Editing Pharmacology (section)

=== Cardiovascular ===

* '''ACE inhibitors''' (lisinopril): lower blood pressure and reduce cardiac remodeling. Adverse effects: persistent dry cough, hyperkalemia, first-dose hypotension, acute kidney injury, and rarely angioedema, which is an emergency. Contraindicated in pregnancy. If cough is intolerable, an angiotensin receptor blocker is the usual substitute.
* '''ARBs''' (losartan): similar profile without the cough. Still cause hyperkalemia and are contraindicated in pregnancy.
* '''Beta blockers''' (metoprolol, atenolol, carvedilol): decrease heart rate, contractility, and blood pressure. Hold and notify for apical pulse under 60 or systolic blood pressure under 90 unless otherwise ordered. Never stop abruptly because rebound tachycardia, hypertension, and angina can occur. Use caution in asthma with nonselective agents. Beta blockers '''mask''' the tachycardia and tremor of hypoglycemia, which is a key teaching point in diabetes.
* '''Calcium channel blockers''': dihydropyridines (amlodipine, nifedipine) act mainly on vessels and cause peripheral edema, flushing, and headache. Nondihydropyridines (verapamil, diltiazem) also slow the heart rate and are used for rate control. Verapamil commonly causes constipation. Grapefruit juice raises levels.
* '''Diuretics''': loop diuretics (furosemide, bumetanide) are potent and cause hypokalemia, hyponatremia, hypomagnesemia, hypocalcemia, dehydration, and ototoxicity when pushed rapidly. Give intravenous furosemide slowly. Thiazides (hydrochlorothiazide) cause hypokalemia, hyperglycemia, hyperuricemia, and hypercalcemia. Potassium-sparing agents (spironolactone, triamterene) cause '''hyper'''kalemia; spironolactone also causes gynecomastia. Teach patients to take diuretics in the morning to avoid nocturia and to weigh daily, reporting a gain of 2 to 3 pounds in a day or about 5 pounds in a week.
* '''Digoxin''': positive inotrope, negative chronotrope. Therapeutic serum range is roughly 0.5 to 2.0 ng/mL, with 0.5 to 0.9 ng/mL targeted in heart failure. Take the apical pulse for a full minute and hold for a rate under 60 in an adult. Early toxicity presents as anorexia, nausea, vomiting, fatigue, visual disturbance including yellow-green halos, and dysrhythmias. '''Hypokalemia potentiates digoxin toxicity''', so watch potassium closely in patients also taking loop diuretics. The antidote is digoxin immune Fab.
* '''Nitrates''' (nitroglycerin): venodilation reduces preload and relieves angina. Sublingual dosing for an outpatient is one tablet, repeated every 5 minutes up to three doses, with emergency services called per current guidance if pain is unrelieved. Expect headache. Absolutely contraindicated with phosphodiesterase-5 inhibitors such as sildenafil or tadalafil because of profound hypotension. Hold for systolic blood pressure under 90. Transdermal nitrates require a nitrate-free interval, typically 10 to 12 hours, to prevent tolerance.
* '''Statins''': lower low-density lipoprotein. Monitor for myalgia and, rarely, rhabdomyolysis; teach patients to report unexplained muscle pain, tenderness, weakness, or dark urine. Monitor liver enzymes at baseline. Avoid grapefruit juice with simvastatin, lovastatin, and atorvastatin. Contraindicated in pregnancy.
* '''Antidysrhythmics''': amiodarone is broadly effective but causes pulmonary toxicity, thyroid dysfunction (both hypo and hyper), hepatotoxicity, corneal microdeposits, blue-gray skin discoloration, and QT prolongation. Adenosine is given as a rapid intravenous push followed immediately by a saline flush and produces a brief period of asystole.
* '''Vasoactive infusions''' (registered nurse scope): norepinephrine, dopamine, epinephrine, phenylephrine, vasopressin, nitroglycerin drip, nitroprusside, and dobutamine are titrated to a hemodynamic target. Give through a central line when possible because extravasation of a vasoconstrictor causes tissue necrosis; the antidote for that extravasation is phentolamine infiltrated locally. Nitroprusside carries a risk of cyanide and thiocyanate toxicity with prolonged or high-dose use and must be protected from light.