03-13-2008, 10:19 PM
td50 and ed50 of some drugs given,which one is safest?
td50 2.8, ed50 0.5
td50 2.1 ed50 1
td50 3 ed50 33
td50 4 ed50 5
td50 2.8, ed50 0.5
td50 2.1 ed50 1
td50 3 ed50 33
td50 4 ed50 5
|
pharma cbt q - guest78
|
03-13-2008, 10:31 PM
answer wise its wrong,but why,i need the explanation.....
03-13-2008, 10:55 PM
hi,jhana,can u pls clear this confusion?
and another q: in a rapid metaboliser what will happen to Cp and CL of the drug and what change should be made in loading dose and maintenance dose?
03-13-2008, 11:39 PM
answer of above is bb...coz td50 is a mraker of safety...
03-13-2008, 11:58 PM
harsh, marker of safety is td50 or therapeutic index?
can u pls explain why the ans is b? and the other q too?
03-14-2008, 05:51 AM
i think someone shld pls explain this one. i dont get it also.why b?
03-14-2008, 06:41 AM
This is also a usmle cd question, but the question there asks, least safe - and attached is respective explanation.Hope this helps...
This question appears much more difficult than it really is. The x in this case represents any random unit, such as milligrams. As you know, drugs come in all sorts of dosages. Some drugs are in the 10 mg range, whereas other drugs such as Extra Strength Tylenol® are 500 mg per pill. Therefore, the column on the left, median effective dose, is merely a distraction from the real answer. The (toxic dose)/(effective dose) is also known as the therapeutic index. The lower the therapeutic index, the less amount of effective dose is required before the drug becomes toxic. A good example of this is warfarin. Therefore, in this case, the drug with the lowest therapeutic index, 2.1, is most likely to have the highest incidence of toxicity at the maximally effective therapeutic dose.
03-14-2008, 06:47 AM
as far as i know safety of drug is determined by TI so it should be A
for eg. if X and Y are two diff drugs which could be used for same dis. and if X has effective dose of 1mg and toxic dose of 50mg (for 50% of pt.s) and Y has effective dose of 1mg and toxic dose of 5 mg i would definitely want to use X becuase it takes lot of dosing to get toxic effects...and it has TI of 50 further more TI of min above 2 is considered safe.. choice b has TI of 2.1 which is in border.. dont know why b is given as ans. where did u get this q guest78? if TI of two drugs is same then the safety of each depends on shape of curves.. other wise it should be TI 2. if metabolism increases.. more drug removed per unit time per ml of blood.. so CL increases.. loading dose depends on volume of distribution and maintanance dose on CL. so if metabolism of a drug increases.. then no change in loading dose and increase in maintanance dose.. (wht is Cp?) |
| « Next Oldest | Next Newest » |