Which drug goes through extensive first-pass hepatic metabolism?

Correct Answer: C

Rationale: Propranolol goes through extensive first-pass hepatic metabolism. This means that after oral administration, a significant portion of the drug is metabolized by the liver before it reaches systemic circulation. This process reduces the bioavailability of propranolol. As a result, higher doses are often required for oral administration compared to other routes of administration, such as intravenous. Heparin, insulin, nitroglycerine, and warfarin do not undergo extensive first-pass metabolism in the liver.

Correct Answer: B

Rationale: Naloxone is the antidote commonly used to reverse the effects of opioid toxicity, including hydrocodone. Naloxone works by competitively binding to opioid receptors in the brain, displacing the opioid molecules, and reversing their effects. It effectively antagonizes the respiratory depression, sedation, and analgesic effects caused by opioids like hydrocodone. Administering naloxone can quickly reverse these dangerous effects and help restore respiratory function in cases of opioid overdose or toxicity. Naloxone is commonly used in emergency settings and can be administered intravenously, intramuscularly, or intranasally. It is crucial for healthcare providers to be familiar with naloxone and its administration in managing opioid toxicity.

Correct Answer: B

Rationale: Omeprazole belongs to the therapeutic class of antiulcer agents. It is a proton pump inhibitor that works by decreasing the amount of acid produced in the stomach. Omeprazole is commonly used to treat conditions such as gastroesophageal reflux disease (GERD), gastric ulcers, and duodenal ulcers. It helps reduce symptoms such as heartburn, acid reflux, and stomach pain by promoting healing of the stomach lining.

Correct Answer: A

Rationale: Warfarin is an anticoagulant medication that works by inhibiting the production of certain clotting factors in the liver, specifically factors II, VII, IX, and X. By doing so, warfarin prevents the formation of new blood clots. It does not have the ability to dissolve existing blood clots, as that function is typically carried out by different types of medications known as thrombolytics. Warfarin is commonly prescribed to prevent and treat blood clots in conditions such as atrial fibrillation, deep vein thrombosis, and pulmonary embolism.

Correct Answer: C

Rationale: Propranolol goes through extensive first-pass hepatic metabolism. This means that after oral administration, a significant portion of the drug is metabolized by the liver before it reaches systemic circulation. This process reduces the bioavailability of propranolol. As a result, higher doses are often required for oral administration compared to other routes of administration, such as intravenous. Heparin, insulin, nitroglycerine, and warfarin do not undergo extensive first-pass metabolism in the liver.

Correct Answer: B

Rationale: Pharmacodynamics refers to the study of how drugs exert their effects on the body, including the interactions between a drug and its target molecule or receptor leading to a biological response. Understanding a drug's mechanism of action involves determining how it interacts with specific receptors, enzymes, ion channels, or other molecular targets within the body to produce the desired therapeutic effects. Pharmacokinetics, on the other hand, involves the study of how drugs move through the body, including their absorption, distribution, metabolism, and excretion, which although important for determining effective drug dosages and concentrations, does not directly provide insight into how a drug exerts its pharmacological effects. Therapeutic action refers to the overall clinical effect of the drug in treating a specific condition, which is influenced by its pharmacodynamics. Pharmaceutical preparations involve drug formulation and delivery methods, such as tablets, injections, or creams, which affect a drug's bioavailability but do not determine its specific mechanism of action.

Correct Answer: A

Rationale: Mefloquine is an antimalarial drug that can cause hepatotoxicity, so liver enzyme tests are often ordered to monitor for liver damage. Blood glucose, sputum culture, and white blood cell count are not directly related to mefloquine use.

Correct Answer: B

Rationale: Omeprazole is classified as an antiulcer agent. It belongs to the class of medications known as proton pump inhibitors (PPIs), which work by reducing the production of stomach acid. Omeprazole is commonly used to treat conditions such as gastroesophageal reflux disease (GERD), peptic ulcers, and Zollinger-Ellison syndrome. Its main therapeutic effects include reducing stomach acid secretion and promoting the healing of ulcers.

Correct Answer: B

Rationale: The first pass effect refers to the metabolism of a drug as it passes through the liver before reaching the systemic circulation. When a drug is absorbed from the gut lumen, it first enters the portal circulation where it is transported to the liver. In the liver, the drug may undergo metabolic processes that can reduce the amount of active drug reaching systemic circulation. This process can greatly affect the overall bioavailability and effectiveness of the drug. So, the metabolism of the drug en route from the gut lumen to the systemic circulation is primarily due to the first pass effect.