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naplex22

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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.

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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

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  • 1 month later...

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.

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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

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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%

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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%

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