Cardiovascular Pharmacology
Here we'll learn which drugs are used to treat common cardiovascular disorders; because there are so many of them, antiarrhythmic drugs are discussed separately.
Hypertension
- First, indicate that the goal of these drugs is to reduce blood volume, systemic vascular resistance, or cardiac output, so as to return the blood pressure to normal.
- Many patients will require combination therapy to achieve these goals.
Vasodilation reduces systemic vascular resistance:
Angiotensin-converting-enzyme inhibitors (ACE inhibitors)*:
– These drugs tend to end in
"pril" (ex: Lisinopril, benazapril, captopril), and are considered first line therapy; additionally, they protect against diabetic kidney disease, which makes them particularly useful in patients with hypertension and diabetes mellitus.
– However, they are not recommended as first line therapy in patients with asthma (because they can cause coughing), and that they are contraindicated in pregnancy and bilateral renal stenosis.
Angiotensin II receptor blockers (ARBs)*:
– Often end in "sartan" (ex: candesartan, azilsartan, eprosartan, etc.).
– As their name suggests, these drugs block the angiotensin II receptors on blood vessels, thereby prohibiting the vasoconstrictor effects of angiotensin II.
– Like ACE inhibitors, these drugs should not be used in pregnancy or by patients with bilateral renal stenosis; however, they are suitable for patients with asthma, as they are not associated with respiratory side effects.
Calcium channel blockers*:
– Predominantly act on the vessels to produce vasodilation are the dihydropyridines; the specific drugs end in "pine" (ex: felodipine, nifedipine, amlodipine, etc.).
Write that these are another example of first line therapy for hypertensive patients, and evidence suggests that they are particularly effective in elderly and African American individuals.
Hydralazine* (brand name: Apresoline):
– Sometimes used to treat severe hypertension, and, as we'll see, hypertension during pregnancy.
Cardiac Output Reduction
Beta-blockers*:
– End in "lol" (ex: metoprolol, acebutolol, bioprolol, labetalol, etc.).
– These drugs block norepinephrine and epinephrine receptors on blood vessels.
– Because of their effects on the heart, beta blockers are contraindicated in patients with bradycardia and AV nodal block.
– Be aware that, in patients with diabetes, beta blockers can mask signs of low blood sugar;
– And, non-selective beta blockers should not be prescribed to patients with asthma or COPD, because they can induce bronchoconstriction.
Increase Urine Output
Thiazide diuretics*:
– Typically end in
"ide" (ex: chlorothiazide, indapamide, etc.), and thiazide-like diuretics.
– Thiazide diuretics are another example of first line therapy, but be aware that they
should not be given to patients with sulfa allergies.
Aldosterone antagonists*:
– End in "one" (spironolactone and eplerenone) are used in
resistant hypertension, and are contraindicated in pregnancy.
Hypertensive Emergency
- Defined as systolic BP > 180 mmHg or diastolic BP > 120 mmHg with acute organ damage.
- Nitrates (ex: nitroprusside and nitroglycerine)
- Calcium channel blockers (ex: clevidipine and nicardipine)
- Dopamine-1 – agonists (fenoldopam)
- Adrenergic blockers (labetalol)
Hypertension during Pregnancy
- Methyldopa
- Labetalol
- Nifedipine
- Hydralazine
Hypotension
- Hypotension medications work to increase cardiac output and/or systemic vascular resistance.
- Vasoconstrictors include alpha-agonists; examples include methoxamine and phenylephrine.
- Cardiostimulatory drugs used to increase cardiac output include beta-agonists, which increase heart rate and contractility; examples include norepinephrine and dopamine.
Heart Failure w/ Reduced Ejection Fraction
- Treatment objectives are to improve cardiac functioning and relieve symptoms.
Increase urine output to lower blood volume:
– Diuretics
– Aldosterone antagonists
Vasodilators:
– ACE inhibitors
– ARBs
Cardioinhibitory drugs
– Beta-blockers (once the patient is stable)
– Ivabradine, which is a sinus node inhibitor that is prescribed to patients with persistent heart rate above 70 beats per minute, despite treatment with beta blockers.
Inotropic drugs
– Digitalis (ex: digoxin), may be given to some patients to improve cardiac contractility and cardiac output.
Digitalis should not be given to patients with hypokalemia, sinus or AV block, or reduced renal function.
- Be aware that there are no proven medication strategies for treating heart failure with preserved ejection fraction.
Angina
- The objective of treatment is to reduce the ratio of oxygen demand to supply in order to reduce the symptoms and improve prognosis.
Vasodilator
– Nitroglycerine is used to prevent and treat sudden attacks; nitroglycerine be administered sublingually, orally, or transdermally.
Cardioinhibitory drugs reduce contractility and heart rate, and include:
– Beta-blockers
– Non-dihydropyridine calcium channel blockers, verapamil and diltiazem, which are more cardio-selective than are the dihydropyridine calcium channel blockers used to treat hypertension.
Ranolazine
– A late sodium current blocker, ranolazine, is also sometimes prescribed; this drug decreases heart wall tension and improves coronary blood flow.
Anti-thrombotic drugs
– Anti-platelets and anti-coagulants may be prescribed to reduce clotting and improve blood flow.
Myocardial infarction
- Therapeutic goal is to reduce the ratio of oxygen demand to oxygen supply.
Restore coronary blood flow
– Thrombolytic and antiplatelet drugs
Vasodilators
– Nitroglycerine
Reduce oxygen demand
– Beta blockers
- Other drugs may also be used to alleviate pain and MI complications, including morphine, anti-arrhythmics, and diuretics.
Be aware that the medications we've learned here may not be appropriate in all cases, and that other interventions, such as lifestyle changes and surgical procedures, may also be necessary. Furthermore, be aware that underlying disease states, such as dyslipidemia, may need to be addressed.
For references, please see full tutorial on Cardiovascular Pharmacology
