Nokea
A drug dose that delivers 10 mg has a half-life of 5 hours. Identify how much drug will remain in the body after one half-life.
Correct Answer: 5 mg
Rationale: A drug's half-life is the time required for one half of an administered dose of a drug to be eliminated by the body, or the time it takes for the blood level of a drug to be reduced by 50%. Therefore, one half of 10 mg equals 5 mg.
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The patient is receiving two different drugs. At current dosages and dosage forms, both drugs have the same concentration of the active ingredient. Which term is used to identify this principle?
- A. Bioequivalent
- B. Synergistic
- C. Proddrugs
- D. Steady state
Correct Answer: A
Rationale: Two drugs absorbed into the circulation in the same amount (in specific dosage forms) have the same bioavailability; thus, they are bioequivalent. A drug's steady state is the physiologic state in which the amount of drug removed via elimination is equal to the amount of drug absorbed from each dose. The term synergistic refers to two drugs, given together, with a resulting effect that is greater than the sum of the effects of each drug given alone. A prodrug is an inactive drug dosage form that is converted to an active metabolite by various biochemical reactions once it is inside the body.
The nurse is administering parenteral drugs. Which statement is true regarding parenteral drugs?
- A. Parenteral drugs bypass the first-pass effect.
- B. Absorption of parenteral drugs is affected by reduced blood flow to the stomach.
- C. Absorption of parenteral drugs is faster when the stomach is empty.
- D. Parenteral drugs exert their effects while circulating in the bloodstream.
Correct Answer: A
Rationale: Drugs given by the parenteral route bypass the first-pass effect. Reduced blood flow to the stomach and the presence of food in the stomach apply to enteral drugs (taken orally), not to parenteral drugs. Parenteral drugs must be absorbed into cells and tissues from the circulation before they can exert their effects; they do not exert their effects while circulating in the bloodstream.
When administering drugs, the nurse remembers that the duration of action of a drug is defined as which of these?
- A. The time it takes for a drug to elicit a therapeutic response
- B. The amount of time needed to remove a drug from circulation
- C. The time it takes for a drug to achieve its maximum therapeutic response
- D. The time period at which a drug's concentration is sufficient to cause a therapeutic response
Correct Answer: D
Rationale: Duration of action is the time during which drug's concentration is sufficient to elicit a therapeutic response. The other options do not define duration of action. A drug's onset of action is the time it takes for the drug to elicit a therapeutic response. A drug's peak effect is the time it takes for the drug to reach its maximum therapeutic response. Elimination is the length of time it takes to remove a drug from circulation.
The nurse is administering medications to the patient who is in renal failure resulting from end-stage renal disease. The nurse is aware that patients with kidney failure would most likely have problems with which pharmacokinetic phase?
- A. Absorption
- B. Distribution
- C. Metabolism
- D. Excretion
Correct Answer: D
Rationale: The kidneys are the organs that are most responsible for drug excretion. Renal function does not affect the absorption and distribution of a drug. Renal function may affect metabolism of drugs to a small extent.
When administering a new medication to a patient, the nurse reads that it is highly protein bound. Assuming that the patient's albumin levels are normal, the nurse would expect which result, as compared to a medication, that is not highly protein bound?
- A. Renal excretion will be faster.
- B. The drug will be metabolized quickly.
- C. The duration of action of the medication will be shorter.
- D. The duration of action of the medication will be longer.
Correct Answer: D
Rationale: Drugs that are bound to plasma proteins are characterized by longer duration of action. Protein binding does not make renal excretion faster, does not speed up drug metabolism, and does not cause the duration of action to be shorter.