Chapter 1-05: Key Medications and Interventions in Cardiology

Diuretics

See Nephrology Chapter 6

Calcium channel blockers (CCB)

Dihydropyridine:

• amlodipine

• clevidipine

• nicardipine

• nifedipine

• nimodipine

Block voltage-dependent L-type Ca²⁺ channels → muscle contractility; acts on vascular smooth muscle

• Hypertension

• Angina [including Prinzmetal)

• Raynaud’s

• Nimodipine: Prophylaxis against vasospasm in SAH

• Peripheral edema

• Flushing

• Dizziness

Non-DHP:

• diltiazem

• verapamil

Block voltage-dependent L-type Ca²⁺ channels → muscle contractility; acts on heart

• Hypertension

• Angina

• Afib/flutter

• Cardiac depression

• AV block

• Hyperprolactinemia

• Constipation

• Gingival hyperplasia

ACE-inhibitors (ACEi)

• Captopril

• enalapril

• lisinopril

• ramipril

Inhibition of ACE lowers angiotensin II, with reduction in GFR due to relaxation of efferent arteriole; prevents inactivation of bradykinin (i.e., a vasodilator)

• Hypertension

• Heart failure

• LV hypertrophy

• Diabetic nephropathy

• Cough

• Hyperkalemia

• Angioedema

• Teratogen (contraindicated in pregnancy)

Angiotensin receptor blockers (ARB)

• Losartan

• candesartan

• valsartan

Blocks binding of angiotensin II; does not increase bradykinin levels

• Same as ACEi above

• Often used second line if the patient develops cough with ACEi

• As with ACE inhibitor, but cough/angioedema much more rare

Vasodilator

• hydralazine

Relaxes smooth muscle via cGMP; arteriole dilatation > venodilation

• Acute severe hypertension

• Combination therapy with organic nitrates for hypertension

• Compensatory tachycardia (contraindicated in CAD)

• Headache

• SLE-like syndrome

Nitrodilators

• nitroprusside

Vasodilation via direct action; arteriole dilatation > venodilation

• Hypertensive emergency

• ADHF (afterload reduction)

• Cyanide toxicity

• Careful in renal failure

Organic nitrates:

• nitroglycerin

• isosorbide dinitrate

• isosorbide mononitrate

Vasodilation via increased nitrous oxide; venodilation >> arteriole dilatation

• Angina

• ACS

• Contraindication: Right ventricular MI

• Reflex tachycardia, hypotension

• Flushing, headache

Ranolazine

–

Inhibits late phase Na⁺ current particularly in ischemic cardiomyocytes; thereby decreases wall tension and O₂ consumption

• Refractory angina

• Dizziness, headache

• Nausea

• QT prolongation

Milrinone

–

Selective PDE-3 inhibitor; increases inotropy/chronotropy via Ca²⁺ influx to cardiomyocytes; also relaxes vascular smooth muscle

• Acute, decompensated HF

• Hypotension

• Arrhythmia

Glycosides

Digoxin

Inhibits Na⁺/K⁺ ATPase, which indirectly inhibits Na⁺/Ca²⁺ exchanger, resulting in increased inotropy; also slows HR via vagal nerve stimulation

• Heart failure

• Afib

• Cholinergic effects

• Hyperkalemia

• Toxicity, particularly in renal failure

Class I antiarrhythmic (Na⁺ channel blockers)

A: quinidine procainamide disopyramide

B: lidocaine mexiletine

C: flecainide propafenone

Slows or blocks phase 0 conduction, particularly for depolarized cells

A: Atrial/ventricular arrhythmia

B: Post-MI ventricular arrhythmia, digitalis-induced arrhythmia

C: SVT, including Afib

A: QT prolongation, SLE-like syndrome (procainamide)

B: CNS effects

C: Proarrhythmic, particularly post-MI

Class II antiar-rhythmic (β blockers)

• Metoprolol

• propranolol

• esmolol

• atenolol

• timolol

• carvedilol

Decreases SA <AV nodal activity; decreases slope 4 of abnormal pacemaker cells

• Rate control for Afib/flutter or other SVTs

• Bradycardia

• Masked signs of hypoglycemia

• Impotence

• Dyslipidemia (metoprolol)

Class III antiar-rhythmic (K⁺ channel blockers)

• amiodarone (I-IV)

• ibutilide

• dofetilide

• sotalol

Increased duration of action potential/effective refractory period

• Afib/flutter

• VT (amiodarone, sotalol)

• Prolong QT

• Amiodarone: pulmonary, hepatic, and thyroid toxicity

Class IV anti-arrhythmic (Ca²⁺ channel blockers)

• Verapamil

• diltiazem

Decrease conduction velocity and increase effective refractory period

• Rate control in Afib, SVTs conducted ...