asmi
Forum Hero
Topics: 1043
Posts: 4,609
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Hi,
Can anybody answer these Q's:
1) Encainide-------what is its action ,uses and side effects?
2) Heparin --------does it cause suppression of aldosterone secretion?
does it causes release of lipoprotein lipase?
3)The passive absorption of a drug administered I.V. from tubular urine(PH 5) would be reduced if the drug were:
a) weak base
b)weak acid
c)ionized throughout PH range
D)unionized throughout PH range
E) none
the answer for 3 is a,Can anybody explain why and how?
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| meg
Forum Guru
Topics: 62
Posts: 806
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1) Encainide and Flecainide are Class 1C antiarrhythmics. Block sodium channels, slowing cardiac conduction and heart rate. But they have shown lifethreatening ventricular arrhythmias and and increased mortality with patients with a history of recent MI. Hence, avoided a lot.
2) Wow! thanks Asmi, I did not know about Heparin inhibiting the adrenal aldosterone synthase! Hence suggested use in hyperkalemia. http://www.medinfo.ufl.edu/year2/clinmed/Nephrolo...
And Heparin stimulates Lipoprotein lipase and is used as a diagnostic test for Type 1 hyperlipoproteinemia where the lipoprotien lipase is deficient and hence after IV heparin, there is a cream layer overlying the clear plasma indicating plenty to chylomicrons (hence decreased lipoprotein lipase activity)
3) Yes, the answer is C . When any substance is ionised then its absorption is lesser. When it is ionised it is more polar and less lipid soluble, hence cannot cross the tubular epithelium, unless there are special channels /protein carriers. That is why you alkalinise urine for removing acidic drugs (like Aspirin toxicity), you make the drug more ionised. Refer to the Kaplan notes or any other under Pharmacodynamics section. Kaplan notes has a nice graph showing the amount of unionised substance with change in pH (acidic to basic)
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| asmi
Forum Hero
Topics: 1043
Posts: 4,609
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Hi,
thanks Meg for the answers and explanations.
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