Alpha, blocking drugs

A. Classification Subdivisions of the alpha-blockers are based on the presence or absence of selective affinity for Uj versus o. receptors. Other features used to classify the alpha-blocking drugs are their reversibility and duration of action. 

E) Sleep disturbances from alpha-blocking drugs... 

There appear to be no published reports of adverse interactions between intracavemous alprostadil (prostaglandin E,) and other drugs used for erectile dysfunction, but some manufacturers say that smooth muscle re-laxants such as papaverine and other drugs used to induce erections such as alpha-blocking drugs [e.g. intracavernosal phentolamine] should not be used concurrently because of the risks of priapism (painful prolonged abnormal erection). ... 

Drug-drug interactions Theuseofphospho-diesterase-5 inhibitors with concomitant medications has been reviewed from literature published in 1998-2007 [30 ]. Concomitant use of nitrates is completely contraindicated, and the authors suggested that precautions be taken with concomitant use of either alpha-blocking drugs or potent inhibitors of CYP3A. 

CLINICAL PHARMACOLOGY OF THE ALPHA-RECEPTOR-BLOCKING DRUGS Pheoch romocytoma... 

Alpha-receptor-blocking drugs do not seem to be effective in the treatment of peripheral vascular occlusive disease characterized by morphologic changes that limit flow in the vessels. Occasionally, individuals with Raynaud s phenomenon and other conditions involving excessive reversible vasospasm in the peripheral circulation do benefit from prazosin or phenoxybenzamine, although calcium channel blockers may be preferable for most patients. 

A group of drugs known collectively as ergot derivatives display some alpha-blocking ability as well as other unique properties. Ergot alkaloids and ergoloid mesylates and are used clinically for diverse problems, including the treatment of vascular headache and improvement of mental function in pre-senile dementia. 

Clinical Pharmacology of the Alpha-Receptor-Blocking Drugs... 

SCN5A Sodium channel protein type 5 subunit alpha Neuroactive drugs blocking voltage-gated sodium channels 94 76 56 16 61 62 41 40 19 14 - -... 

Drug Group Examples EPS M Block Alpha Block Sedation Other j Characteristics j... 

Drug ANE Reuptake A 5HT Reuptake M Block Alpha Block —i Sedation... 

I The class I antiarrhythmic drugs block Na channels. Class lA drugs are statedependent blockers of I fast Na channels, and they increase the adion potential duration (APD). Quinidine, in addition, is an j M blocker and can increase the heart rate and AV conduction. Procainamide has less M block than I quinidine and no alpha block. The uses and contraindications of quinidine and procainamide are I provided. 

Drug Group Examples EPS <- M Block Sedation Alpha Block Other Characteristics... 

Labetalol is an unusual agent with combined alpha- and beta-blocking action. This drug has four diastereomers the alpha-blocking activity resides in the SR enantiomer and the beta-blocking action in the RR enantiomer. The other two enantiomers (RS and SS) are practically inactive. Carvedilol has two isomers one is an alpha blocker while the other is a nonselective beta-blocker. 

D. Toxicity and Interactions Sedation is common, especially with diphenhydramine, doxylamine, and promethazine. It is much less common with second-generation agents, which do not enter the CNS readily. Antimuscarinic effects such as dry mouth and blurred vision occur with some first-generation drugs in some patients. Alpha-blocking actions may cause orthostatic hypotension. 

Drug Dj Block Block Alpha, Block 5-HTj Block M Block H, Block... 

---