Potassium blocker

Figure 12.14 Effect of potassium blocker on cardiac action potential.

Recently, Ghiaroni et al. (2005) opened the possibility that gambierol could be acting as a voltagegated potassium blocker. They used the patch-clamp technique in order to check the gambierol effect on mouse taste cells. Alteration of the activity of those excitable cells could be an explanation for the... 

Despite the discouraging results of the CAST, post-MI patients with complex ventricular ectopy remain at risk for death. Other drugs besides type Ic drugs have been studied, including sotalol. Sotalol is marketed as a racemic mixture of a D- and L-isomer both are type in potassium blockers, but the L-isomer has /3-blocking actions. Chronic therapy with D-sotalol was studied in patients with remote MI complicated by complex ectopy in the Survival With Oral D-Sotalol (SWORD) trial. Unlike in the CAST, D-sotalol treatment was not designed to cause PVC suppression, yet (as in the CAST) the trial was halted prematurely because of excessive mortality in the treatment arm. Again, the presumed reason for this observation was D-sotalol-related pro arrhythmia. Currently, only two antiarrhythmic... 

To prevent radioactive iodides from lodging in the thyroid gland during exposure to excessive radiation, a potential appHcation of iodine acting as a thyroid-blocker has arisen. Eor this purpose potassium iodide was recommended (66). 

Cromakalim (137) is a potassium channel activator commonly used as an antihypertensive agent (107). The rationale for the design of cromakalim is based on P-blockers such as propranolol (115) and atenolol (123). Conformational restriction of the propanolamine side chain as observed in the cromakalim chroman nucleus provides compounds with desired antihypertensive activity free of the side effects commonly associated with P-blockers. Enantiomerically pure cromakalim is produced by resolution of the diastereomeric (T)-a-meth5lben2ylcarbamate derivatives. X-ray crystallographic analysis of this diastereomer provides the absolute stereochemistry of cromakalim. Biological activity resides primarily in the (—)-(33, 4R)-enantiomer [94535-50-9] (137) (108). In spontaneously hypertensive rats, the (—)-(33, 4R)-enantiomer, at dosages of 0.3 mg/kg, lowers the systoHc pressure 47%, whereas the (+)-(3R,43)-enantiomer only decreases the systoHc pressure by 14% at a dose of 3.0 mg/kg. 

Packed column SFC has also been applied to preparative-scale separations [42], In comparison to preparative LC, SFC offers reduced solvent consumption and easier product recovery [43]. Whatley [44] described the preparative-scale resolution of potassium channel blockers. Increased resolution in SFC improved peak symmetry and allowed higher sample throughput when compared to LC. The enhanced resolution obtained in SFC also increases the enantiomeric purity of the fractions collected. Currently, the major obstacle to widespread use of preparative SFC has been the cost and complexity of the instrumentation. 

By themselves, potassium-sparing agents are relatively weak antihypertensives. In general, there are four ways to reduce the activity of the RAS. The first way is the use of p-blockers to reduce renin release from the juxtaglomerular (JG). The second way, the direct inhibition of the activity of renin, although being actively investigated has not been successful in the clinical arena thus far. The third way is to inhibit the activity of the... 

Potassium Competitive Acid Blockers The pregnane X receptor (PXR) is a promiscuous nuclear receptor, that has evolved to protect the body from toxic chemicals. It is activated by a wide variety of xenobiotics including several diugs like rifampicin, hyperforin ( the active ingredient of St. John s wort), clotrimazole and others. PXR heterodimerizes with the... 

Gastric H,K-ATPase inhibitors Potassium competitive acid blockers... 

Poor Metabolizer Phenotype Population Pharmacokinetics Positron Emission Tomography Post-translational Modification Potassium Channels Potassium Competitive Acid Blockers PP... 

Peukert S, Brendel J, Pirard B, Briiggemann A, Below P, Kleemann HW, Hem-merle H, Schmidt W. Identification, synthesis, and activity of novel blockers of the voltage-gated potassium channel Kvl.5. J Med Chem 2003 46 486-98. 

G, Jiang H, Chen K. Structure-based discovery of potassium channel blockers from natural products virtual screening and electrophysiological assay testing. Chem Biol 2003 10 1103-13. 

The Vaughan-Williams classification of antiarrhythmic drugs has been criticized for a number of reasons. The classification is based on the effects of drugs on normal, rather than diseased, myocardium. In addition, many of the drugs may be placed into more than one class. For example, the class IA drugs prolong repolarization/refractoriness, either via the parent drug8,9 or an active metabolite,10 and therefore also maybe placed in class III. Sotalol is also a 3-blocker, and therefore fits into class II. Amiodarone inhibits sodium and potassium channels, is a non-competitive inhibitor of 3-receptors, and inhibits calcium... 

Medications can increase the risk of hyperkalemia in patients with CKD, including angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers, used for the treatment of proteinuria and hypertension. Potassium-sparing diuretics, used for the treatment of edema and chronic heart failure, can also exacerbate the development of hyperkalemia, and should be used with caution in patients with stage 3 CKD or higher. 

ACE-I, angiotensin-converting enzyme inhibitors ARB, angiotensin-receptor blockers AZA, azathioprine CMV, cytomegalovirus CPK, creatinine phos-phokinase CSA, cyclosporine HMG-CoA, 3-hydroxy 3-methylglutaryl coenzyme A reductase K+, potassium LFTs, liver function tests Rl, renal insufficiency SCr, serum creatinine SRL, sirolimus TAC, tacrolimus TMP-SMX, trimethoprim-sulfamethoxazole. 

Sodium channel blockers p-adrenergic blockers Potassium channel blockers Calcium channel blockers Adenosine Digoxin... 

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