Pharmacology II Exam 2: Cardiovascular, Renal, and Hematologic Medications

Comprehensive vocabulary flashcards covering cardiovascular, renal, and hematologic pharmacology, including RAAS inhibitors, beta blockers, calcium channel blockers, diuretics, lipid-lowering agents, antiarrhythmics, anticoagulants, antidotes, and safety parameters.

Heart Rate Assessment Threshold

Normal adult resting heart rate is $60\text{ to }100\text{ beats/min}$. For heart-slowing drugs (beta blockers, verapamil, diltiazem, digoxin, antiarrhythmics), assess the apical pulse for $1\text{ full minute}$ and hold the medication if the heart rate is under $60\text{ beats/min}$, then notify the provider.

Serum Potassium Range

The normal reference range is $3.5\text{ to }5.0\text{ mEq/L}$ (noted as $3.5\text{ to }5.3\text{ mEq/L}$ in course materials). Values under $3.5\text{ mEq/L}$ indicate hypokalemia (flat T waves, U waves, muscle cramps), while values over $5.0\text{ mEq/L}$ indicate hyperkalemia (peaked T waves, dysrhythmias).

Therapeutic Digoxin Level

The course therapeutic range is $0.6\text{ to }1.2\text{ ng/mL}$ (with general reference texts stating $0.5\text{ to }2.0\text{ ng/mL}$). A level of $>1.2\text{ ng/mL}$ (such as $2.8\text{ to }2.9\text{ ng/mL}$) is toxic and requires holding the drug and notifying the provider immediately.

Coagulation Monitoring Goals (INR and aPTT)

The therapeutic goal for warfarin therapy is an INR of usually $2\text{ to }3$ (or $2.5\text{ to }3.5$ for mechanical heart valves). For heparin therapy, the therapeutic aPTT goal is usually $1.5\text{ to }2.5\text{ times the control}$.

Alpha-1 ($\alpha_1$) Receptor

A peripheral adrenergic receptor switch whose stimulation squeezes (constricts) blood vessels, driving blood pressure up.

Alpha-2 ($\alpha_2$) Receptor

A central adrenergic regulatory receptor whose activation calms sympathetic nerve signals, allowing blood pressure to decrease.

Beta-1 ($\beta_1$) Receptor

An adrenergic receptor located primarily in the heart ("1 heart") whose activation causes the heart to beat faster (chronotropic) and squeeze harder (inotropic).

Beta-2 ($\beta_2$) Receptor

An adrenergic receptor located primarily in the lungs ("2 lungs") whose stimulation dilates and opens the airways to ease breathing.

RAAS Cascade Inhibitor Targets

A pathway targeting blood pressure regulation at four key points: aliskiren blocks renin (start of chain); captopril blocks ACE enzyme; losartan blocks the AT1 receptor; and eplerenone blocks aldosterone (salt/water retention). All four raise serum potassium.

Hydrochlorothiazide (HCTZ)

A thiazide diuretic acting in the early distal tubule to block sodium-chloride reabsorption. First-line for hypertension and mild edema. Adverse effects include hypokalemia ($<3.5\text{ mEq/L}$, leg cramps, dysrhythmias), hyponatremia, dehydration, elevated glucose, elevated uric acid (gout), and elevated calcium.

Captopril

An ACE inhibitor that prevents the conversion of angiotensin I to angiotensin II, causing vasodilation and decreased aldosterone secretion. Key adverse effects include a persistent dry cough, angioedema (swelling of lips, tongue, face, throat; airway emergency), hyperkalemia, and fetal harm in pregnancy. Administer $1\text{ hour}$ before meals.

Losartan

An angiotensin II receptor blocker (ARB) that blocks AT1 receptors on blood vessels. Used for hypertension, heart failure, and diabetic nephropathy when ACE-inhibitor cough is intolerable. Causes hyperkalemia and renal impairment; contraindicated in pregnancy; avoid potassium supplements and potassium-based salt substitutes.

Aliskiren

A direct renin inhibitor that halts the RAAS pathway at the very first step. Can cause diarrhea, hyperkalemia, angioedema, and fetal harm. Avoid high-fat meals (decreases absorption) and never combine with ACE inhibitors or ARBs in patients with diabetes.

Nifedipine

A dihydropyridine calcium channel blocker that selectively relaxes arterial smooth muscle without slowing the heart rate. Common side effects include peripheral ankle edema, headache, flushing, and reflex tachycardia. Extended-release tablets must not be crushed; immediate-release forms must not be used for hypertensive emergencies.

Verapamil

A non-dihydropyridine calcium channel blocker (Class IV antiarrhythmic) that slows AV node conduction and dilates vessels. Used for hypertension, angina, and supraventricular arrhythmias. Major adverse effect is severe constipation ("Vera can't poop"), bradycardia, and heart block. Increases digoxin levels.

Diltiazem

A non-dihydropyridine calcium channel blocker (Class IV antiarrhythmic) that slows AV node conduction and relaxes coronary and peripheral vessels. Used for atrial fibrillation rate control, SVT, and hypertension. Causes bradycardia, heart block, and peripheral edema, but with less constipation than verapamil.

Metoprolol

A cardioselective beta-1 adrenergic antagonist that slows heart rate and lowers blood pressure. Used for hypertension, angina, post-MI, and heart failure. Adverse effects include bradycardia, heart block, fatigue, and masking symptoms of hypoglycemia. Higher doses can lose selectivity and cause bronchospasm in asthma.

Propranolol

A nonselective beta-adrenergic blocker (Class II antiarrhythmic) that blocks both beta-1 (heart) and beta-2 (lungs) receptors. Used for hypertension, arrhythmias, migraines, and stage fright. Contraindicated in asthma and COPD due to the risk of life-threatening bronchospasm. Can cause orthostatic hypotension and mask hypoglycemia.

Carvedilol

A nonselective beta and alpha-1 blocker that causes both peripheral vasodilation and cardiac slowing. Used for heart failure and hypertension. Must be taken with food to decrease orthostatic dizziness. Adverse effects include profound orthostatic hypotension, bradycardia, bronchospasm, and masked hypoglycemia.

Sodium Nitroprusside

A potent direct IV vasodilator that relaxes arteries and veins within seconds for hypertensive emergencies. Metabolized by the liver into cyanide. Dangers include profound hypotension, cyanide toxicity (confusion, acidosis, collapse), and thiocyanate toxicity (tinnitus). Must be given by IV pump, monitored via arterial line, and protected from light.

Eplerenone

A selective aldosterone receptor antagonist that spares potassium while causing sodium and water excretion. Used for hypertension and post-MI heart failure. Lacks the significant antiandrogenic side effects of spironolactone (less gynecomastia), but hyperkalemia remains the priority danger.

Doxazosin

An alpha-1 adrenergic receptor blocker (-zosin) that relaxes vascular smooth muscle and the bladder neck/prostate tissue. Used to treat hypertension and benign prostatic hyperplasia (BPH). Major risk is first-dose orthostatic hypotension and syncope; initial dose must be administered at bedtime.

Epinephrine

A nonselective catecholamine agonist (alpha-1, beta-1, beta-2) used as first-line treatment for anaphylaxis, cardiac arrest, and severe bronchospasm. Constricts blood vessels, accelerates cardiac output, and opens airways. Administered intramuscularly into the outer thigh for anaphylaxis. May cause tachycardia, chest pain, and transient hyperglycemia.

Dobutamine

A beta-1 selective adrenergic agonist that increases myocardial contractility (positive inotrope) with minimal heart rate acceleration. Used for short-term management of acute cardiogenic shock and low-output heart failure. Requires continuous ECG, blood pressure, and IV site monitoring; cannot pump an empty fluid tank.

Sacubitril / Valsartan

An ARNI (angiotensin receptor neprilysin inhibitor) combining an ARB with a neprilysin inhibitor to boost natriuretic peptides (BNP) and relax vessels in chronic heart failure. Requires a mandatory $36\text{-hour}$ washout period when switching from an ACE inhibitor to prevent severe angioedema. Elevates serum potassium.

Digoxin

A cardiac glycoside that inhibits Na+/K+ ATPase, causing a positive inotropic (stronger contraction) and negative chronotropic (slower rate) effect. Used in heart failure and atrial fibrillation. Toxicity presents as anorexia, nausea, vomiting, yellow-green halos around lights, and dysrhythmias. Risk is greatly increased by hypokalemia. Antidote is digoxin immune Fab (DigiFab).

Diuretic Sites of Action

Different diuretic classes act along the nephron: mannitol acts osmotically in the proximal tubule; furosemide acts powerfully in the thick ascending loop of Henle; hydrochlorothiazide acts moderately in the early distal tubule; and spironolactone acts weakly in the collecting duct. Furosemide and HCTZ lower potassium, while spironolactone raises it.

Furosemide

A high-ceiling loop diuretic that blocks Na+-K+-2Cl- transport in the loop of Henle, producing rapid and potent diuresis even with impaired renal function. Major dangers include severe hypokalemia, hyponatremia, dehydration, and ototoxicity (tinnitus, hearing loss) if administered via rapid IV injection.

Spironolactone

A potassium-sparing diuretic that competitively inhibits aldosterone in the distal renal tubules and collecting duct. Used for heart failure, hypertension, and ascites. Dangers include hyperkalemia and endocrine adverse effects such as gynecomastia in men and menstrual irregularities in women.

Mannitol

An IV osmotic diuretic that raises blood and filtrate osmolality, drawing water from intracellular spaces (such as the brain and eye) into the vascular space for urinary excretion. Used for elevated intracranial or intraocular pressure. Can trigger acute pulmonary edema and fluid overload; must be inspected for crystals and infused using an in-line filter.

Nitroglycerin

An organic nitrate that converts to nitric oxide, causing venodilation, decreased venous return (preload), and reduced myocardial oxygen demand. Used for acute angina. Expected side effects include throbbing headache and flushing. Absolutely contraindicated with PDE-5 inhibitors (sildenafil, tadalafil) due to catastrophic hypotension.

Ranolazine

An antianginal agent that reduces intracellular sodium and calcium accumulation by inhibiting late sodium current, improving myocardial metabolic efficiency without significantly lowering heart rate or blood pressure. Used for chronic stable angina only; prolongs the QT interval.

Atorvastatin

An HMG-CoA reductase inhibitor that reduces hepatic cholesterol synthesis and upregulates LDL receptors. Major adverse effects include hepatotoxicity (elevated LFTs) and rhabdomyolysis (muscle pain, weakness, dark cola-colored urine). Contraindicated in pregnancy and active liver disease; avoid grapefruit juice.

Ezetimibe

A cholesterol absorption inhibitor that selectively blocks dietary and biliary cholesterol absorption across the intestinal brush border. Lowers LDL and is often combined with a statin. Must be separated from bile-acid sequestrants by at least $2\text{ hours}$ before or $4\text{ hours}$ after.

Colesevelam

A bile-acid sequestrant that binds bile acids in the intestinal lumen, causing fecal excretion and forcing the liver to convert circulating cholesterol into new bile. Causes constipation and bloating, may elevate triglycerides, and can bind fat-soluble vitamins (A, D, E, K) and other medications unless spaced by $4\text{ hours}$.

Alirocumab

A PCSK9 inhibitor monoclonal antibody administered via subcutaneous injection that prevents the degradation of hepatic LDL receptors, dramatically lowering serum LDL levels in familial hypercholesterolemia or high-risk atherosclerotic disease.

Vaughn-Williams Antiarrhythmic Classification

A four-class antiarrhythmic system based on channel blockade: Class I blocks sodium channels (Ia quinidine, Ib lidocaine, Ic propafenone/flecainide); Class II blocks beta receptors (propranolol); Class III blocks potassium channels (amiodarone); and Class IV blocks calcium channels (verapamil, diltiazem). Adenosine and digoxin act on the AV node as other/Class V agents.

Quinidine

A Class Ia antiarrhythmic that moderately blocks sodium channels and delays repolarization, prolonging the QT interval. Used for atrial and ventricular dysrhythmias. Frequent adverse effects include severe diarrhea, cinchonism (tinnitus, headache, dizziness, blurry vision), and torsades de pointes. Increases digoxin levels.

Lidocaine (IV)

A Class Ib antiarrhythmic that selectively blocks sodium channels in ischemic ventricular myocardium to suppress life-threatening ventricular dysrhythmias (VT, VF). Manifestations of CNS toxicity include circumoral numbness, tongue tingling, tremors, confusion, slurred speech, and seizures.

Propafenone and Flecainide

Class Ic antiarrhythmics that exert powerful sodium channel blockade and markedly slow cardiac conduction, widening the QRS complex. Used for atrial fibrillation and SVT only in patients with structurally normal hearts; strictly contraindicated after myocardial infarction or in structural heart failure due to high risk of fatal proarrhythmia.

Amiodarone

A Class III antiarrhythmic that primarily blocks potassium channels to prolong cardiac repolarization, used for recurrent VF and pulseless VT. Contains iodine and accumulates in tissues for months. Causes severe organ toxicities: pulmonary fibrosis (new cough, dyspnea), thyroid dysfunction (hypo- or hyper-), liver damage, corneal deposits, and blue-gray skin discoloration.

Adenosine

An endogenous nucleoside (other/Class V) that momentarily halts electrical conduction through the AV node to convert paroxysmal supraventricular tachycardia (SVT) to normal sinus rhythm. Administered as a rapid IV push over $1\text{ to }2\text{ seconds}$ followed immediately by a rapid $20\text{ mL}$ saline flush; expected to cause a transient several-second asystolic pause.

Atropine

An anticholinergic (muscarinic receptor antagonist) that blocks vagal inhibition on the SA node, accelerating heart rate in symptomatic bradycardia. Side effects reflect cholinergic blockade: dry mouth, blurred vision, urinary retention, constipation, and reduced sweating ("can't see, can't pee, can't spit, can't poop").

Coagulation Cascade Target Steps

A schematic organizing hematologic drugs by their mechanism: clopidogrel blocks platelet clumping; rivaroxaban, fondaparinux, and enoxaparin inhibit factor Xa; dabigatran, argatroban, and heparin inhibit thrombin; and alteplase (tPA) dissolves the final fibrin clot.

Heparin (Unfractionated)

A parenteral anticoagulant that binds and accelerates antithrombin III, inactivating thrombin and factor Xa to prevent clot expansion. Monitored via aPTT (goal $1.5\text{ to }2.5\text{ times control}$) or anti-Xa. Life-threatening complication is heparin-induced thrombocytopenia (HIT; platelet drop $>50\%$ with paradoxical thrombosis). Specific antidote is protamine sulfate.

Enoxaparin

A low-molecular-weight heparin (LMWH) that primarily inhibits factor Xa. Given subcutaneously into the anterolateral/posterolateral abdominal wall ("love handles"); do not expel the manufactured air bubble or rub the site. Carries a boxed warning for spinal/epidural hematoma and paralysis. Protamine sulfate provides only partial reversal.

Fondaparinux

A synthetic pentasaccharide that selectively binds antithrombin to indirectly inhibit factor Xa. Does not cause heparin-induced thrombocytopenia (HIT). Contraindicated in severe renal impairment ($\text{CrCl}<30\text{ mL/min}$) or body weight $<50\text{ kg}$ for prophylaxis. Has no specific reversing antidote.

Warfarin

An oral vitamin K antagonist that blocks hepatic synthesis of clotting factors II, VII, IX, and X. Takes $3\text{ to }5\text{ days}$ to reach therapeutic effect; monitored via PT/INR (goal $2.0\text{ to }3.0$). Patients must maintain consistent dietary intake of leafy green vegetables containing vitamin K. Teratogenic in pregnancy. Antidote is vitamin K (phytonadione) and 4-factor PCC.

Dabigatran

An oral direct thrombin inhibitor used for stroke prevention in nonvalvular atrial fibrillation and DVT/PE. Capsules must be swallowed whole and stored strictly in their original moisture-protecting manufacturer container. Specific reversing antidote is idarucizumab (Praxbind).

Argatroban

An IV direct thrombin inhibitor indicated specifically for anticoagulation in patients with confirmed or suspected heparin-induced thrombocytopenia (HIT). Cleared hepatically (requires dose adjustment in liver disease) and monitored using aPTT. Has no reversing antidote.

Rivaroxaban

An oral direct factor Xa inhibitor used for stroke prevention in atrial fibrillation, DVT/PE treatment, and surgical VTE prophylaxis. The $15\text{ mg}$ and $20\text{ mg}$ doses must be taken with the evening meal to facilitate absorption. Reversing antidote is andexanet alfa.

Clopidogrel

An oral thienopyridine antiplatelet agent that irreversibly blocks P2Y12 ADP receptors on platelets for their $7\text{ to }10\text{ day}$ lifespan. Critical for maintaining coronary stent patency; abrupt discontinuation can cause fatal in-stent thrombosis. Avoid concurrent use with omeprazole, which reduces its activation.

Alteplase (tPA)

A thrombolytic agent that initiates fibrinolysis by converting plasminogen into plasmin, directly dissolving pre-existing pathological fibrin thrombi. Used in acute ischemic stroke ($3\text{ to }4.5\text{ hours}$ window), pulmonary embolism, and STEMI. Highest risk is intracranial hemorrhage; must rule out intracranial bleeding via CT scan before administration.

Hypocalcemia vs Hypercalcemia

Hypocalcemia ($<8.5\text{ mg/dL}$) causes heightened neuromuscular irritability presenting with circumoral and digital paresthesias, muscle spasms, twitching, and potential seizures ("twitchy + tingly"). Hypercalcemia ($>10.5\text{ mg/dL}$) depresses smooth muscle and neuronal activity, leading to generalized muscle weakness, constipation, polydipsia/polyuria, and kidney stones ("weak + constipated").