P-blocking drugs

Analysis of the enantiomeric ratios of several p-blocking drugs (l-aryloxy-3-isopropylamino-2-propanol derivatives) is carried out by HPLC with UV or fluorescence detection after derivatization with (R)-NEI or (i )-(+)-l-(l-phenyl)ethyl isocyanate (in a reversed-phase system), or (S)-NEI (on silica gel) only the amine function of the drugs reacts with the NEI the hydroxy group does not. Similar schemes for HPLC determination of enantiomeric purity of tetrahydrofolate derivatives and of fluoxetine are also reported. 

Many p-blocking drugs (propranolol, oxprenolol, alprenolol, acebutolol, labetalol) also... 

Betts TA, Crowe A, Kni t R, Raffle A, Parsons A, Blake A, Hawksworth G, Petrie JC. Is there a clinically relevant interaction between diazepam and lipophilic p-blocking drugs Drugs (1983) 25 (Suppl 2), 279-80. 

Class II antiarrhythmic drugs include beta (( -adrenergic blocking drugs, such as acebutolol (Sectral), esmolol (Brevibloc), and propranolol (Inderal). These drugp also decrease myocardial response to epinephrine and norepinephrine (adrenergic neurohormones) because of their ability to block stimulation of p receptors of the... 

Esmolol hydrochloride is a competitive p-adrenergic receptor antagonist it is selective for pT adrenoceptors. In contrast to pindolol, esmolol has little intrinsic sympathomimetic activity, and it differs from propranolol in that it lacks membrane stabilizing activity Of all of the p-adrenergic blocking drugs, this compound has the shortest duration of action because it is an ester, it is hydrolyzed rapidly by plasma esterases and must be used by the intravenous route Esmolol is approved only for the treatment of supraventricular arrhythmias... 

Schumann W, Turner P (1978) Membrane model of the human oral mucosa as derived from buccal absorption performance and physicochemical properties of the beta-blocking drugs atenolol and propranolol. J Pham Pharmacol 30 137-147... 

Wright P. Ocular reactions to beta-blocking drugs. BMJ 1975 4 577. 

Labetalol Normodyne, Trandate) possesses both p-blocking and a-blocking activity and is approximately one-third as potent as propranolol as a p-blocker and one-tenth as potent as phentolamine as an a-blocker. The ratio of p- to a-activity is about 3 1 when labetalol is administered orally and about 7 1 when it is administered intravenously. Thus the drug can be most conveniently thought of as a p-blocker with some a-blocking properties. 

A fine resting tremor is a common side effect. P-Adrenergic-blocking drugs, such as propranolol (<80 mg/day in divided doses), are effective in treating this tremor. Subjective memory impairment commonly occurs and is among the most frequent reasons for noncomphance (Goodwin and Jamison 1990). 

Morris, S., Narcotic lollipop denounced group urges FDA to block drug, says painkiller endangers kids lives, Chicago Tribune, p. 1, January 26, 1994. 

Le Brun, P.P.H., et al. 1989. In vitro penetration of some beta-adrenoreceptor blocking drugs through porcine buccal mucosa. Int J Pharm 49 141. 

Batrakova, E., et al. 2003. Optimal structure requirements for pluronic block copolymers in modifying P-glycoprotein drug efflux transporter activity in bovine brain microvessel endothelial cells. J Pharmacol Exp Ther 304 845. 

A large number of prescription and nonprescription drugs, as well as a variety of plants and mushrooms, can inhibit the effects of acetylcholine. Many drugs used for other purposes (eg, antihistamines) also have anticholinergic effects. Many of them have other potentially toxic actions as well—eg, antihistamines such as diphenhydramine can cause seizures tricyclic antidepressants, which have anticholinergic, quinidine-like, and p-blocking effects, can cause severe cardiovascular toxicity. 

The a adrenoceptors are subdivided into two groups, ai and a2, based on their affinities for a agonists and blocking drugs. For example, the a receptors have a higher affinity for phenylephrine (see p. 66) than do the a2 receptors. Conversely, the drug cloni-dine (see p. 67) selectively binds to a2 receptors, and has less effect on a-i receptors. 

Acquas E, Carboni E, Leone P, Di Chiara G (1989) SCH 23390 blocks drug-conditioned place preference and place-aversion anhedonia (lack of reward) or apathy (lack of motivation) after dopamine-receptor blockade. 

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