The following antiemetic is incorrectly matched to its mechanism of action?

Correct Answer: B

Rationale: In this question on basic pharmacology principles, the correct answer is B) Ondansetron: Serotonin agonist. Ondansetron is a 5-HT3 receptor antagonist, not agonist, making it effective in treating nausea and vomiting by blocking serotonin receptors in the gut and central nervous system. A) Metoclopramide is a dopamine antagonist, not incorrectly matched. C) Diphenhydramine is an antihistamine commonly used as an antiemetic, making this option incorrect. D) Scopolamine is a muscarinic antagonist used for motion sickness and post-operative nausea, hence this option is also correctly matched. Understanding the mechanisms of action of antiemetics is crucial for healthcare professionals to effectively manage patients experiencing nausea and vomiting. This knowledge helps in selecting the most appropriate medication based on the underlying cause of symptoms and individual patient factors. It also underscores the importance of accurate drug classification to ensure safe and effective treatment outcomes.

Correct Answer: D

Rationale: The correct answer is D) Direct antimicrobial & decrease PG synthesis. Bismuth subsalicylate is used in the management of diarrhea because it has direct antimicrobial properties, helping to kill or inhibit the growth of certain bacteria and parasites that can cause diarrhea. It also decreases prostaglandin synthesis in the intestine, which helps to reduce inflammation and fluid secretion, ultimately leading to a decrease in diarrhea. Option A) Provide a protective coat & adsorb toxins: While bismuth subsalicylate may have some protective coating properties, its main mechanism of action in managing diarrhea is through its antimicrobial and anti-inflammatory effects, rather than solely providing a protective coat and adsorbing toxins. Option B) Bulk forming, decreasing stool liquidity: This is typically the mechanism of action for agents like fiber supplements or certain laxatives. Bismuth subsalicylate works through different mechanisms as described above. Option C) Opioid-related combined with atropine: This describes the drug loperamide with atropine, which is used to slow down gut motility and reduce diarrhea, but it is not the mechanism of action of bismuth subsalicylate. In an educational context, understanding the specific mechanisms of action of different drugs used in managing diarrhea is crucial for healthcare professionals to make appropriate treatment decisions based on the underlying cause of diarrhea in individual patients. This knowledge helps in selecting the most effective treatment and minimizing potential side effects.

Correct Answer: C

Rationale: The correct adverse effect for Paraffin oil is C) Lipid pneumonia. Paraffin oil is a mineral oil sometimes used as a laxative. When ingested, it can lead to lipid pneumonia, a condition where the oil enters the lungs and causes inflammation and respiratory distress. This adverse effect is specific to Paraffin oil due to its physical properties and how it can be aspirated into the lungs. Option A) Intestinal obstruction if not taken with plenty of fluids is incorrect because Paraffin oil is actually used as a laxative to relieve constipation, although it is important to take it with sufficient fluids to prevent dehydration. Option B) Mutagenic is incorrect because Paraffin oil is not known to have mutagenic properties. Mutagenic substances can cause changes in DNA leading to mutations, but this is not a known effect of Paraffin oil. Option D) Flatulence & aggravation of diabetes is incorrect as these are not commonly associated adverse effects of Paraffin oil. Flatulence can occur with some laxatives, but it is not a specific adverse effect of Paraffin oil. Aggravation of diabetes is not a known effect of Paraffin oil use. In an educational context, understanding the specific adverse effects of drugs is crucial for healthcare professionals to provide safe and effective care to patients. Pharmacology principles help in understanding how drugs work in the body, their potential side effects, and how to monitor and manage these effects to ensure patient safety and well-being. This question highlights the importance of knowing the specific adverse effects of medications to avoid potential harm to patients.

Correct Answer: C

Rationale: In this question, option C is the correct statement: "50% of the dose of famotidine is decomposed by gastric acidity." This is correct because famotidine is a histamine-2 receptor antagonist that works by reducing the amount of acid produced by the stomach. Gastric acidity can indeed degrade some medications, including famotidine, hence the need for specific formulations or dosages to ensure effectiveness. Option A is incorrect because lansoprazole is a proton pump inhibitor that needs to be absorbed in the small intestine, not the stomach, to be effective in reducing stomach acid production. Option B is incorrect as acid suppressants, including famotidine, actually work by decreasing acid production, which would not increase the activity of sucralfate, a different type of medication that forms a protective barrier over ulcers. Option D is also incorrect as misoprostol, a prostaglandin analog, is known to actually reduce constipation by promoting the secretion of mucus in the gastrointestinal tract. Educationally, understanding the mechanisms of action and proper administration of medications is crucial for healthcare professionals to ensure safe and effective patient care. This question highlights the importance of knowing how different drugs interact with the body and each other, emphasizing the need for accurate pharmacological knowledge in clinical practice.

Correct Answer: B

Rationale: The correct answer is B) Action completely reversed by naloxone. Pethidine and tramadol are both analgesics, making option A correct. However, pethidine's action is not completely reversed by naloxone, which is an opioid antagonist. This is because pethidine has additional effects beyond opioid receptor binding that contribute to its analgesic properties. Tramadol, on the other hand, has a more complex mechanism of action involving weak mu-opioid receptor binding and inhibition of serotonin and norepinephrine reuptake. Option C states that both pethidine and tramadol have less respiratory depression than morphine, which is a characteristic feature of these drugs compared to traditional opioids like morphine. Option D is incorrect because while high doses of pethidine can indeed increase the risk of convulsions, tramadol is not known for causing convulsions even at high doses. In an educational context, understanding the unique characteristics of different analgesics is crucial for healthcare professionals to make informed decisions when selecting the most appropriate medication for pain management. Knowledge of these distinctions can help prevent adverse effects and ensure optimal patient care.