A patient who has received an oral medication for treatment of ...

[cabate]

A patient who has received an oral medication for treatment of hives says, How long will it be before my skin clears and quits itching? Which concepts should the nurse consider when formulating a response? Note: Credit will be given only if all correct choices and no incorrect choices are selected. Standard Text: Select all that apply.
 
  1. The amount of time between administration and the drug taking effect is known as onset of action.
 
  2. Peak plasma levels rarely occur with oral medications.
 
  3. Duration of action is the amount of time a drug is effective.
 
  4. Peak plasma level is dependent on the drug's plasma half-life (t1/2).
 
  5. Drugs with short half-lives are ineffective in treating systemic illnesses.

Question 2

The nurse is reviewing the role of diffusion in the distribution of medications. Drugs that cannot be distributed by simple diffusion include those with which characteristics? Note: Credit will be given only if all correct choices and no incorrect choices are selected. Standard Text: Select all that apply.
 
  1. Large molecules
  2. Ionization
  3. Water-soluble agents
  4. Alcohol
  5. Urea

[b614102004]

Answer to Question 1

1,3

Rationale 1: Onset of drug action represents the amount of time it takes to produce a therapeutic effect after drug administration.

Rationale 2: All medications have a peak plasma level.

Rationale 3: Duration of drug action is the amount of time a drug maintains its therapeutic effect.

Rationale 4: Peak plasma level and plasma half-life (t1/2) are related but not strictly dependent on one another.

Rationale 5: The effectiveness of a drug is not dependent on half-life as long as dosing frequency is correct.

Global Rationale: Onset of drug action represents the amount of time it takes to produce a therapeutic effect after drug administration. All medications have a peak plasma level. Duration of drug action is the amount of time a drug maintains its therapeutic effect. Peak plasma level and plasma half-life (t1/2) are related but not strictly dependent on one another. The effectiveness of a drug is not dependent on half-life as long as dosing frequency is correct.

Answer to Question 2

1,2,3
Rationale 1: Large molecules have difficulty crossing plasma membranes by simple diffusion.
Rationale 2: Ionized drugs have difficulty crossing plasma membranes by simple diffusion. These drugs may require carrier, or transport, proteins to cross membranes.
Rationale 3: Water-soluble agents have difficulty crossing plasma membranes by simple diffusion.
Rationale 4: Diffusion assumes that the chemical is able to freely cross the plasma membrane. Drugs may also enter through open channels in the plasma membrane; however, the molecule must be very small, such as alcohol.
Rationale 5: Diffusion assumes that the chemical is able to freely cross the plasma membrane. Drugs may also enter through open channels in the plasma membrane; however, the molecule must be very small, such as urea.
Global Rationale: Large molecules have difficulty crossing plasma membranes by simple diffusion. Ionized drugs have difficulty crossing plasma membranes by simple diffusion. These drugs may require carrier, or transport, proteins to cross membranes. Water-soluble agents have difficulty crossing plasma membranes by simple diffusion. Diffusion assumes that the chemical is able to freely cross the plasma membrane. Drugs may also enter through open channels in the plasma membrane; however, the molecule must be very small, such as alcohol or urea.

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[b614102004]

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