Nokea
Several classes of drugs have interactions with cholinergic blockers. Which of the following is true about these interactions?
- A. Drugs with a narrow therapeutic range given orally may not stay in the GI tract long enough to produce an action.
- B. Additive antimuscarinic effects may occur with antihistamines.
- C. Cholinergic blockers may decrease the sedative effects of hypnotics.
- D. Cholinergic blockers are contraindicated with antipsychotics.
Correct Answer: B
Rationale: Additive antimuscarinic effects with antihistamines can enhance side effects like sedation.
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Which antiepileptic drug does not act as GABA agonist?
- A. Phenytoin
- B. Sodium valproate
- C. Diazepam
- D. Phenbarbitone
Correct Answer: A
Rationale: Phenytoin blocks sodium channels, not GABA-related.
The nurse is aware that for a drug to work properly on reactive tissues, a sufficient amount of the drug is needed to cause the therapeutic effect. The term used for this amount is:
- A. Critical concentration
- B. Dynamic equilibrium
- C. Selective toxicity
- D. Active transport
Correct Answer: A
Rationale: A critical concentration of a drug must be present before a reaction occurs within our cells. A dynamic equilibrium is obtained from absorption of a drug from the site of drug entry, distribution to the active site, metabolism in the liver, and excretion from the body to have a critical concentration. Selective toxicity is the ability of a drug to attach only to those systems found in foreign cells. Active transport is the process that uses energy to actively move a molecule across a cell membrane and is often involved in drug excretion in the kidney.
Zero order kinetics are seen in all except
- A. Salicylate
- B. Atenolol
- C. Barbiturates
- D. Ethanol
Correct Answer: C
Rationale: Barbiturates typically follow first-order kinetics; others exhibit zero-order at high doses.
A physician has ordered intramuscular (IM) injections of morphine, a narcotic, every 4 hours as needed for pain in a motor vehicle accident victim. The nurse is aware this drug has a high abuse potential. Under what category would morphine be classified?
- A. Schedule I
- B. Schedule II
- C. Schedule III
- D. Schedule IV
Correct Answer: B
Rationale: Narcotics with a high abuse potential are classified as Schedule II drugs because of severe dependence liability. Schedule I drugs have high abuse potential and no accepted medical use. Schedule III drugs have a lesser abuse potential than II and an accepted medical use. Schedule IV drugs have low abuse potential and limited dependence liability.
A patient presents to the emergency department with a drug level of 50 units/mL. The half-life of this drug is 1 hour. With this drug, concentrations above 25 units/mL are considered toxic and no more drug is given. How long will it take for the blood level to reach the non-toxic range?
- A. 30 minutes
- B. 1 hour
- C. 2 hours
- D. 3 hours
Correct Answer: B
Rationale: Half-life is the time required for the serum concentration of a drug to decrease by 50%. After 1 hour, the serum concentration would be 25 units/mL (50/2) if the body can properly metabolize and excrete the drug. After 2 hours, the serum concentration would be 12.5 units/mL (25/2) and reach the nontoxic range. In 30 minutes the drug level would be 37.5 units/mL, whereas in 3 hours the drug level would be 6.25.