Pharmacology Flashcards Quiz 1 (Day 3)

14 items to memorize for Day 3, do 3 rows at a time until bed

29) What are the 3 parenteral routes of administration?

• Intravenous (IV)

• Intramuscular (IM)

• Subcutaneous (SubQ, SC)

30) What are the advantages of IV drugs?

• Rapid onset of action

• Useful in emergencies

• Useful for unconscious patients

31) What is a disadvantage that is unique to IV drugs?

Drug must be soluble in water to be used as an IV drug.

32) What factor influences the rate of absorption of Intramuscular (IM) and SubQ drugs?

• Oil-based preparations are absorbed slowly

• Aqueous preparations are absorbed rapidly

33) What is a disadvantage that is unique to SubQ drugs? 

Only non-irritating drugs can be used.

34) What is the half-life of a drug?

The amount of time required for the blood concentration of a drug to decrease by 50% after the drug administration has stopped.

35) What does the distribution half-life reflect?

The rapid decline in plasma drug concentration as a dose of drug is distributed throughout the body.

36) What is the speed of the elimination half-life of a drug?

It is much slower, reflecting the metabolism and excretion of the drug.

37) How many half-lives pass before the serum concentration of a drug reaches steady state?

Several

38) How long do you have to wait before you can draw blood to measure the peak, trough or plasma levels of a drug?

Wait until the 4th or 5th half-life

39) If the half-life of a drug is 4 hours, how many hours do you have to wait before measuring its level in the blood?

• After 4 hours, 50% of the drug will be left in the body (first half-life); it will take four more hours to metabolize 50% of the remaining drug; the body will now have 25% of the original dose remaining.

• After the 3rd half-life, the body will have 12.5% of the drug left. After the 4th half-life there will be 6.25% left, and 16 hours will have passed.

• Draw blood at 16-20 hours after drug administration to measure within the 4th–5th half-life.

40) How can therapeutic levels of a drug be obtained more rapidly?

By delivering a loading dose followed by maintenance doses.

41) What is a loading dose? 

An initial dose of drug that is higher than subsequent doses.

42) What is a maintenance dose?

The doses of drug that maintain a steady state plasma concentration in the therapeutic range.