Drug action selectivity

The presence of these differoit subtypes of the a,-AR in blood vessels and other smooth muscles offers the opportunity for selective drug action. Selective antagonists are perhaps the most useful tools for receptor characterization and clas cation. 

Narcotic antagonist. A drug that selectively blocks the actions of morphine-like compounds. 

Ganter B, Tugendreich S, Pearson Cl, Ayanoglu E, Baumhueter S, Bostian KA, et al. Development of a large-scale chemogenomics database to improve drug candidate selection and to understand mechanisms of chemical toxicity and action. J Biotechnol 2005 119 219-44. 

The mechanism of action proposed is based on a direct binding to the channel and the following partial block of the ATP-binding pocket of CFTR (French et al., 1997), a mechanism similar to that used by genistein to inhibit the activity of other ATP-utilizing enzymes such as protein kinases and topoisomerase II (Polkowski and Mazurek, 2000 and refs therein). The selection of flavonoid compounds or the development of synthetic drugs reasonably selective for CFTR activation might be an area for future clinical trials. 

For each patient, select the mechanism of drug action ... 

The figure below illustrates proposed sites of action of drugs. Tor each drug listedt select the site of action that the drug is most likely to inhibit (a, a receptor iT J3 receptor COMTt cat e cho l-O-methyl transferase MAOt monoamine oxidase NET norepinephrine NMNt normetanephrine). 

This chapter considers the effects of indolealkylamine (LSD-like) and phenyl-alkylamine (mescaline-like) hallucinogens on learned behavior. We concentrate on those approaches that have shed the most light on underlying neuronal mechanisms or that show promise of becoming useful (in vivo) animal models of hallucinogenic drug action. Thus we are selective rather than exhaustive, a luxury made possible in part because several more empirically oriented reviews have been published recently (14,16,34,35). 

This book provides tlie reader with a variety of practice MCQs, which can be used to assess essential pharmacy practice knowledge in a number of areas, including drug action, uses, clinical pharmacology, adverse effects, pharmaceutical care, counselling points, product selection and pharmaceutical calculations. It will be a very useful text both for pharmacy preregistration examination candidates and for practising pharmacists. 

WARNING Renal impair is the major tox foUow administration instructions Uses CMV retinitis w/ HIV Action Selective inhibition of viral DNA synth Dose Rx 5 mg/kg IV over 1 h once/wk for 2 wk w/ probenecid Maint 5 mg/kg IV once/2 wk w/ probenecid (2 g PO 3 h prior to cidofovir, then 1 g PO at 2 h 8 h after cidofovir) X in renal impair Caution [C, -] Contra Probenecid or sulfa allergy Disp Inj SE Renal tox, chills, fever, HA, NA /D, thrombocytopenia, neutropenia Interactions t Nephrotox W/ aminoglycosides, amphot icin B, foscar-net, IV pentamidine, NSAIDs, vancomycin t effects W/zidovudine EMS Monitor ECG for hypocalcemia (t QT int val) and hypokalemia (flattened T waves) OD May cause renal failure hydration may be effective in reducing drug levels/effects Cilostazol (Pletal) TAntiplatelet, Arterial Vasodilator/ Phosphodiesterase Inhibitor] Uses Reduce Sxs of intermittent claudication Action Phosphodiesterase in inhibitor t s cAMP in pits blood vessels, vasodilation inhibit pit aggregation Dose 100 mg PO bid, 1/2 h before or 2 h after breakfast dinner Caution [C, +/-] Contra CHE, hemostatic disorders. 

Absolute selectivity of drug action does not exist. Any given effector tissue probably contains more than one receptor subtype, and it is likely that the proportion of receptor subtypes varies within that effector. Nevertheless, the designation of a drug as a selective agent for either a Pi-receptor or a P2-receptor seems both useful and justified if one keeps in mind that the designation represents a shorthand notation for what is only a predominance of activities. 

Unlike thiabendazole, mebendazole (Vernwx) does not inhibit fumarate reductase. While mebendazole binds to both mammalian and nematode tubuhn, it exhibits a differential affinity for the latter, possibly explaining the selective action of the drug. The selective binding to nematode tubulin may inhibit glucose absorption, leading to glycogen consumption and ATP depletion. 

The pharmacological agents useful in this disorder may be grouped under five broad categories of treatment (Table 64.2). Such a classification system takes into account the mode of drug action, the route of administration, and the means by which target organ selectivity is achieved. 

---