Which statement(s) about variables that influence drug action is/are true? (Select all that apply.)

Correct Answer: A

Rationale: The correct answer is A because as people age, physiological changes can impact drug metabolism and clearance. Older adults may require a higher dosage to achieve the same therapeutic effect as younger individuals. This is due to factors such as decreased organ function and changes in body composition. Choice B is incorrect because body weight can affect drug distribution and dosing but not always the therapeutic response directly. Choice C is incorrect as smoking can affect drug metabolism but not always result in faster metabolism. Choice D is incorrect as attitude and expectations may influence placebo effects but not directly impact drug action.

Correct Answer: B

Rationale: The correct answer is B: Caspofungin. This drug is appropriate for systemic antifungal treatment as it inhibits the synthesis of beta-glucan in fungal cell walls. It is effective against a broad spectrum of fungal infections. Amphotericin B (A) is also a systemic antifungal but is associated with more severe side effects. Piperacillin (C) is an antibiotic not used for antifungal treatment. Metronidazole (D) is an antiprotozoal and antibiotic, not effective against systemic fungal infections.

Correct Answer: D

Rationale: The correct answer is D: Amphotericin B and fluconazole. Amphotericin B is an antifungal medication used for severe fungal infections, while fluconazole is commonly used for less severe fungal infections. The combination of these two drugs would be most likely given to treat a severe fungal infection that requires immediate and potent treatment. A: Amphotericin B and terbinafine - Terbinafine is primarily used to treat fungal infections of the skin and nails, not severe systemic fungal infections. B: Caspofungin and griseofulvin - Griseofulvin is used to treat superficial fungal infections like ringworm, while caspofungin is used for systemic fungal infections. C: Caspofungin and metronidazole - Metronidazole is an antibiotic used to treat bacterial and parasitic infections, not fungal infections.

Correct Answer: A

Rationale: Step 1: Chloroquine is a known antimalarial drug that targets Plasmodium species by inhibiting their ability to replicate within red blood cells. Step 2: Amoxicillin is an antibiotic effective against bacteria, not parasites like Plasmodium. Step 3: Levofloxacin and Ciprofloxacin are also antibiotics that target bacterial infections, not malaria caused by Plasmodium species.

Correct Answer: A

Rationale: The correct answer is A: Binding to opioid receptors in the brain. Oxycodone is an opioid analgesic that works by binding to opioid receptors in the brain, spinal cord, and other parts of the body to reduce pain perception. Opioid receptors are primarily located in the central nervous system and play a crucial role in pain modulation. By binding to these receptors, oxycodone can produce analgesic effects. Choices B, C, and D are incorrect: B: Inhibiting the reuptake of serotonin and norepinephrine is a mechanism of action for some antidepressants, not opioids like oxycodone. C: Inhibiting prostaglandin synthesis is a mechanism of action for nonsteroidal anti-inflammatory drugs (NSAIDs), not opioids like oxycodone. D: Increasing dopamine release is a mechanism of action for certain stimulant medications, not opioids like oxycodone.