ACT 11 Q4 ORGMED LAB FINALS

Which of the following best describes the mechanism of action of paracetamol (acetaminophen) in the central nervous system?

• Inhibition of cyclooxygenase (COX) enzymes in peripheral tissues

• Activation of cannabinoid receptors

• Modulation of serotonergic pathways

• Inhibition of COX enzymes primarily in the brain, leading to reduced prostaglandin synthesis

Indomethacin is known to have a higher incidence of gastrointestinal side effects compared to other NSAIDs. What is the primary reason for this?

• It is a selective COX-2 inhibitor.

• It has a longer half-life, leading to prolonged exposure.

• It inhibits both COX-1 and COX-2, disrupting protective gastric mucosal barriers.

• It is metabolized to active metabolites that irritate the gastrointestinal tract.

What is the primary therapeutic use of metoclopramide beyond its antiemetic properties?

• Pain relief in osteoarthritis

• Stimulation of gastric emptying in diabetic gastroparesis

• Treatment of bacterial infections

• Reduction of inflammation in rheumatoid arthritis

Benzyl penicillin is effective against certain bacteria due to its mechanism of action. Which of the following best describes this mechanism?

• Inhibition of protein synthesis by binding to the 30S ribosomal subunit

• Disruption of nucleic acid synthesis by inhibiting DNA gyrase

• Inhibition of cell wall synthesis by binding to penicillin-binding proteins (PBPs)

• Interference with metabolic pathways by blocking folate synthesis

Diphenhydramine is commonly used as an antihistamine. What is its primary mechanism of action?

• Inhibition of histamine release from mast cells

• Competitive antagonism of H1 receptors

• Inhibition of leukotriene synthesis

• Activation of H2 receptors to reduce gastric acid secretion

In Thin Layer Chromatography (TLC), what factor can significantly affect the Rf value of a compound?

• The molecular weight of the compound

• The polarity of the solvent used as the mobile phase

• The temperature of the environment during the experiment

• The thickness of the stationary phase

What is the primary advantage of High-Performance Liquid Chromatography (HPLC) over traditional column chromatography?

• HPLC can separate non-volatile compounds.

• HPLC operates under high pressure, allowing for faster separations and higher resolution.

• HPLC requires less solvent than traditional methods.

• HPLC is less sensitive to temperature variations.

What was the result of the test for diphenhydramine in the provided data?

• Negative result with no precipitate

• Violet color (positive result) and white curdy precipitate (positive result)

• Yellow precipitate (negative result)

• Intense violet-blue color (positive result)

Which of the following is a potential serious side effect of metoclopramide when used long-term?

• Gastrointestinal bleeding

• Tardive dyskinesia

• Renal impairment

• Hepatotoxicity

What is the primary reason for the use of chromatography in pharmaceutical analysis?

• To enhance the solubility of compounds

• To separate and quantify active pharmaceutical ingredients and impurities

• To increase the potency of drugs

• To reduce the side effects of medications