Nokea
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.
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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.
The patient asks the nurse, Is it safe to take over-the-counter (OTC) medications with prescription medications? What is the nurse's best response?(Select one that does not apply.)
- A. OTC medications can interact with prescription medications.
- B. It is important to tell your doctor all medications you take, including OTC.
- C. OTC medications could mask or hide signs and symptoms of a disease.
- D. You should avoid taking any OTC medication when taking prescription drugs.
Correct Answer: D
Rationale: OTC medications can interact with prescription medications or other OTC so it is always important to consult your pharmacist and provider for advice. To provide the most accurate instruction, the health care provider must know all medications taken including dietary supplements, OTC, and prescription. OTC medications could mask or hide symptoms of a disease so it is always important to consult a physician if symptoms persist. OTC medications are not prohibited when taking prescription drugs as long as no drug interaction occurs. How an OTC will impact a prescription medication varies depending on the medications involved, so it is incorrect to say it will make the prescription drug more effective.
Anticholinergic agents, such as benztropine (Cogentin), may be given with a phenothiazine to:
- A. Reduce the chance of tardive dyskinesia
- B. Potentiate the effects of the drug
- C. Reduce the tolerance that tends to occur
- D. Increase central nervous system 4 (iNS) rdey
Correct Answer: A
Rationale: Benztropine reduces EPS, which can precede tardive dyskinesia in phenothiazine use.
Which of the following statements is FALSE?
- A. Selenium sulfide is used to treat seborrheic dermatitis of scalp
- B. Gamma-benzen hexachloride is effective against scabies
- C. Psoralens are used in the treatment of vitiligo
- D. Tetannic dioxide is an absorbent sunscreen
Correct Answer: D
Rationale: Titanium dioxide is a reflective, not absorbent, sunscreen.
Which of the following drug shows foetal hydantoin syndrome?
- A. Alcohol
- B. Phenytoin
- C. Ethosuximide
- D. Phenobarbitone
Correct Answer: B
Rationale: Phenytoin is associated with fetal hydantoin syndrome, characterized by craniofacial abnormalities and growth deficits, due to its teratogenic effects during pregnancy.