The following drugs are effectively administered by the rectal route to produce their systemic effect:

Correct Answer: C

Rationale: Metronidazole (C) is effective rectally for systemic effects (e.g., anaerobic infections), partially avoiding first-pass metabolism. Indometacin (A) is correct too but C is chosen. Sulfasalazine (B) acts locally. Glycerin (D) is local (laxative). Diazepam (original E) is systemic via rectum. Rectal administration, useful in nausea or unconsciousness, enhances metronidazole's bioavailability, a key alternative route in pharmacology.

Correct Answer: D

Rationale: Metformin (D) must be avoided in severe renal failure (GFR <10 mL/min), risking lactic acidosis due to reduced clearance. Prednisolone (A) and amoxicillin (B) are safe with adjustment. Bumetanide (C) is usable. Oxytetracycline (original E) needs caution but not avoidance. Metformin's renal excretion, critical in diabetes, demands strict contraindication, a key safety concern in renal impairment pharmacology.

Correct Answer: B

Rationale: A is false:acetylation is phase II. B is true:theophylline follows zero-order kinetics at high doses with a narrow index. C is false:first-order eliminates a constant fraction, not amount. D is false:zero-order kinetics doesn't reach steady state predictably. B is correct, reflecting theophylline's clinical monitoring needs.

Correct Answer: D

Rationale: In pharmacology, understanding the concept of volume of distribution is crucial for determining the distribution of a drug within the body. The correct answer, option D - High plasma protein binding, tends to reduce the volume of distribution of a drug. This is because when a drug is highly bound to plasma proteins, it is not readily available to distribute to tissues or cross biological barriers, resulting in a lower volume of distribution. Option A - Low ionization at physiological pH, is incorrect because the ionization state of a drug does not directly impact its volume of distribution. Ionization can affect a drug's solubility and absorption, but not its distribution within the body. Option B - High lipid solubility, is also incorrect because high lipid solubility typically leads to a larger volume of distribution. Lipid-soluble drugs can distribute extensively into fatty tissues, increasing their volume of distribution. Option C - High tissue binding, is incorrect because high tissue binding would also lead to a larger volume of distribution. When a drug is highly bound to tissues, it can accumulate in tissues and increase the volume of distribution. In an educational context, understanding the factors that influence a drug's volume of distribution is essential for pharmacology students and healthcare professionals. It helps in predicting the drug's distribution in different tissues, determining dosing regimens, and understanding the drug's pharmacokinetic profile for effective clinical use.

Correct Answer: B

Rationale: In pharmacology, understanding the principles of drug pharmacokinetics is crucial for determining how drugs move through the body. In this question, option B is the false statement. Urine alkalinization actually increases the excretion of weak acids by trapping them in their ionized form, preventing reabsorption in the renal tubules. Option A is correct because lipid solubility tends to increase renal excretion as lipid-soluble drugs are reabsorbed less in the renal tubules. Option C is incorrect because the addition of bicarbonate actually increases the excretion of weak acids by promoting their ionization. Option D is incorrect because excretion is enhanced by increasing polarity, not decreased. Understanding how different factors affect drug excretion is essential in medication management. Students need to grasp these concepts to optimize drug dosing, minimize side effects, and avoid drug toxicities. It is important for healthcare professionals to be able to predict how a drug will be eliminated from the body based on its physicochemical properties.