Cardiovascular Drugs Our Patients Take
Course Number: 581
Course Contents
Drugs that Regulate Vascular Tone
Vascular tone is another key determinant of tissue perfusion. Vascular smooth muscle cells are the functional regulatory units that integrate a variety of signals initiated by (1) local factors (e.g., H+, CO2, stretch), (2) endothelium-derived signaling molecules (e.g., nitric oxide, prostacyclin), (3) neurotransmitters (e.g., epinephrine), and (4) hormones (e.g., vasopressin) to optimize vascular tone.5 Ultimately, vascular smooth muscle tone is determined by the intracellular Ca2+ ion concentration.
Drugs in the top 300 that regulate vascular tone (Table 3) include (1) Ca2+ channel blockers, (2) β1-adrenoceptor antagonists, (3) α1-adrenoceptor antagonists, (4) α2-adrenoceptor agonists, (5) K+ channel openers, (6) nitric oxide donors, and (7) late sodium current blockers.2,5,6,10 These drug categories are intended for the management of systemic and pulmonary hypertension, ischemic heart disease (i.e., chronic coronary artery disease and acute coronary syndromes), and congestive heart failure5,6
Table 3. Drugs that Regulate Vascular Tone.2,5,6,10
| Drugs (Rank/300) | Mechanisms of Action | Common Indications |
|---|---|---|
| Calcium channel blockers • Amlodipine (5) • Diltiazem (76) • Nifedipine (135) • Verapamil (151) | Block voltage-gated L-type Ca2+ channels and thereby cause • Vasodilation • Depressed cardiac contractility • Depressed SA-node automaticity • Depressed AV-node conduction velocity | • Hypertension • Stable angina pectoris • Vasospastic angina • Unstable angina pectoris |
| β1-adrenoceptor antagonists • Metoprolol (6) • Carvedilol (26) • Atenolol (53) • Propranolol (88) • Labetalol (210) • Nebivolol (239) • Bisoprolol (267) | Block β1-adrenoceptors • Propranolol and nadolol also block β2-adrenoceptors • Labetalol and carvedilol also block β2- and α1-adrenoceptors | • Hypertension • Angina pectoris • Post-MI syndrome • Heart failure |
| α1-adrenoceptor antagonists • Prazosin (190) • Doxazosin (209) • Terazosin (211) | Block the binding of catecholamines to α1-adrenoceptors | • Benign prostatic hypertrophy • Hypertension |
| α2-adrenoceptor agonists • Clonidine (75) • Guanfacine (300) | Selectively activate central α2-adrenoceptors and thereby inhibit sympathetic outflow from the CNS | • Hypertension |
| K+ channel openers • Hydralazine | Open K+ channels in the plasma membrane of vascular smooth muscles thereby preventing the opening of Ca2+ channels causing arterial vasodilation | • Hypertension |
| Nitric oxide donors • Isosorbide (114) • Nitroglycerin (165) • Isosorbide dinitrate (299) | Release NO, which activates guanylyl cyclase and increases dephosphorylation of myosin light chain in vascular smooth muscle causing vasodilation | • Acute angina pectoris (nitroglycerin) • Prophylaxis for angina pectoris due to ischemic heart disease (isosorbide and isosorbide dinitrate) |
| Late sodium current blocker • Ranolazine (258) | Inhibits late inward Na current in myocardium, decreasing Na+ and Ca2+ overload, resulting in less diastolic stiffness | • Chronic angina pectoris |