naplex22 Posted April 17, 2012 Share Posted April 17, 2012 1)1 tablespoonful of thioridazine solution ( 100mg/cc) is diluted with water up to 1 quart, what is the % of drug in the final solution? a)1.25% b)0.005% c)0.156% d)2.75% Answer: c..please explain how to get it? 2)The recommended therapeutic dose for Levaquin I.V is 7mg/kg/day. The drug has elimination half life of 12hrs. Volume of distribution is 1.2l/kg. What would be the plasma concentration of the drug.? Pt wt 170lbs. What would be the initial plasma concentration of drug in mg/ml? a)10.11 mcg/ml b)23.12 mcg/ml c)5.833 mcg/ml d)33.23 mcg/ml Answer: c 3)The recommended plasma concentration of cipro is 20 mcg/ml. Elimination half life 6hrs. volume distribution 0.5 l/kg. pt weight 155lbs. what would be the rate of infusion in mg/min/ a) 2.25 mg/min b)5.60 mg/min c)1.35mg/min d)1.1mg/min Answer :c Please solve these qs and explain how u solved it. Thanks. Quote Link to comment Share on other sites More sharing options...
shree Posted April 17, 2012 Share Posted April 17, 2012 1)1 quart is 960 cc:1 table spoon is 15 ml. put the values in you will get C Quote Link to comment Share on other sites More sharing options...
naplex22 Posted April 17, 2012 Author Share Posted April 17, 2012 Thank you. I got it. !5ml----1cc=100mg,Hence, 1.5gm/960*100=0.156%I was calculating as 1 teaspoon.I should be careful. Quote Link to comment Share on other sites More sharing options...
Sunitha Siva Posted April 17, 2012 Share Posted April 17, 2012 Hi the answer for 3rd question is Rate of infusion=CssxCL Css=steady state concentration, Cl=clearance Cl=Vd x Ke =0.5l/kg, for 155lbs it is 35.23litres,Ke=0.693/t1/2 Ke=0.693/6=0.1155 Cl=35.23x0.1155=4.068litres/hour we need to calculate dose for doing Css. Vd=Dose/Cp Vd=35.23=dose/20mcg/ml 20mcg=0.02mg/ml since Vd is in litres, 0.02x1000=20 mg in litres Dose=35.23x20=704.6mg Css=Dose/Vd= 704.6/35.23=20mg/litres Rate of infusion-=CssxCl=20x4.068litres/hour=81.36mg/hour as the answer inminutes, you divide by 60 to get 1.35mg/min Quote Link to comment Share on other sites More sharing options...
Sunitha Siva Posted April 17, 2012 Share Posted April 17, 2012 Hi The answer for 2nd question is Vd=1.2l/kg, so 170lbs is 77.27kg so 1.2 x 77.27=92.72litres or 92720 ml Vd=Dose/Cp Cp=plasma concentration Dose/Vd =dose=7mg/kgx77.27kg=540.89mg is 0.54089mcg Cp=0.54089/92720 =5.833mcg/ml Quote Link to comment Share on other sites More sharing options...
naplex22 Posted April 18, 2012 Author Share Posted April 18, 2012 Thanks Sunitha siva for the explanation of problems. I understood. Quote Link to comment Share on other sites More sharing options...
naplex22 Posted June 12, 2012 Author Share Posted June 12, 2012 Please somebody help with Math: 1)5% w/v solution of phenol is diluted by adding 200ml to 4 liters water. What is the strength of the final product? 2)The concentration of codeine in cough syrup is 65mg/30ml. How many ml of diluent should be added to 120 ml of this syrup to obtain a pediatric dos of 1mg/ml? 3)What is the new strength of a solution prepared by diluting with water , 1 pint of a 1:750 strength solution to i gallon? A)) A patient has bradyarrythmia. Choose the drug which will not worsen pt condition? a)verapamil b)sotalol c)digoxin d)amlodipine e)Diltiazem. Quote Link to comment Share on other sites More sharing options...
fpgee07 Posted June 13, 2012 Share Posted June 13, 2012 1). 5% => 5g -- 100 ml ? -- 200 ml => we have 10 g in 200 ml, which will be diluted to 4litters 10g in 4000 ml ? g in 100 ml => so the strength of the final solution is 1000/4000= 0.25 => 0.25 % 2). 65mg in 30 ml => we have 260 mg in 120 ml, to obtain a concentration of 1mg/ml we need 260 ml so we need 140 ml of diluent to add to 120 ml of the syrup. 3). 1 pint of 1/750 will be diluted to 1 gallon ( 8 pints ) 1/750/8 = 1/6000 4). D, The only drug in the list that does not lower HR is amlodipine Quote Link to comment Share on other sites More sharing options...
naplex22 Posted June 15, 2012 Author Share Posted June 15, 2012 1)5% solution is diluted to 200ml so 200ml will have 5g...please explain? All the answers are correct. Quote Link to comment Share on other sites More sharing options...
fpgee07 Posted June 15, 2012 Share Posted June 15, 2012 5% means 5g in 100 ml, so in 200ml you have 10g. When you dilute it to 4000ml, it means that you have 10g in 4000ml. To get the % strength you have to find how many g are in 100ml 10 g -- 4000ml Xg -- 100ml. => X= 10x100/4000=0.25 X= 0.25% Quote Link to comment Share on other sites More sharing options...
naplex22 Posted June 19, 2012 Author Share Posted June 19, 2012 Thanks for the explanation. I thought 5% of solution is diltuted to 200ml..So I am calculating 5gms in 200ml. When are u taking the Exam? 5% means 5g in 100 ml, so in 200ml you have 10g. When you dilute it to 4000ml, it means that you have 10g in 4000ml. To get the % strength you have to find how many g are in 100ml 10 g -- 4000ml Xg -- 100ml. => X= 10x100/4000=0.25 X= 0.25% Quote Link to comment Share on other sites More sharing options...
fpgee07 Posted June 23, 2012 Share Posted June 23, 2012 Hi naplex22, sorry for the late reply......I scheduled my exam for July 07. But, now I feel that I'm not ready. I'm thinking about rescheduling...... Quote Link to comment Share on other sites More sharing options...
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