Which of the following drugs is a 5-lipoxygenase (5-LOG) inhibitor?

Correct Answer: B

Rationale: In pharmacology, understanding the mechanisms of action of different drugs is essential. In this case, the correct answer is B) Zileuton (Zyflo), which is a 5-lipoxygenase (5-LO) inhibitor. 5-LO is an enzyme involved in the production of leukotrienes, which are inflammatory mediators. By inhibiting 5-LO, Zileuton helps reduce inflammation in conditions like asthma. Now, let's discuss why the other options are incorrect: A) Ibuprofen - Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that works by inhibiting cyclooxygenase (COX) enzymes, not 5-LO. C) Metamizole (Analgin) - Metamizole is a non-opioid analgesic with antipyretic properties, but it does not inhibit 5-LO. D) Diclofenac - Diclofenac is another NSAID that inhibits COX enzymes, not 5-LO. Educational context: Understanding the specific mechanisms of action of different drugs helps pharmacology students make informed decisions in clinical practice. Knowing that Zileuton targets 5-LO can guide healthcare providers in choosing the right medication for patients with conditions where leukotrienes play a significant role in pathology, such as asthma or inflammatory disorders. This knowledge also aids in preventing adverse drug interactions and optimizing therapeutic outcomes.

Correct Answer: D

Rationale: In this question, the correct answer is D) All of the above. Coenzyme Q10, magnesium, and carnitine are not coenzymes of vitamin origin. Coenzyme Q10 is a vital compound in the electron transport chain and is synthesized in the body, not derived from a vitamin source. Magnesium is an essential mineral that acts as a cofactor for many enzymatic reactions but is not a coenzyme derived from a vitamin. Carnitine is a compound synthesized from the amino acids lysine and methionine, not a vitamin-derived coenzyme. The educational context here is to highlight the diversity of compounds involved in cellular processes and to emphasize that not all essential cofactors are derived from vitamins. Understanding the origins and functions of coenzymes and essential minerals like magnesium is crucial in pharmacology, especially in the context of cardiovascular drugs where these compounds play significant roles in various pathways and mechanisms.

Correct Answer: A

Rationale: In patients with homozygous familial hypercholesterolemia (type IIa), the lack of functional LDL receptors on hepatocytes is a characteristic feature. This is because individuals with this condition inherit two defective copies of the gene responsible for encoding the LDL receptor, leading to a significant reduction in the liver's ability to remove LDL cholesterol from the bloodstream. Option A is correct because the absence of functional LDL receptors is a key pathophysiological mechanism in homozygous familial hypercholesterolemia. Option B is incorrect because it contradicts the well-established understanding of the genetic basis of this condition. Option C and D are also incorrect as they do not accurately reflect the specific genetic defect seen in homozygous familial hypercholesterolemia. Educationally, understanding the role of LDL receptors in cholesterol metabolism is crucial in the context of cardiovascular pharmacology. This knowledge is essential for healthcare professionals in diagnosing, managing, and treating patients with hypercholesterolemia and other cardiovascular conditions.

Correct Answer: D

Rationale: In pharmacology, understanding the route of administration of a drug is crucial as it directly impacts its absorption, distribution, metabolism, and excretion. In the case of cholecalciferol, which is a form of vitamin D, the correct route of administration is oral (Option D). Cholecalciferol is a fat-soluble vitamin that is commonly taken orally in the form of supplements. The oral route is preferred for cholecalciferol because it is well-absorbed in the gastrointestinal tract and can be effectively metabolized in the liver to its active form. Subcutaneous (Option A), intranasal (Option B), and intravenous (Option C) routes are not typically used for cholecalciferol administration. Subcutaneous administration may not provide optimal absorption, intranasal administration may not be suitable for a fat-soluble vitamin like cholecalciferol, and intravenous administration is generally reserved for situations where oral administration is not feasible or in cases where rapid effects are needed. Educationally, this question highlights the importance of understanding the appropriate routes of administration for different drugs based on their pharmacokinetic properties and clinical indications. It reinforces the concept that the route of administration plays a significant role in determining the drug's effectiveness and safety for the patient.

Correct Answer: A

Rationale: In the context of pharmacology, understanding how drugs act on specific sites in the body is crucial. In this case, the correct answer is A) Furosemide (Lasix) because it is a loop diuretic that acts on the lumenal side of the renal tubules in the kidneys. Furosemide inhibits the Na+/K+/2Cl- co-transporter in the thick ascending limb of the loop of Henle, leading to increased excretion of water and electrolytes. Option B) Acetazolamide (Diamox) is incorrect because it acts on the proximal convoluted tubule by inhibiting carbonic anhydrase, which leads to decreased reabsorption of bicarbonate and subsequent diuresis. Acetazolamide does not specifically target the lumenal side of the renal tubules like furosemide does. Therefore, understanding the specific mechanisms of action of cardiovascular drugs like furosemide and acetazolamide is essential for healthcare professionals to make informed decisions regarding their use in clinical practice. This knowledge helps in optimizing drug therapy and patient outcomes.