ATI RN
Basic principles of pharmacology Questions
Question 1 of 5
Regarding termination of drug action
Correct Answer: D
Rationale: Hepatic metabolism and renal excretion are the two most important mechanisms involved (D) in terminating drug action. The liver metabolizes drugs into inactive or more excretable forms, while the kidneys filter and excrete them, as seen with many drugs like penicillin. Option A is incorrect because redistribution (e.g., thiopental moving from brain to fat) can terminate action without excretion. Option B is false; metabolism can produce lipid-soluble metabolites (e.g., morphine to morphine-6-glucuronide). Option C is wrong as some metabolites retain activity (e.g., diazepam to nordazepam). Option E (original) about distribution is a mechanism but less dominant than metabolism and excretion. These processes ensure drug clearance, balancing efficacy and toxicity, with liver and kidney function critical to dosing adjustments in disease states.
Question 2 of 5
The 'dominant lethal' test involves the treatment of a male adult animal with a chemical before mating; the pregnant female is later examined for fetal death and abnormalities. The dominant lethal test therefore is a test of
Correct Answer: B
Rationale: The dominant lethal test is a test of mutagenicity (B), detecting mutations in male germ cells causing fetal death or abnormalities post-mating, indicating DNA damage (e.g., from alkylating agents). Teratogenicity (A) tests developmental defects from maternal exposure during pregnancy, not paternal. Carcinogenicity (C) assesses tumor formation, requiring long-term studies. Option D is incorrect as it's specific to mutagenesis. Option E (original) is also false. Used in toxicology, this assay identifies genotoxic potential, critical for assessing reproductive risks of chemicals, though it doesn't predict teratogenesis or cancer directly.
Question 3 of 5
Most drug receptors are
Correct Answer: C
Rationale: Most drug receptors are proteins located on cell membranes or in the cytosol (C), such as G-protein-coupled receptors (e.g., beta-adrenergic) or intracellular nuclear receptors (e.g., steroid receptors), mediating specific drug effects. Small molecules (A) like neurotransmitters aren't receptors. Lipids (B) form membranes, not receptors. DNA (D) and RNA (original E) are targets for some drugs (e.g., chemotherapy), not typical receptors. Proteins' structural diversity enables ligand binding and signal transduction, fundamental to pharmacodynamics, distinguishing receptor-mediated effects from non-specific actions like osmosis.
Question 4 of 5
Which equation is used to predict the stability of a drug product at room temperature from experiments at accelerated temperature?
Correct Answer: C
Rationale: The Arrhenius equation (C), k = Ae^(-Ea/RT), predicts drug stability at room temperature by relating reaction rate (k) to temperature (T), using activation energy (Ea) from accelerated studies (e.g., 40°C). Stokes (A) addresses viscosity, Yong (B) is undefined here, Michaelis-Menten (D) is enzyme kinetics, and Hixson-Crowell (original E) models dissolution. This exponential relationship extrapolates shelf life (e.g., 25°C) from higher-temperature degradation rates, critical in pharmaceutical development for ensuring potency and safety over time.
Question 5 of 5
In the fusion method of making cocoa butter suppositories, which substance is most likely to be used to lubricate the mold?
Correct Answer: A
Rationale: Mineral oil (A) is most likely used to lubricate molds in the fusion method for cocoa butter suppositories, preventing sticking and ensuring easy release post-cooling. Propylene glycol (B) is a humectant, not a lubricant. Cetyl alcohol (C) and stearic acid (D) are base components, not mold lubricants. Magnesium silicate (original E) is a filler, not suitable. Mineral oil's inert, oily nature facilitates clean suppository production, maintaining shape and drug uniformity (e.g., bisacodyl), a practical step in extemporaneous compounding.