Pharmacology Flashcards
(58 cards)
1
Q
Carbonic anhydrase inhibitors
A
- acetazolamide; methazolamide; dichlorphenamide
- inhibits luminal CA at proximal tubule→ less activity of Na/H antiporter, decreased HCO3 and Na+ (and water) reabsorption
- FeNa=5%
- Contraindicated in cirrhosis
- Tx: glaucoma (decrease IOP and vol), mountain sickness
- side effects: hypokalemia, metabolic acidosis; hepatic encephalopathy, BM depression, skin toxicity, sulfonamide HSR
2
Q
Aminophylline
A
- PDE inhibition and enhanced signalling via cAMP and cGMP; works at proximal tubule; decreased HCO3 and Na (and water) reabsorption
- aminophylline = theophylline + ethyelenediamine (solubility agent)
- Tx: reduce inflammation and bronchospasm in moderate-severe asthma, night symptoms; NOT as diuretic
- FeNa = 5%
- side effects: larger doses→ N/V CNS stimulation or seizures, tachycardia/arrythmias
- metabolized by liver; cimetidine and quinoline increase blood levels
3
Q
Mannitol
A
- osmotic diuretic; opposes H2O and Na reabsorption at proximal tubule→ increased osmolarity of tubular fluid
- Tx: increased drug clearance, minimize renal failure (shock or surgery), decrease IOP/ICP, diagnose oliguria
- FeNa = 5%
- side effects: risk of pulmonary edema
4
Q
Loop diuretics
A
- furosemide, bumetanide, torsemide, ethacrynic acid
- inhibits Cl portion of Na-K-2Cl cotransporter in luminal membrane at medullary and cortical (proximal) talH→ decreased K, Ca and Na reabsorption, resultant K loss
- Tx: crisis edema (pulmonary, CHF, cirrhosis), hypercalcemia, drug toxicity/OD; severe HTN in CHF or cirrhosis (vasodilate via prostaglandins and decrease preload by lowering volume)
- FeNa = 25%; eventually causes increase in PT reabsorption, decreases positive & negative free water clearance; decreases cortex-medulla molarity gradient; avoid NSAIDs, take before salty meals, reduce salt intake; useful in patients with renal insufficiency (GFR < 30)
- side effects: hyper glycemia/ lipidemia (DM!), hyperuricemia (gout!), hyperCa; hypoMg/K; photosensitivity, nephrocalcinosis, Rx interactions; ED
5
Q
Thiazide/thiazide-like diuretics
A
- thiazides: chlorothizide, hydrochlorothiazide
- thiazide-like: chlorthalidone, quinethazone, metolazone, indapamide
- inhibit Cl portion of Na-Cl cotransporter in the luminal membrane at early distal tubule→ decreased Na (and H2O) reabsorption, increased Ca reabsorption, resultant K loss
- Tx: HTN (intravascular contraction), CHF, chronic edema (cardiac insufficiency), idiopathic hypercalciuria (stones), nephrogenic diabetes insipidus
- FeNa = 8%
- side effects: hypoK/hyperCa, contraction alkalosis, decreases positive free water clearance; increased BUN & creatinine; hyperglycemia/lipidemia (DM) hyperuricemia (gout); hypo magnesia /natremia; gout, photosensitivity, ED
- lethal interaction w/quinidine (v. tach→ fib, may be due to hyperK)
- avoid NSAIDs, bile sequestrants
- increased risk of hypoK w/steroids or AmphoB
6
Q
K+ sparing diuretics
A
- amiloride, triamterene
- work on principal cell of collecting duct to blocks ENaC and Na/H antiporter in lumenal membrane→ decreased K secretion and distal tubule acid secretion, increased Ca absorption
- FeNa = 2%
- Tx: use w/ other diuretics to prevent hypokalemia; edema, idiopathic hypercalciuria (stones); Li-induced polyuria/toxicity, Liddle syndrome, mucocilliary clearance
- side effects: hyperkalemia in renal failure or patients on ACEi/ARBs
7
Q
Aquaretics
A
- conivaptan, tolvaptan
- new drug class with unproven clinical benefit
- ADH receptor antagonist working at collecting duct→ increased free water excretion
- Tx: hyponatremia (SIADH, CHF)
8
Q
Eplerenone
A
- K+ sparing diuretic; selective aldosterone receptor blocker devoid of antiandrogenic effect (inhibits Na reabsorption in distal tubule)
- Tx: CHF (30% in NYHA class III and IV); use w/ other diuretics to prevent hypoK; HTN edema; 1’/2’ aldosteronism; anti-testosterone agent
- side effects: hyperK; low incidence of gynecomastia and mennorhagia vs. spironolactone
9
Q
Spironolactone
A
- K sparing diuretic; competes for aldosterone receptor, inhibiting mRNA transcription and translation→ decreased Na and K channels, decreased #/activity of Na-K-ATPase in late distal tubule and collecting duct→ decreased K+ secretion, distal tubule acid secretion
- Tx: CHF mortality (30% in NYHA class III and IV); use w/ other diuretics to prevent hypokalemia; HTN edema; 1’/2’ aldosteronism; anti-testosterone agent
- side effects: hyperK in renal failure or patients on ACEi; gynecomastia, ED, a/oligomenorrhea, breast soreness
10
Q
ACE inhibitors
A
- short acting: capto_pril_
- long acting: lisinopril, benazepril, quinapril, ramipril**
- vasodilating: enalapril**
- blocks ACE conversion of ATI to ATII (potent vasoconstrictor); prevents breakdown of bradykinin (potent vasodilator)
- Tx: 1st line for CHF (reduces afterload), LV hypertrophy, post-MI (prevents LV remodeling); protective of diabetic nephropathy; mild/ moderate HTN, reduces incidence of future CAD events in at risk for or PMH of vascular disease;
- side effects: dry cough, hyperK, angioedema, inhibits renal autoregulation, hypotension
- contraindicated in pregnancy, renal artery stenosis, hyperK, and prior angioedema; caution in ARF; reduces future CAD events; may reduce risk of DM
11
Q
ARBs
A
- losartan, valsartan, irbesartan**
- competitive inhibition of ATII in vascular endothelium→ fall in PVR w/ little change in HR or CO
- Tx: CHF (reduces afterload), LV hypertrophy, post-MI (prevents LV remodeling); protective of diabetic nephropathy; mild/ moderate HTN
- as effective as ACEi; use if cough is an issue
- side effects: angioedema, decreased renal function, hypotension;
- contraindicated in pregnancy, renal artery stenosis, hyperkalemia, and prior angioedema; caution in ARF
12
Q
Aliskiren
A
- renin inhibitor (blocks ATI formation)
- not v. effective
- does not interfere with bradykinin
13
Q
Non-dihydropyridine Ca channel blockers
A
- diltiazem; verapamil (most heart specific)
- blocks L-type Ca channel→ decreased Ca intracellularly→ decreases CO (lowers HR via decrease AV nodal conduction) and decreases TPR (less than dihydropyridine)
- Tx: HTN, angina (esp. vasospastic; - ionotrope→ decreased MO2 demand), SVT (class IV anti-arrhythymic); good to preserve renal function in DM and CKD
- side effects: leg edema, bradycardia, AV nodal blockade, hypotension, worsening HF; constipation (most common), headache, flushing
- contraindicated in overt decompensated HF, bradycardia, sinus node dysfunction, high-degree AV block
14
Q
Dihydropyridine Ca channel blockers
A
- nifedipine, amlodipine**
- L-type Ca channel→ decreased Ca in vascular SM→ decreases TPR; no effect on AV nodal conduction
- Tx: HTN, Raynauds, angina (3rd choice drug); 1st line for coronary vasospasm;
- side effects: leg edema (less than nondihydros), constipation (most common), headache, flushing
- no bradycardia, can use in low HR patients, can use in patients with AV block
15
Q
ß blockers for HTN
A
- lower CO and decrease renin release
- Tx: 1st line for HTN if CHF, post MI/angina, CAD
-
nonselective: propranolol
- bronchospasm, bradycardia (-chronotrope), CHF (- ionotrope), masking hypoglycemia
- decreased exercise capacity, depression (crosses BBB), worsening PVD
-
selective ß1: metoprolol, atenolol, esmolol
- decrease contractility and HR (reduced MO2 demand); prevent MIs, prevent sudden cardiac death, increase survival post-MI (do not stop suddenly)
- less likely to have bronchospasm, hypoglycemic awareness, and depression
- side effects: fatigue, worsening claudication, impotence
-
combined a/ß: labetolol, carvedilol
- ß1 blockage with vasodilatory effects
- Tx: HTN urgency, ACS, CHF
16
Q
Terazosin (Hytrin)
Doxazosin (Cardura)
A
- blocks post-synaptic a1 receptor on vascular SM→ decreased arteriolar and venous resistance
- Tx: BPH (decrease tone of urinary sphincter), 2nd tier med for HTN
- side effects: orthostatic hypotension, fluid retention, worsening angina (2nd to reflex tachy)
17
Q
Clonidine (Catapres)
α-methyldopa (Aldomet)
A
- central α2-agonist→ reduction in symp outflow; inhibition of renin release (2nd to decreased symp tone)
- a methyldopa: only drug for HTN of pregnancy; takes place of dopa, so less NE (methyl-NE also activates α2)
- side effect: rebound HTN if abruptly stopped; moderate orthostatic hypotension; sedation, dry mouth, fatigue, depression
18
Q
Reserpine (Serpalan)
A
- ganglion blocking agent (blocks transport of NE, DA, and 5HIAA vesicles)
- Tx: decreased CO and TPR
- side effects: sedation, depression, Parkinsonism symptoms
19
Q
Hydralazine (Apresoline)
A
- direct vasodilators (prevent oxidation of NO)→ decrease TPR via arteriolar dilation
- Tx: HTN urgency; patients with both CHF and HTN
- side effects: SLE-like syndrome; reflex tachy
20
Q
Minoxidil (Loniten)
A
- direct vasodilators; open K channels→ hyperpolarization of SM→ vasodilation of arterioles
- Tx: refractory HTN; hair loss
- side effects: leg edema, pericardial effusion; hirsutism; reflex tachy
21
Q
Niacin (Niaspan)
A
- nicotinic acid→ reduction of liver TG synthesis→ less hepatic VLDL (thus LDL); decreases lipolysis in adipose→ lowered FFA transport to liver (thus, less TGs); reduced hepatic clearance of ApoAI (raising HDL)
- best agent to increase HDL (30-40%); as good as fibrates and statins at lowering TGs (35-4%); lowers LDL (20-30%)
- Tx: hyperTG and low HDL
- side effects limit compliance (<50%): flushing, pruritis of face and upper trunk (take aspirin), rashes, acanthosis nigricans, hepatotoxicity, hyperuricemia, hyperglycemia; dyspepsia/reactivation of peptic ulcer disease; rarely, toxic ambylopia, tachyarrhythmias, a-fib (in elderly) and myopathy
- contraindicated in DM and gout patients
22
Q
Fibric Acid Derivatives (Fibrates)
A
- Clofibrate, gemfibrozil, fenofibrate
- may interact w/peroxisome proliferator-activated receptor (esp. PPARα) to induce LPL (enhance TG-rich lipoprotein clearance); inhibit apoC III expression (enhance VLDL clearance); stimulation of apoAI and apoAII (increase HDL)
- Marked reduction in VLDL (thus, TGs); variable small effect on LDL; small increase in HDL (10%)
- Tx: severe hyperTG
- side effects: potentiate oral anticoag (displace from albumin), gallstones; myositis flu-like syndrome in 5% (higher risk + statin)
23
Q
Bile acid sequestrants
A
- colestipol, cholestyramine, colesevelam
- v. + resins bind - bile acids, inhibiting reabsorption and increasing CH loss→ increase LDL receptors in liver (to make more CH), decreasing LDL in blood
- Tx: pure hyperCH (decrease LDL (25%), but slight increase (5%) in TG and HDL)
- v. safe (indicated for kids) because not systematically absorbed; impairs vitamin ADKE absorption, binds other drugs (e.g., cardiac glycosides, coumarins)
- standard treatment in combo w/statin; contraindicated in hyperTG
- side effects: bloating, dyspepsia, constipation, gritty/unpleasant taste
24
Q
HMG-CoA reductase Inhibitors (statins)
A
- lovastatin, simvastatin: lactone product (modified in liver to hydroxy acid form), take in pm
- pravastatin, fluvastatin: take in pm
- atorvastatin, rosuvastatin, pitavastatin: longer t1/2
- inhibits HMG-CoA reductase formation of mevalonate; activates SREBP, membrane-bound TF that increases LDL-R synthesis and lessens degradation
- Tx: 1st line for dyslipidemia (reduces fatal & nonfatal CHD, strokes; total mortality reduction is 20%)
- reduce LDL (20-55%) and TG (25%), while increasing HDL (5-10%)
- side effects: hepatic dysfunction in 1%; myopathy/ rhabdo (reduced if factors inhibiting statin catabolism lacking)
25
Ezetimbe (Zetia)
* inhibits enterocyte absorption of CH in jejunum→ decreased LDL alone (15-20%) or w/statin (60%)
* side effect: GI distress
* LT decrease in endpoints not seen yet (questionable effectiveness)
26
Alirocumab
Evolucumab
* inhibits an endopeptidase (PCSK9) responsible for LDL-R degradation→ higher # LDL-Rs on hepatocytes
* **Tx: 2nd line for hyperCH not controlled by diet and statins**
* side effects: injection site rxns; flu-like symptoms; nose and throat irritation; muscle pain; diarrhea
27
Aspirin
* NSAID; irreversible COX inhibitor (o TxA2 synthesis), so **blocks platelet aggregation**
* Tx: reduce adverse events (MI, CVA, death); stable angina, unstable angina, acute MI, prophylaxis
* Low-doses; if you're allergic, you'll get asthma
28
Ticlopidine (Ticlid)
* Thienopyridine antiplatelet agent; inhibits platelet aggregation by ADP; reduces blood viscosity by decreasing plasma fibrinogen and increasing RBC deformability
* use as an aspirin alternative **(not really used anymore)**
* side effects: **neutropenia,** TTP (rarely)
29
Clopidogrel (Plavix)
* Thienopyridine antiplatelet agent; selectively and irreversibly inhibits ADP binding to P2Y12 (blocks ADP-dependent activation of GP IIb/IIIa complex)
* Tx: great antithrombotic; **standard of care w/ stent**
* side effect: bleeding (no surgical or dental procedures)
30
Prasugrel (Effient)
* Thienopyridine antiplatelet agent; irreversibly binds P2Y12 receptor (GCRP chemoreceptor for ADP)
* Tx: reduce thrombotic events in those w/ stent
* **massive bleeding risk (1:1 save from MI die from bleeding event); use** limited to patients \<75 yo, \>60kg and no history of stroke or TIA
31
Ticagrelor (Brilinta)
* Adenosine-like antiplatelet agent; reversibly blocks ADP receptors
* Tx: great antithrombic
* side effect: bleeding (be careful about aspirin use in addition)
* requires bid dosing
32
Dipyradimole (Persantine)
* Pyrimido-pyrimidine antiplatelet agent; increases platelet intracellular cAMP (inhibits PDE 5, activates adenylate cyclase, inhibits uptake of adenosine from vascular endothelium and RBCs)
* **Tx: PVD (as adjunct); chemical stress test**
* side effects: **vasodilation of coronary arteries can enhance exercise-induced ischemia** (elevates extracellular adenosine)
* **do not use in patients with CAD**
33
Cilostazol (Pletal)
* Quinoline antiplatelet agent; inhibits cellular PDE→ raises intracellular cAMP
* Tx: claudication with PVD (3rd line)
* side effects: vasodilation
* contraindicated in HF
34
Nitrates
* **Isosorbide ditrate, isosorbide mononitrate**
* vasodilator; functions as NO in SM: vasodilation, venodilation (decrease preload, decrease MO2), decrease infarct size and improves MI mortality
* Tx: **acute episodes; long-acting** for those on other drugs and still can't control angina
* side effects: **tolerance w/chronic use** (need nitrate free periods of 8-12 hrs), **headaches,** hypotension, activation of Bezold-Jarisch reflex (causes brady); decreases preload
* Contraindicated in hypertrophic cardiomyopathy, severe aortic stenosis, significant hypotension, use of PDE inhibitors
35
Digoxin
* Cardiac glycoside and anti-arrhythmic
* inhibits Na/K ATPase (more Ca→ increase contractility); indirect increase vagal and sympathetic activity (decrease HR, NE, RAAS)
* Tx: **CHF (no mortality benefit); SVTs;** improves LV function, decreases neurohormonal activation, increases vagal tone, normalizes arterial baroreceptors; decreases hospitalizations in a-fib/flutter
* side effects: nausea, cognitive dysfunction, blurred or yellow vision; DAD arrythmias
* **v. narrow TI** (mostly arrhythmias); Fab antibodies for toxicity
* renal elimination (dose according to renal function)
36
Dobutamine (Dobutrex)
* β1 receptor agonist; + inotrope and chronotrope
* Tx: **acutely decompensated patients (50% will die after 6 mo)**
* side effects: **quick acting, but can develop tachyphylaxis after 48 hrs (rapidly desensitizes)**
* No NE release; given IV
37
Milrinone (Primacor)
* PDE IIIa inhibitor; inhibits cAMP breakdown→ increase Ca (+inotrope, vasodilation and decrease TPR in SM)
* Tx: **acute setting of HF (short-term only)**
* increased hypotensive and atrial arrhythmia events acutely; 2 mo mortality \>50% higher vs. placebo
* IV, depends on renal clearance, no tolerance after 72 hrs
38
Bronchodilator (short-acting β2 agonist)
* **al**_but_**erol, ter**_but_**aline, metoproterenol, pir**_but_**al**
* Relax bronchial SM, inhibit mediator release (mast cells, basophils), increase mucociliary clearance, suppression of microvascular permeability
* Tx: **prevent/reduce exercise-induced bronchospasms; mild asthma & acute exacerbations**
* side effects: msk tremor, tachy, hyperglycemia, hypokalemia, hypomagnesemia
* tolerance with chronic use, prolonged QTc, lactic acidosis, paradoxical bronchospasm
* 5 mins to take action, 4-6 hrs duration; nebulizer delivers more, but greater side effects
39
Bronchodilator (long-acting β2 agonist)
* salme_terol,_ formo**_terol_**, indaca**_terol_**
* Relax bronchial SM, inhibit mediator release (mast cells, basophils), increase mucociliary clearance, suppression of microvascular permeability
* Tx: **LT control of asthma (always in combo with inhaled steroids)**
* side effects: msk tremor, tachy, hyperglycemia, hypokalemia, hypomagnesemia
* tolerance with chronic use, prolonged QTc, lactic acidosis, paradoxical bronchospasm
* 10-15 mins to act, 6-12 hrs duration; nebulizer delivers more, but greater side effects; oral is least effective (requires more dose→ side effects); not ideal for pm symptoms
40
Theophylline (Theolair)
Theobromine
Caffeine
* Bronchodilator (Methylxanthine); PDE inhibition and enhanced signalling via increased cAMP and cGMP; relax bronchial SM
* Tx: reduce inflammation and bronchospasm in moderate-severe asthma, pm symptoms
* side effects: CNS stimulation or seizures, tachy/arrythmias, anorexia, nausea
* low TI; metabolized by liver; cimetidine and quinoline increase blood levels
41
Roflumilast
* Methylxanthine; selective PDE4 inhibitor; more anti-inflam than bronchodilator
* Tx: COPD
* side effects: CNS stimulation or seizures, tachy/arrythmias, anorexia, nausea
42
Ipra**_tropium_** (Atrovent)
Tio**_tropium_**
A**_tro_**pine
* 4' amine antimuscarinic; blocks vagal pathways and decreases vagal tone to bronchial SM; blocks the reflex bronchoconstriction caused by inhaled irritants
* **Tx: 1st line for COPD; status asthmaticus (w/ nebulized β2-agonists); no role in chronic stable asthma**
* side effects: Typical antimuscarinic effects; acute angle glaucoma; paradoxical bronchospasm
* **tiotropium:** anti-inflam and decreases mucus
43
Aclidinium Bromide
* 4' amine antimuscarinic; blocks vagal pathways and decreases vagal tone to bronchial SM; blocks the reflex bronchoconstriction caused by inhaled irritants
* Tx: COPD; status asthmaticus (w/ nebulized β2-agonists); no role in chronic stable asthma
* side effects: **less systemic & CNS side effects than other antimuscarinics** due to extremely short circulation half-life
44
Budesonide
Fluticasone propionate
Beclomethasone
* corticosteroid; anti-inflammatory, inhibition of growth factor secretion, inhibition of arachidonic acid metabolites and platelet activation factor, inhibition of leukocyte accumulation, decreased vascular permeability, inhibition of neuropeptide-mediated responses, inhibition of mucous glycoprotein secretion
* Tx: **cornerstone for persistent asthma;** beneficial combo w/ ß2 agonist; limited role in COPD
* side effects
* inhaled: thrush, hoarseness, dry cough, mild adrenal suppression (higher doses)
* oral: mood-swings, increased appetite, and suppression of ACTH (Cushing's)
45
Ciclesonide
* corticosteroid; anti-inflam with same mechanism as other corticosteroids, but is a **prodrug only activated by airway esterase**
* Tx: **cornerstone for persistent asthma;** beneficial combo w/ ß2 agonist; limited role in COPD
* Less side effects than other corticosteroids (on site activation required)
46
Sodium cromoglycate
Nedocromil sodium
* Anti-inflam; prevent mast cell degranulation and mediator release from mast cells
* Tx: prophylaxis for inhibiting early and late phase rxns; **best results in mild and allergic asthma**
* side effect: cough, throat irritation
47
Montelukast
Pranlukast
Zafirlukast
* Leukotriene receptor antagonist
* Tx: add-on in mild persistent asthma; aspirin-induced asthma; prophylaxis for exercise-induced bronchospasm
* monitor LFTs
48
Zileuton (Zyflo)
* Leukotriene inhibitor; inhibits 5-lipoxygenase and blocks leukotriene synthesis
* Tx: add-on in mild persistent asthma; aspirin-induced asthma; prophylaxis for exercise-induced bronchospasm
* side effects: liver toxicity
49
Omalizumab
anti IgE for poorly controlled severe asthma; subQ injection every 3 wks
50
Class IA anti-arrhythmics
* **Quinidine, procainamide, disopyramide**
* **Block fast Na preferentially in open/activated state; increase APD and ERP, decrease slope of phase 0;** block K rectifying channel (prolongs repolarization)
* Tx: a-fib/flutter, paroxsymal SVT, v-tach
* side effects: **long QT; TdP arrhythmias**; heart block; hypotension; lupus-like syndrome (procainamide); GI symptoms; cinchonism (quinidine), hepatitis, thrombocytopenia (quinidine); anticholinergic effects (disopyramide)
51
Class IB anti-arrhythmics
* **lidocaine, mexiletine**
* **Block fast Na channels in inactivated state (prevent return back to resting and firing new AP); decrease APD; slow conduction in hypoxic and eschemic heart**
* **Tx: post MI; open heart surgery; digitalis toxicity**
* side effects: tremor, nausea, seizures, local anesthetic action; GI toxicity w/ mexiletine
52
Class IC anti-arrhythmics
* **flecainide, propafenone, moricizine**
* **most potent class I Na channel blockers (esp. His-Purkinje);** no effect on APD, acts as negative ionotrope
* Tx: a-fib/flutter, paroxsymal SVT, v-tach
* side effects: worsened HF, proarrhythmia in ischemic tissue, increased mortality; blurred vision w/ flecainide; sinus brady and brochospasm w/ propafenone
53
Class II anti-arrhythmics (non selective ßblockers)
* **propanolol, carvedilol**
* **decrease SA, AV node activity, decrease slope phase 4**
* Tx: **SVTs;** control of ventricular rate in a-fib/flutter
* side effects: heart block, hypotension, brochospasm, bradycardia; contraindicated in WPW
* decreases mortality in CHF
54
Class II anti-arrhythmics (selective ßblockers)
* **metoprolol, acebutolol, esmolol**
* **Blocks ßreceptors; decrease SA, AV node activity (phase 4 depolarization)**
* Tx: post MI prophylaxis (- inotropy decreases MO2 demand) control ventricular rate in a-fib/flutter, LT suppression of SVTs, PVCs
* side effects: heart block, hypotension, brochospasm, bradycardia; contraindicated in WPW
* decreases mortality in CHF
55
Class III anti-arrhythmics
* **sotalol, amiodarone, dofetilide, ibutelide, dronedarone**
* **K channel blockade = prolongs refractoriness (increase APD and ERP; slows phase 3)**
* **Tx: a-fib**/flutter, paroxsymal SVT, v-tach
* **amiodarone:** mimics all antiarrythmics; **use for any arrythmia, 1st line for sustain VT/VF;** long t1/2
* **sotalol:** treats life-threatening ventricular arrythmia
* side effects: TdP; long QT, bradycardia; pulmonary fibrosis, peripheral neuropathy, hepatic dysfunction, hypotension, brochospasm
* Photosensitivity (blue-gray skin; numerous drug interactions; N & V w/ dronedarone
56
Class IV anti-arrhythmics (Ca channel blockers)
* **nifedipine, amlodipine, verapamil, diltiazam**
* **Block L-type Ca channels (slow SA & AV node activity); decrease phase 0 and phase 4**
* **Tx: prevent or terminate reentrant SVTs**
* side effects: AV block; hypotension, bradycardia, constipation, dizziness; increases serum digoxin levels; contraindicated in WPW
57
Adenosine
* anti-arrhythmic; adenosine receptors in atrium, sinus node, AV node; activates K current, shortening AP, hyperpolarizing tissue, and slowing down automaticity and AV conduction
* Tx: a-fib, paroxsymal SVT
* side effects: sedation, dyspnea, hypotension
58
Magnesium sulfate
* Anti-arrhythmic
* Tx: prevents recurrent TdP and some digitalis-induced arrhythmias
* **alternative to amiodarone for shock-refractory cardiac arrest**
