3.2 Cardiovascular and Anticoagulant Medications
Key Takeaways
- Antihypertensives include ACE inhibitors (-pril), ARBs (-sartan), beta-blockers (-olol), calcium channel blockers (-dipine), and diuretics.
- Statins (-statin) lower cholesterol by inhibiting HMG-CoA reductase and should generally be taken at bedtime.
- Warfarin requires INR monitoring; direct oral anticoagulants (DOACs) like apixaban and rivaroxaban do not require routine monitoring.
- Antiplatelet agents (aspirin, clopidogrel) prevent clot formation by inhibiting platelet aggregation.
- Nitroglycerin for chest pain should be stored in original glass container away from light and heat.
Quick Answer: Cardiovascular drugs treat heart disease, hypertension, and blood clotting disorders. Key classes include antihypertensives (ACE inhibitors, ARBs, beta-blockers), statins for cholesterol, and anticoagulants (warfarin, DOACs) for blood clot prevention.
Antihypertensive Medications
ACE Inhibitors (Suffix: -pril)
| Generic Name | Brand Name | Key Points |
|---|---|---|
| lisinopril | Prinivil, Zestril | Most commonly prescribed ACE inhibitor |
| enalapril | Vasotec | Available in IV form |
| ramipril | Altace | Used post-MI for heart protection |
| benazepril | Lotensin | Often combined with diuretics |
Common Side Effects: Dry cough, hyperkalemia, angioedema Contraindication: Pregnancy (teratogenic)
ARBs (Angiotensin II Receptor Blockers - Suffix: -sartan)
| Generic Name | Brand Name | Key Points |
|---|---|---|
| losartan | Cozaar | Can be used when ACE inhibitor cough occurs |
| valsartan | Diovan | Available in multiple combination products |
| irbesartan | Avapro | Used in diabetic nephropathy |
| olmesartan | Benicar | High potency |
Common Side Effects: Hyperkalemia, dizziness Contraindication: Pregnancy
Beta-Blockers (Suffix: -olol)
| Generic Name | Brand Name | Key Points |
|---|---|---|
| metoprolol | Lopressor, Toprol XL | Cardioselective (beta-1); most prescribed |
| atenolol | Tenormin | Cardioselective; once daily dosing |
| propranolol | Inderal | Non-selective; also used for anxiety/tremors |
| carvedilol | Coreg | Also blocks alpha receptors |
Common Side Effects: Bradycardia, fatigue, cold extremities, masking hypoglycemia symptoms Caution: Do not stop abruptly (can cause rebound hypertension)
Calcium Channel Blockers (CCBs)
| Type | Generic Name | Brand Name | Key Points |
|---|---|---|---|
| Dihydropyridine (-dipine) | amlodipine | Norvasc | Most commonly used; long-acting |
| Dihydropyridine | nifedipine | Procardia, Adalat | Avoid grapefruit juice |
| Non-dihydropyridine | diltiazem | Cardizem, Tiazac | Slows heart rate |
| Non-dihydropyridine | verapamil | Calan, Verelan | Slows heart rate; constipation common |
Key Drug Interaction: Grapefruit juice increases blood levels of many CCBs
Diuretics
| Type | Generic Name | Brand Name | Key Points |
|---|---|---|---|
| Thiazide | hydrochlorothiazide (HCTZ) | Microzide | First-line; may cause hypokalemia |
| Loop | furosemide | Lasix | Potent; "ceiling effect" |
| Loop | bumetanide | Bumex | 40x more potent than furosemide |
| Potassium-sparing | spironolactone | Aldactone | Can cause hyperkalemia; gynecomastia |
| Potassium-sparing | triamterene | Dyrenium | Often combined with HCTZ (Dyazide) |
Cholesterol-Lowering Medications (Statins - Suffix: -statin)
| Generic Name | Brand Name | Key Points |
|---|---|---|
| atorvastatin | Lipitor | High potency; most prescribed statin |
| simvastatin | Zocor | Take at bedtime; grapefruit interaction |
| rosuvastatin | Crestor | High potency; water-soluble |
| pravastatin | Pravachol | Fewer drug interactions |
| lovastatin | Mevacor | Take with evening meal |
Mechanism: Inhibit HMG-CoA reductase enzyme in liver Side Effects: Muscle pain (myalgia), elevated liver enzymes, rhabdomyolysis (rare but serious) Monitoring: Liver function tests, lipid panel
Storage Note: Most statins are stable at room temperature but check individual product requirements.
Anticoagulant Medications
Warfarin
| Detail | Information |
|---|---|
| Brand Name | Coumadin, Jantoven |
| Mechanism | Vitamin K antagonist |
| Monitoring | INR (International Normalized Ratio) |
| Target INR | 2.0-3.0 for most conditions; 2.5-3.5 for mechanical heart valves |
| Antidote | Vitamin K (phytonadione) |
Key Drug/Food Interactions:
- Vitamin K-rich foods (green leafy vegetables) decrease effect
- Many drugs interact (antibiotics, NSAIDs, amiodarone)
Direct Oral Anticoagulants (DOACs)
| Generic Name | Brand Name | Mechanism | Key Point |
|---|---|---|---|
| apixaban | Eliquis | Factor Xa inhibitor | Twice daily; renal adjustment needed |
| rivaroxaban | Xarelto | Factor Xa inhibitor | Take with evening meal; once daily |
| dabigatran | Pradaxa | Direct thrombin inhibitor | Store in original container; requires renal function |
| edoxaban | Savaysa | Factor Xa inhibitor | Once daily |
Advantages over Warfarin: No routine INR monitoring, fewer food interactions, fixed dosing
Heparins
| Type | Generic Name | Administration | Monitoring |
|---|---|---|---|
| Unfractionated heparin (UFH) | heparin | IV or SubQ | aPTT |
| LMWH | enoxaparin (Lovenox) | SubQ only | Anti-Xa (if needed) |
| LMWH | dalteparin (Fragmin) | SubQ only | Usually not required |
Antidote: Protamine sulfate
Antiplatelet Medications
| Generic Name | Brand Name | Mechanism | Key Points |
|---|---|---|---|
| aspirin | Various | COX inhibitor | Low dose (81mg) for prevention |
| clopidogrel | Plavix | P2Y12 inhibitor | Used with aspirin after stent |
| prasugrel | Effient | P2Y12 inhibitor | More potent; higher bleeding risk |
| ticagrelor | Brilinta | P2Y12 inhibitor | Twice daily; reversible |
Cardiac Glycoside
| Generic Name | Brand Name | Key Points |
|---|---|---|
| digoxin | Lanoxin | Narrow therapeutic index; monitor levels |
Therapeutic Range: 0.5-2.0 ng/mL Signs of Toxicity: Nausea, visual disturbances (yellow-green halos), arrhythmias Antidote: Digoxin immune Fab (Digibind)
Nitrates for Angina
| Generic Name | Brand Name | Form | Key Points |
|---|---|---|---|
| nitroglycerin | Nitrostat (SL), Nitro-Dur (patch) | Sublingual, transdermal | Headache common; remove patch at night |
| isosorbide mononitrate | Imdur | Oral | Once daily; take in morning |
| isosorbide dinitrate | Isordil | Oral | Multiple daily doses |
Storage for Nitroglycerin SL: Keep in original dark glass container; replace every 6 months once opened; do not store in plastic
ACE Inhibitors vs ARBs
Both lower blood pressure by acting on the renin-angiotensin system, but they differ in side effects and stems.
| Class | Stem | Example | Hallmark Side Effect |
|---|---|---|---|
| ACE inhibitor | -pril | lisinopril, enalapril | Dry cough, hyperkalemia, angioedema |
| ARB | -sartan | losartan, valsartan | Used when ACE cough is intolerable |
Exam Tip: A persistent dry cough is the classic ACE-inhibitor side effect; switching to an ARB resolves it. Both classes are contraindicated in pregnancy.
Beta Blockers, CCBs, and Diuretics
| Class | Stem / Example | Key Points |
|---|---|---|
| Beta blocker | -olol (metoprolol, atenolol) | Lowers heart rate; do not stop abruptly |
| Calcium channel blocker | amlodipine, diltiazem | Peripheral edema; "-dipine" relaxes vessels |
| Thiazide diuretic | hydrochlorothiazide | First-line for HTN; monitor potassium |
| Loop diuretic | furosemide (Lasix) | Potent; can lower potassium |
| Potassium-sparing | spironolactone | Raises potassium; caution with ACE/ARB |
Exam Trap: Combining an ACE inhibitor or ARB with a potassium-sparing diuretic raises the risk of hyperkalemia. This is a high-yield interaction to flag for the pharmacist.
Anticoagulant Monitoring and Antidotes
Anticoagulants prevent clot formation and are high-alert medications. Each has a specific reversal agent.
| Drug | Class | Monitoring | Antidote |
|---|---|---|---|
| warfarin (Coumadin) | Vitamin K antagonist | INR | Vitamin K (phytonadione) |
| heparin | Indirect thrombin inhibitor | aPTT | Protamine sulfate |
| enoxaparin (Lovenox) | LMWH | Usually none | Protamine (partial) |
| apixaban, rivaroxaban | DOAC (factor Xa inhibitor) | None routinely | Andexanet alfa |
| dabigatran | Direct thrombin inhibitor | None routinely | Idarucizumab |
Worked Example: A patient on warfarin has an elevated INR and bleeding. The reversal agent is vitamin K, and for rapid reversal, the antidote pairing is warfarin to vitamin K. Knowing each anticoagulant's antidote is a frequent exam item.
Warfarin interacts with many drugs and with vitamin-K-rich foods (leafy greens). Patients should keep vitamin K intake consistent rather than eliminating it.
A patient develops a persistent dry cough after starting lisinopril. The prescriber will most likely switch the patient to:
What is the antidote for warfarin?
Combining an ACE inhibitor with a potassium-sparing diuretic such as spironolactone increases the risk of: