The following anti-emetic drug is useful in treatment of motion sickness:

Correct Answer: A

Rationale: The correct answer is A) Dimenhydrinate. Dimenhydrinate is a first-generation antihistamine with antiemetic properties that is commonly used to treat motion sickness. It works by blocking histamine receptors in the brain that are responsible for triggering nausea and vomiting in response to motion. Option B) Chlorpromazine and C) Haloperidol are both typical antipsychotic medications that are not typically used for motion sickness. They work by blocking dopamine receptors in the brain and are more commonly used to treat psychotic disorders or severe nausea and vomiting associated with chemotherapy. Option D) Metoclopramide is a prokinetic agent that works by increasing muscle contractions in the upper digestive tract, which can help to move food and drugs through the stomach more quickly. While it can be used to treat nausea and vomiting related to various causes, it is not typically the first choice for motion sickness. In an educational context, understanding the mechanisms of action of different antiemetic drugs is crucial for healthcare professionals to make informed treatment decisions based on the underlying cause of nausea and vomiting. Knowing the specific indications and contraindications of each drug helps ensure safe and effective management of patients experiencing these symptoms.

Correct Answer: C

Rationale: In this question about cimetidine, the correct answer is C) H1-receptor antagonist. Cimetidine is actually a H2-receptor antagonist, not H1. This is an important distinction in pharmacology since H2-receptor antagonists like cimetidine are commonly used to reduce stomach acid production in conditions like duodenal ulcers, which makes option A correct. Option B, that cimetidine may cause mental confusion, is also true. Cimetidine is known to cross the blood-brain barrier and can lead to central nervous system side effects, including mental confusion. Option D, that cimetidine may cause hepatic dysfunction, is also true as cimetidine has been associated with liver function abnormalities in some patients. Educationally, understanding the specific receptor type targeted by cimetidine (H2 instead of H1) is crucial for selecting the appropriate drug for conditions like duodenal ulcers. This knowledge helps healthcare professionals make informed decisions when prescribing medications. Additionally, recognizing the potential side effects of cimetidine, such as mental confusion and hepatic dysfunction, is essential for monitoring patients and managing their care effectively.

Correct Answer: C

Rationale: In the treatment of diarrhea, it is crucial to understand the mechanisms of action of different drugs affecting gastrointestinal secretions. The correct answer, option C, Muscarinic agonists, is not typically used in the treatment of diarrhea. Muscarinic agonists would stimulate cholinergic receptors, leading to increased gastrointestinal motility and secretions, exacerbating diarrhea symptoms. Option A, Anti-microbial agents, are used to treat infectious causes of diarrhea, such as bacterial or parasitic infections. These agents help eliminate the infectious organism causing the diarrhea. Option B, Fluid replacement, is essential in managing diarrhea to prevent dehydration and electrolyte imbalances caused by fluid loss through loose stools. Replacing lost fluids helps maintain hydration and prevent complications. Option D, Loperamide, is an anti-diarrheal agent that acts by slowing down gut motility and reducing fluid secretion in the intestines, thus helping to alleviate diarrhea symptoms. Educationally, understanding the appropriate use of different medications for treating diarrhea is essential for healthcare professionals. It is crucial to differentiate between drugs that exacerbate diarrhea symptoms, like muscarinic agonists, and those that help alleviate symptoms, like anti-microbial agents, fluid replacement, and anti-diarrheal agents. This knowledge is vital for providing effective and evidence-based care to patients with diarrhea.

Correct Answer: C

Rationale: Rationale: Purgatives, also known as laxatives, are medications used to induce bowel movements. In the context of the question, purgatives are not typically used in the treatment of gastroenteritis. A) Before operations: Purgatives may be used before certain operations to clear the bowel and reduce the risk of complications during surgery due to residual fecal matter. B) After anti-helminthics: Anti-helminthic medications are used to treat parasitic worm infections. Purgatives may be prescribed after these medications to help eliminate the worms from the body. C) Gastroenteritis: Gastroenteritis is characterized by inflammation of the stomach and intestines, leading to symptoms like diarrhea and vomiting. Purgatives are generally not recommended in this condition as they can worsen dehydration and electrolyte imbalances caused by gastroenteritis. D) Oral drug poisoning: In cases of oral drug poisoning, purgatives may be administered to help remove the toxic substance from the gastrointestinal tract before it can be fully absorbed into the bloodstream, reducing the overall toxicity of the ingested substance. Educational Context: Understanding the appropriate use of purgatives is crucial in clinical practice to ensure safe and effective patient care. Knowledge of when to use or avoid purgatives based on different clinical scenarios is essential for healthcare professionals to make informed decisions regarding patient management. This question highlights the importance of considering the underlying condition and individual patient factors when prescribing medications affecting gastrointestinal secretions.

Correct Answer: C

Rationale: Cimetidine is a histamine H2-receptor blocker, not an H1-receptor blocker. Option A is incorrect because cimetidine acts by inhibiting the action of histamine on the H2 receptors in the stomach, thereby reducing gastric acid secretion. Option B is incorrect because cimetidine does not provide a direct protective effect on the gastric mucosa; instead, it primarily works by reducing acid production. Option D is incorrect as cimetidine is known to inhibit the metabolism of other drugs by inhibiting cytochrome P450 enzymes. The correct answer, option C, stating that cimetidine can be complicated by gynecomastia, is accurate. Cimetidine can lead to increased levels of prolactin, which can result in gynecomastia (breast tissue enlargement) in males. This adverse effect is important for healthcare providers to be aware of when prescribing cimetidine to patients. In an educational context, understanding the specific mechanisms of action and potential side effects of drugs affecting gastrointestinal secretions like cimetidine is crucial for healthcare professionals, particularly pharmacists, nurses, and physicians. This knowledge enables them to make informed decisions when selecting appropriate treatment options for patients with gastrointestinal conditions and to monitor for and manage potential adverse effects effectively.