Calcium channel antagonist conditions

Natale and Quincy used a Hantzsch approach to prepare 4-(4-isoxazyl)-l,4-dihydropyridines to study their potential as calcium channel antagonists. Treatment of aldehydes 202, 204 and 206, prepared by oxidation of the readily available alcohol, with two equivalents of ethyl acetoaeetate 8 in ammonium hydroxide and refluxing ethanol overnight gave the corresponding symmetrical dihydropyridine derivatives 203, 205, and 207 in modest yields. Notably, the more activated, electron withdrawing aldehyde performed better under the reported reaction conditions. 

Many different drug classes have shown to cause hypotension and orthostatic reactions and drugs for cardiovascular conditions, psychoactive medicines and polypharmacy, can all have this side effect (Box 5.15). Among the most frequently used drugs in the elderly are diuretics, ACE-inhibitors, angiotensin II antagonists, calcium channel blockers and antidepressants. 

In addition to angina, calcium channel blockers have well-documented efficacy in hypertension (see Chapter 11) and supraventricular tachyarrhythmias (see Chapter 14). They also show moderate efficacy in a variety of other conditions, including hypertrophic cardiomyopathy, migraine, and Raynaud s phenomenon. Nifedipine has some efficacy in preterm labor but is more toxic and not as effective as atosiban, an investigational oxytocin antagonist (see Chapter 17). 

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