Propranolol is also frequently combined with nitrates to combat nitrate-induced reflex tachycardia

FIGURE 70 Propranolol is also frequently combined with nitrates to combat nitrate-induced reflex tachycardia. 

The nitrates and nitrites are best absorbed through the mucous membrane lining the mouth and nose. Therefore, they are usually administered sublingually or buccally. They may also be inhaled. When administered by these routes, the active ingredient is absorbed into the venous circulation and travels via the vena cava to the heart, aorta, and coronary arteries. If these agents are taken orally, they are metabolized to inactive compounds by nitrate reductase in the liver. 

Calcium-entry blockers include those agents that are selective for slow calcium channels in the myocardium (slow-channel blockers), and consist of the following categories of substances  

Phenylalkylamines— verapamil, gallopamil, anipamil, desmethoxyverapamil, emopamil, fahpamil, and ronipamil 

Dihydropyridines— nifedipine, nicardipine, nilu-dipine, nimodipine, nisoldipine, nitrendipine, ryo-sidine, amlodipine, azodipine, dazodipine, felo-dipine, flordipine, iodipine, isradipine, mesndipine, oxodipine, and riodipine 

---