risk in eligible people with HFrEF. They can cause high potassium and worsening kidney function, so potassium and renal function should be checked before and during treatment. Spironolactone can cause breast tenderness or enlargement.

• SGLT2 inhibitors: Dapagliflozin and empagliflozin benefit many people with HFrEF, whether or not they have diabetes. Risks include dehydration, genital infections, and uncommon ketoacidosis. Review kidney function, volume status, and sick-day or perioperative instructions.

• Diuretics: Furosemide and torsemide relieve fluid overload, such as swelling or breathlessness. Risks include dehydration, low blood pressure, kidney-function changes, and electrolyte loss; monitor weight, symptoms, kidney function, and electrolytes as directed. Diuretics relieve congestion but are not a substitute for HFrEF medicines that improve outcomes.

Blood pressure and angina

Several medication groups can reduce blood pressure or relieve angina, but their effects and cautions differ.

• Calcium-channel blockers: Amlodipine relaxes arteries and is commonly used for hypertension or angina. Verapamil and diltiazem also slow conduction through the heart and may be used for selected rate-control or angina indications. These medicines can cause low blood pressure and ankle swelling; verapamil and diltiazem can slow the pulse and may worsen some forms of systolic heart failure. They should not be used to treat an undiagnosed wide-complex tachycardia.

• Nitrates: Nitroglycerin can relieve angina by widening blood vessels. It may cause headache, flushing, dizziness, or dangerously low blood pressure. Never combine nitrates with PDE-5 erectile-dysfunction medicines such as sildenafil, tadalafil, or vardenafil, or with certain medicines for pulmonary hypertension, because the combination can cause severe hypotension. Follow prescribed instructions, but seek emergency help for possible heart-attack symptoms rather than delaying care to see whether the medicine works.

• Other antihypertensives: Thiazide diuretics and other vasodilators may be used depending on the condition. Selection and monitoring depend on blood pressure, kidney function, electrolytes, and coexisting disease.

Arrhythmias and clot prevention

Rate and rhythm control

Beta blockers, diltiazem, or verapamil may slow the ventricular rate in atrial fibrillation (AF) or other selected rhythms. The choice depends on ventricular function, blood pressure, and the rhythm. Combining medicines that slow the rate can cause excessive bradycardia or heart block.

Antiarrhythmics such as amiodarone, sotalol, or flecainide are used for specific rhythm-control situations. They can cause dangerous rhythm changes or affect other organs. Choosing one requires attention to ECG findings, heart structure, kidney function, electrolytes, and interactions. These medicines are not interchangeable or appropriate for every rhythm.

Preventing and treating clots

Anticoagulants—including apixaban, rivaroxaban, dabigatran, edoxaban, and warfarin—reduce clot-related stroke risk in many people with AF and prevent or treat other clots. Choice and dose depend on the indication, kidney function, interactions, and individual factors; bleeding is a major risk. Warfarin requires INR monitoring and consistent vitamin-K intake, while direct oral anticoagulants require adherence and interaction review. Do not stop an anticoagulant or change its dose without prescriber guidance. Aspirin is not a substitute when anticoagulation is indicated for AF.

Acute coronary syndrome and myocardial infarction

Treatment for acute coronary syndrome (ACS), including myocardial infarction, commonly includes antiplatelet therapy, an anticoagulant in appropriate acute-care settings, and high-intensity statin therapy. Aspirin combined with a P2Y12 inhibitor—such as clopidogrel, ticagrelor, or prasugrel—is called DAPT. It lowers the risk of recurrent clotting but increases bleeding risk; the treatment combination and duration are individualized.

After ACS, clinicians may also use a beta blocker, ACE inhibitor, ARB, ARNI, or other medicines according to the patient’s condition and contraindications. These medicines complement, but do not replace, urgent assessment and reperfusion treatment when needed.

• Antiplatelets: Watch for unusual bruising, blood in urine or stool, vomiting blood, or persistent bleeding. Tell clinicians about these medicines before procedures. Do not stop DAPT after a stent unless the treating team directs it.

• Statins: Atorvastatin and rosuvastatin lower LDL cholesterol and cardiovascular risk. Report unexplained severe muscle pain or weakness, and review potential interactions. A lipid panel is commonly rechecked after starting or adjusting lipid-lowering treatment.

• Nitrates: These may relieve ischemic chest discomfort when appropriate, but must not delay emergency evaluation. They are unsafe with PDE-5 inhibitors or certain other interacting drugs.

Emergency rhythm treatment

Emergency treatment depends on the documented rhythm and the patient’s stability. Assessment, monitoring, and treatment of the cause are priorities. If a tachyarrhythmia causes hypotension, shock, altered mental status, ischemic chest discomfort, or acute heart failure, synchronized cardioversion is generally the urgent treatment; medication is not a reason to delay it.

Adenosine is reserved for selected regular rhythms. Drug choice for wide-complex rhythms depends on the protocol, and verapamil and diltiazem can be harmful in wide-complex tachycardia. These are clinician-level interventions, not self-treatment instructions.

Safe medication use and emergencies

Use medicines consistently and as prescribed. Do not double a missed dose unless the medication’s instructions say to do so. If a dose is missed or side effects occur, ask the prescriber or pharmacist what to do.

• Verify the medication, dose, route, time, and patient against the prescription or clinical order. Use an up-to-date medication list that includes over-the-counter medicines and supplements.

• Check relevant measurements and laboratory tests as directed: blood pressure and pulse for medicines that lower rate or pressure; kidney function and potassium for renin–angiotensin system medicines, MRAs, and many diuretics; INR for warfarin; and ECG or other monitoring for selected antiarrhythmics.

• Screen for interactions and contraindications. Important examples include nitrates with PDE-5 inhibitors, combinations of ACE inhibitors, ARBs, and ARNI, and multiple medicines that slow heart rate or increase bleeding.

• Do not stop beta blockers, anticoagulants, antiplatelets after stenting, or heart-failure medicines on your own.

Seek emergency services promptly for new or severe chest pressure, fainting, severe shortness of breath, signs of stroke, or a sustained rapid or irregular heartbeat with weakness or confusion. Do not drive yourself if seriously unwell.

Across cardiovascular treatment, benefits depend on choosing the appropriate medication group and using it safely, with attention to blood pressure, pulse, kidney function, electrolytes, bleeding, interactions, and clear instructions. For an unstable arrhythmia or suspected heart attack, emergency assessment and definitive treatment take priority over self-administered medication.