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NPC D.Pharm practice questions

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Question 1Pharmaceutical Sciences

Which pharmacopoeial test is used to determine the uniformity of content of a low-dose tablet formulation?

  1. Content uniformity test Correct answer.
  2. Friability test
  3. Hardness test
  4. Disintegration test

Explanation

The content uniformity test measures the amount of active ingredient in individual dosage units to confirm that each unit contains a dose within the accepted range. It is specifically required for low-dose products where weight variation cannot reliably reflect drug content. Friability, disintegration, and hardness assess physical properties, not the quantity of drug per unit.

Question 2Pharmaceutical Sciences

A prescription is written for 'Amoxicillin 250 mg PO TID'. What does 'TID' direct the pharmacist to do?

  1. Administer the dose every other day
  2. Administer the dose at bedtime
  3. Administer the dose twice daily
  4. Administer the dose three times daily Correct answer.

Explanation

TID is the standard Latin-derived abbreviation for ter in die, meaning three times a day. It specifies the dosing frequency, so the patient receives three doses in each 24-hour period. It does not define route, which is given separately as PO (by mouth).

Question 3Pharmaceutical Sciences

Which route of administration completely bypasses first-pass hepatic metabolism?

  1. Oral capsule
  2. Oral tablet
  3. Intravenous injection Correct answer.
  4. Rectal suppository

Explanation

Drugs given intravenously enter the systemic circulation directly, so they are not exposed to hepatic metabolism before reaching target tissues. Oral dosage forms are absorbed into the portal circulation and undergo first-pass metabolism in the liver. Rectal absorption is partly portal and partly systemic, so it only partially avoids first-pass effects.

Question 4Pharmaceutical Sciences

Which excipient is added to a tablet formulation primarily to promote disintegration of the tablet in the gastrointestinal tract?

  1. Lactose
  2. Magnesium stearate
  3. Croscarmellose sodium Correct answer.
  4. Hydroxypropyl methylcellulose

Explanation

Croscarmellose sodium is a superdisintegrant that swells on contact with water and breaks the tablet into particles, aiding dissolution. Magnesium stearate is a lubricant, lactose is a diluent, and hydroxypropyl methylcellulose is typically a binder or matrix former. The role of each excipient depends on its function in the formulation.

Question 5Pharmaceutical Sciences

Which body is responsible for approving new drug applications for marketing in the United States?

  1. World Health Organization
  2. Food and Drug Administration Correct answer.
  3. United States Pharmacopeia
  4. Drug Enforcement Administration

Explanation

The Food and Drug Administration reviews and approves new drug applications, assessing safety, efficacy, and manufacturing quality before a product can be marketed. The World Health Organization issues guidance but does not approve national marketing applications. The USP sets public standards, and the DEA regulates controlled substances rather than approving new drugs.

Question 6Pharmaceutical Sciences

Which type of reaction is most characteristic of an ester hydrolysis in aqueous solution?

  1. Nucleophilic acyl substitution Correct answer.
  2. Electrophilic aromatic substitution
  3. Pericyclic cycloaddition
  4. Free-radical addition

Explanation

Ester hydrolysis proceeds by nucleophilic attack at the carbonyl carbon, forming a tetrahedral intermediate and then cleaving the acyl-oxygen bond. This is the defining pattern of nucleophilic acyl substitution. Aromatic substitution, radical addition, and cycloaddition involve different substrates and mechanisms.

Question 7Pharmaceutical Sciences

Which microorganism is the standard challenge organism used to test the effectiveness of a sterilization process by moist heat at 121 °C?

  1. Candida albicans yeast
  2. Escherichia coli vegetative cells
  3. Staphylococcus aureus vegetative cells
  4. Geobacillus stearothermophilus spores Correct answer.

Explanation

Geobacillus stearothermophilus spores are highly heat resistant and are used as a biological indicator for moist-heat sterilization. Vegetative bacteria and yeasts are far less resistant and would be killed too readily to provide a meaningful challenge. The use of spores ensures the process achieves a defined sterility assurance level.

Question 8Pharmaceutical Sciences

Which term describes the volume of plasma cleared of drug per unit time?

  1. Clearance Correct answer.
  2. Volume of distribution
  3. Bioavailability
  4. Half-life

Explanation

Clearance is defined as the volume of plasma from which drug is completely removed per unit time, usually expressed in mL/min or L/h. Half-life is the time for plasma concentration to fall by half, volume of distribution relates amount of drug to plasma concentration, and bioavailability describes the fraction of dose reaching systemic circulation.

Question 9Pharmaceutical Sciences

A patient taking warfarin is prescribed a drug that inhibits CYP2C9. What is the most likely clinical consequence?

  1. Reduced warfarin absorption from the gut
  2. Increased INR and bleeding risk Correct answer.
  3. Decreased INR and loss of anticoagulation
  4. No change because warfarin is renally cleared unchanged

Explanation

S-warfarin, the more potent enantiomer, is metabolised mainly by CYP2C9, so inhibition of this enzyme reduces warfarin clearance and raises plasma concentrations. The resulting effect is an elevated INR and greater bleeding risk. Enzyme inhibition does not primarily alter absorption or renal excretion of unchanged drug.

Question 10Pharmaceutical Sciences

A drug has a volume of distribution of 40 L and a clearance of 4 L/h. What is its elimination half-life?

  1. 0.1 hours
  2. 10 hours
  3. 6.9 hours Correct answer.
  4. 160 hours

Explanation

Half-life is calculated as 0.693 multiplied by volume of distribution divided by clearance. Here 0.693 × 40 L ÷ 4 L/h equals approximately 6.9 hours. This relationship shows that half-life lengthens when distribution volume rises or clearance falls.

Question 11Pharmaceutical Sciences

Which formulation strategy is most appropriate for a drug that is extensively degraded in the stomach and poorly absorbed from the colon?

  1. Sublingual tablet
  2. Topical gel applied to the skin
  3. Immediate-release tablet taken with food
  4. Enteric-coated tablet releasing drug in the small intestine Correct answer.

Explanation

An enteric coat resists gastric acid and dissolves at the higher pH of the small intestine, protecting the drug from stomach degradation and releasing it at the main absorptive site. A plain immediate-release tablet would expose the drug to gastric acid. Sublingual and topical routes would not deliver the intended systemic oral therapy for this profile.

Question 12Pharmaceutical Sciences

A 70 kg patient requires a drug dose of 5 mg/kg/day given in two divided doses. How many milligrams should each dose contain?

  1. 700 mg
  2. 175 mg Correct answer.
  3. 350 mg
  4. 87.5 mg

Explanation

The total daily dose is 5 mg/kg × 70 kg, which equals 350 mg per day. Dividing this by two doses gives 175 mg per dose. Checking the arithmetic confirms that two 175 mg doses supply the required 350 mg daily total.

Question 13Pharmaceutical Sciences

Which property of a drug molecule most directly favours passive diffusion across the lipid bilayer of enterocytes?

  1. Large molecular weight above 1000 Da
  2. High degree of ionisation at intestinal pH
  3. High lipophilicity at physiological pH Correct answer.
  4. High aqueous solubility with complete ionisation

Explanation

Passive transcellular diffusion requires the molecule to partition into the lipid membrane, which is favoured by adequate lipophilicity in the unionised form. Ionised species are poorly membrane permeable, and very large molecules are largely excluded from passive diffusion. Aqueous solubility aids dissolution but does not by itself promote membrane permeation.

Question 14Pharmaceutical Sciences

Why is the biuret test unsuitable for detecting a primary amine in a pharmaceutical raw material?

  1. It reacts with peptide bonds rather than free amines Correct answer.
  2. It needs a carbonyl group adjacent to a double bond
  3. It requires an aromatic ring to produce colour
  4. It detects only reducing sugars

Explanation

The biuret reaction depends on coordination of copper ions with peptide bonds, so it is a test for proteins and peptides rather than free primary amines. Aromatic ring requirements and reducing-sugar detection describe other tests such as the xanthoproteic or Fehling tests. Recognising the functional group targeted by each test prevents misidentification.

Question 15Pharmaceutical Sciences

Which factor most strongly increases the risk of microbial contamination of an aqueous oral syrup during storage?

  1. Adjustment of pH to 3.0
  2. Use of a glass container
  3. Presence of a chelating agent
  4. Absence of an effective preservative system Correct answer.

Explanation

Aqueous syrups support microbial growth, so an effective preservative system is essential. Without adequate preservation, contamination during use or storage becomes likely. Low pH and chelating agents may actually inhibit some organisms, and glass containers are inert and do not promote contamination.

Question 16Pharmaceutical Sciences

Which statement best explains why a sustained-release formulation may be inappropriate for a drug with a very short half-life and narrow therapeutic index?

  1. Sustained release always increases the total dose required
  2. The formulation would prevent hepatic metabolism of the drug
  3. The drug would be absorbed too slowly to have any effect
  4. Small fluctuations in release rate could cause toxic or subtherapeutic concentrations Correct answer.

Explanation

For a narrow therapeutic index drug, even modest variability in release or absorption can produce concentrations outside the safe range. A very short half-life demands precise control of input rate, which is difficult to guarantee with a sustained-release matrix. The concern is fluctuation and safety, not a lack of effect or altered metabolism.

Question 17Pharmaceutical Sciences

A pharmacist observes that a drug solution follows first-order degradation with a rate constant of 0.02 per month. What percentage of the initial concentration remains after approximately 35 months?

  1. About 75%
  2. About 50% Correct answer.
  3. About 10%
  4. About 25%

Explanation

For first-order kinetics, the half-life equals 0.693 divided by the rate constant, which is about 34.7 months. Thirty-five months therefore corresponds to roughly one half-life, leaving about 50% of the initial concentration. This relationship underpins shelf-life estimation based on first-order degradation.

Question 18Pharmaceutical Sciences

Which mechanism explains why co-administration of a drug that alkalinises urine increases the renal excretion of salicylate?

  1. Increased ionisation reduces tubular reabsorption Correct answer.
  2. Enhanced hepatic conjugation
  3. Increased glomerular filtration rate
  4. Reduced protein binding in plasma

Explanation

Salicylate is a weak acid, so raising urine pH increases its ionised fraction. Ionised molecules are less able to diffuse back across the tubular epithelium, so more is excreted in urine. This ion-trapping effect is a classic application of urine pH manipulation in overdose management.

Question 19Pharmaceutical Sciences

Which of the following best describes the purpose of a stability-indicating assay in pharmaceutical analysis?

  1. To identify the polymorphic form of the drug
  2. To determine the particle size distribution
  3. To quantify the drug in the presence of its degradation products Correct answer.
  4. To measure tablet hardness after storage

Explanation

A stability-indicating assay is validated to separate and quantify the active ingredient without interference from degradation products or excipients. This allows reliable assessment of potency loss during stability studies. Hardness, polymorphism, and particle size are separate physical characterisations.

Question 20Pharmaceutical Sciences

A new tablet formulation shows acceptable hardness but disintegrates in more than 30 minutes in purified water. Which change is most likely to improve disintegration?

  1. Add a hydrophobic coating
  2. Increase the concentration of croscarmellose sodium Correct answer.
  3. Increase the compression force
  4. Increase the concentration of magnesium stearate

Explanation

Slow disintegration with adequate hardness suggests insufficient wicking and swelling within the tablet matrix. Increasing a superdisintegrant such as croscarmellose sodium promotes water uptake and rapid breakup. More lubricant, higher compression force, or a hydrophobic coat would further retard disintegration.

Question 21Pharmaceutical Sciences

Which statement correctly distinguishes pharmacodynamics from pharmacokinetics?

  1. Pharmacodynamics describes absorption, whereas pharmacokinetics describes receptor binding
  2. Pharmacodynamics describes drug action at the target, whereas pharmacokinetics describes drug disposition Correct answer.
  3. Pharmacodynamics describes metabolism, whereas pharmacokinetics describes excretion
  4. Pharmacodynamics describes formulation, whereas pharmacokinetics describes stability

Explanation

Pharmacodynamics concerns what the drug does to the body, including receptor binding and downstream effects. Pharmacokinetics concerns what the body does to the drug, covering absorption, distribution, metabolism, and excretion. Keeping these domains distinct is essential for interpreting dose-response and concentration-time data.

Question 22Pharmaceutical Sciences

A weakly basic drug with a pKa of 8.4 is formulated as an oral solution at pH 5.4. Which statement best describes its ionisation in the stomach?

  1. It is equally ionised and unionised at any pH
  2. It is predominantly unionised because pH is below its pKa
  3. It is predominantly ionised because pH is well below its pKa Correct answer.
  4. It is completely unionised regardless of pH

Explanation

For a weak base, the fraction ionised increases as pH falls below the pKa. At pH 5.4, three units below the pKa of 8.4, the protonated ionised form predominates overwhelmingly. This reduces gastric absorption of the base while favouring dissolution as a soluble salt.

Question 23Pharmaceutical Sciences

Which analytical technique is most appropriate for quantifying a drug at trace levels in a biological matrix with high selectivity?

  1. Liquid chromatography coupled with tandem mass spectrometry Correct answer.
  2. Thin-layer chromatography with visual inspection
  3. Ultraviolet-visible spectrophotometry
  4. Karl Fischer titration

Explanation

LC-MS/MS combines chromatographic separation with mass-specific detection, giving the sensitivity and selectivity needed for trace quantification in complex biological matrices. UV spectrophotometry lacks selectivity in the presence of co-eluting interferences, and TLC is semiquantitative at best. Karl Fischer titration measures water content, not drug concentration.

Question 24Pharmaceutical Sciences

A drug is 90% bound to plasma albumin. If albumin binding is displaced by a co-administered drug, what is the immediate effect on the unbound fraction?

  1. The unbound fraction increases from 10% to a higher value Correct answer.
  2. The unbound fraction becomes zero
  3. The unbound fraction decreases below 10%
  4. The unbound fraction remains exactly 10%

Explanation

The unbound fraction equals one minus the bound fraction, so 90% binding leaves 10% free. Displacement reduces the bound proportion and therefore raises the unbound fraction above 10%. The transient rise in free drug can increase pharmacological effect and toxicity before redistribution and clearance restore equilibrium.

Question 25Pharmaceutical Sciences

A manufacturer needs to demonstrate that a cleaning procedure reliably removes a highly potent active ingredient from shared equipment. Which approach best supports this validation?

  1. Recording the cleaning time in the batch record
  2. Swab sampling of worst-case locations with a validated specific analytical method Correct answer.
  3. Visual inspection alone after each batch
  4. Measuring total organic carbon only in the final rinse

Explanation

Cleaning validation for potent actives requires sampling worst-case areas and quantifying residues with a method validated for sensitivity and specificity. Swab sampling recovers residue from defined surface areas and allows comparison with a health-based limit. Visual inspection, TOC alone, and documentation do not demonstrate removal of a specific active at trace levels.

Question 26Pharmaceutical Sciences

Which type of pharmaceutical incompatibility is demonstrated when a cationic surfactant reacts with an anionic surfactant to form an insoluble complex?

  1. Physical incompatibility Correct answer.
  2. Therapeutic incompatibility
  3. Chemical incompatibility
  4. Pharmacological incompatibility

Explanation

The reaction between oppositely charged surfactants produces a visible precipitate or phase separation, which is a physical incompatibility because it alters the physical appearance and homogeneity of the preparation. Chemical incompatibility would involve a change in molecular structure, while therapeutic and pharmacological incompatibilities refer to altered clinical effects.

Question 27Pharmaceutical Sciences

Which statement best describes the mechanism of action of a non-competitive antagonist at a receptor?

  1. It binds to the receptor and increases the potency of the agonist.
  2. It binds to an allosteric site and reduces the maximal response without affecting the agonist's affinity. Correct answer.
  3. It binds to plasma proteins and reduces the free concentration of the agonist.
  4. It binds to the same site as the agonist and can be overcome by increasing the agonist concentration.

Explanation

A non-competitive antagonist binds at a site distinct from the agonist binding site and produces an insurmountable reduction in the maximal response. It does not compete with the agonist for the orthosteric site, so increasing agonist concentration cannot fully restore the response. This is distinct from competitive antagonism, which can be overcome by higher agonist concentrations.

Question 28Pharmaceutical Sciences

Which factor is most important in determining the rate of drug absorption from an intramuscular injection site?

  1. The osmolality of the formulation
  2. The volume of the injection
  3. Blood flow to the injection site Correct answer.
  4. The pH of the formulation

Explanation

Absorption from an intramuscular site depends largely on the rate of blood flow to the muscle, which removes the drug from the injection depot. Increased blood flow, such as during exercise or with vasodilators, generally accelerates absorption. Formulation factors such as pH and osmolality may affect tolerability but are less critical for absorption rate.

Question 29Pharmaceutical Sciences

Which excipient is added to a tablet formulation primarily to promote the breakup of the tablet into smaller particles in the gastrointestinal tract?

  1. Binder
  2. Glidant
  3. Disintegrant Correct answer.
  4. Lubricant

Explanation

Disintegrants are included to facilitate the break-up of the tablet into granules and particles upon contact with aqueous fluids, thereby increasing the surface area for dissolution. Binders provide cohesion, lubricants prevent sticking to punches and dies, and glidants improve powder flow.

Question 30Pharmaceutical Sciences

Which condition is required for a drug to be absorbed by passive diffusion across the gastrointestinal epithelium?

  1. The drug must be ionized at the absorption site.
  2. The drug must be bound to plasma proteins.
  3. The drug must be unionized and sufficiently lipid soluble. Correct answer.
  4. The drug must be actively transported by a carrier protein.

Explanation

Passive diffusion across lipid membranes requires the drug to be in its unionized, lipophilic form, as charged species are poorly permeable. The pH of the absorption site relative to the drug's pKa determines the fraction unionized. Active transport and protein binding are separate processes.

Question 31Pharmaceutical Sciences

Which statement best explains why a drug with a high hepatic extraction ratio has low oral bioavailability?

  1. It is poorly absorbed from the gastrointestinal tract.
  2. It is rapidly excreted unchanged by the kidneys.
  3. It binds extensively to plasma proteins.
  4. It undergoes extensive first-pass metabolism in the liver. Correct answer.

Explanation

A drug with a high hepatic extraction ratio is efficiently removed from portal blood during its first pass through the liver, so a large fraction of an oral dose is metabolized before reaching systemic circulation. This first-pass effect reduces oral bioavailability. High plasma protein binding and renal excretion do not directly cause low oral bioavailability.

Question 32Pharmaceutical Sciences

Which type of drug interaction is involved when probenecid increases the plasma concentration of penicillin by competing for renal tubular secretion?

  1. Pharmacodynamic interaction
  2. Pharmaceutical incompatibility
  3. Pharmacokinetic interaction Correct answer.
  4. Idiosyncratic reaction

Explanation

Probenecid competes with penicillin for the organic anion transporter in the renal tubule, reducing penicillin's renal clearance and increasing its plasma concentration. This is a pharmacokinetic interaction because it alters the absorption, distribution, metabolism, or excretion of the drug. Pharmacodynamic interactions involve effects at the site of action.

Question 33Pharmaceutical Sciences

Which analytical method is based on the measurement of the wavelength and intensity of light emitted by atoms excited in a flame or plasma?

  1. Atomic emission spectroscopy Correct answer.
  2. Atomic absorption spectroscopy
  3. Infrared spectroscopy
  4. UV-visible spectrophotometry

Explanation

Atomic emission spectroscopy measures the light emitted by atoms that have been excited by a flame or plasma and then return to lower energy levels. Atomic absorption spectroscopy, in contrast, measures the absorption of light by ground-state atoms. UV-visible and infrared spectroscopy involve molecular absorption.

Question 34Pharmaceutical Sciences

Which statement best describes the role of a internal standard in a chromatographic bioanalytical method?

  1. It corrects for variability in sample preparation and injection volume. Correct answer.
  2. It acts as a calibration standard for the detector.
  3. It suppresses ionization of the analyte in mass spectrometry.
  4. It increases the retention time of the analyte.

Explanation

An internal standard is a compound added in constant amount to all samples and standards to correct for variations in sample preparation, injection volume, and detector response. It is chosen to be chemically similar to the analyte but distinguishable. It does not alter retention time, suppress ionization, or serve as a calibration standard.

Question 35Pharmaceutical Sciences

Which step in the wet granulation process is most critical for ensuring uniform distribution of a low-dose active ingredient?

  1. Dry mixing of the active ingredient with excipients before granulation Correct answer.
  2. Compression of the granules into tablets
  3. Sizing the dried granules
  4. Mixing the active ingredient with the binder solution

Explanation

For a low-dose active ingredient, uniform distribution is achieved during the dry mixing stage with excipients before any liquid is added. Inadequate dry mixing can lead to content uniformity problems that cannot be corrected later. Binder addition, granule sizing, and compression occur after the drug has been distributed.

Question 36Pharmaceutical Sciences

Which factor most directly determines the osmolality of a parenteral solution?

  1. The pH of the solution
  2. The number of particles dissolved in the solution Correct answer.
  3. The molecular weight of the drug
  4. The viscosity of the solution

Explanation

Osmolality is a colligative property that depends on the number of dissolved particles per unit mass of solvent, not on their size or identity. Molecular weight, pH, and viscosity do not directly determine osmolality. Therefore, the total particle concentration is the key factor.

Question 37Pharmaceutical Sciences

Which statement best explains why a drug with a narrow therapeutic index requires therapeutic drug monitoring?

  1. Small changes in plasma concentration can lead to therapeutic failure or toxicity. Correct answer.
  2. The drug is extensively bound to plasma proteins.
  3. The drug is rapidly eliminated from the body.
  4. The drug has a large volume of distribution.

Explanation

A narrow therapeutic index means the difference between the minimum effective concentration and the minimum toxic concentration is small. Therefore, small variations in plasma concentration can result in either lack of efficacy or adverse effects, making monitoring essential. Rapid elimination, protein binding, and large volume of distribution can influence dosing but are not the defining reason for monitoring.

Question 38Pharmaceutical Sciences

Which type of emulsion is formed when water is dispersed as droplets in an oil continuous phase?

  1. Water-in-oil emulsion Correct answer.
  2. Microemulsion
  3. Multiple emulsion
  4. Oil-in-water emulsion

Explanation

A water-in-oil emulsion consists of water droplets dispersed in a continuous oil phase. This is the opposite of an oil-in-water emulsion, where oil droplets are dispersed in water. Microemulsions and multiple emulsions are different structural types.

Question 39Pharmaceutical Sciences

Which statement best explains why a drug that is a substrate for P-glycoprotein may have limited oral bioavailability?

  1. P-glycoprotein enhances the absorption of the drug in the intestine.
  2. P-glycoprotein increases the metabolic breakdown of the drug in the liver.
  3. P-glycoprotein increases renal excretion of the drug.
  4. P-glycoprotein effluxes the drug back into the intestinal lumen, reducing absorption. Correct answer.

Explanation

P-glycoprotein is an efflux transporter located on the apical membrane of enterocytes. It pumps substrate drugs from the intestinal cells back into the lumen, thereby reducing the fraction absorbed. It does not enhance absorption, metabolize drugs, or directly increase renal excretion.

Question 40Pharmaceutical Sciences

Which factor is most important for ensuring the stability of an emulsion during long-term storage?

  1. The method of shaking before use
  2. The color of the container
  3. The choice of emulsifying agent and its concentration Correct answer.
  4. The pH of the aqueous phase alone

Explanation

The emulsifying agent forms a film at the oil-water interface and provides a barrier to coalescence; its type and concentration are critical for long-term stability. Container color, pH alone, and shaking before use may influence stability or use but are secondary to the emulsifier system.

Question 41Pharmacology and Therapeutics

A patient with a documented penicillin allergy develops a severe respiratory infection. Which antibiotic class should be avoided because of potential cross-reactivity with penicillin?

  1. Aminoglycosides
  2. Carbapenems Correct answer.
  3. Macrolides
  4. Glycopeptides

Explanation

Carbapenems share the beta-lactam ring structure with penicillins, so patients with penicillin allergy carry a modest risk of cross-reactivity and these agents are used cautiously. Aminoglycosides, glycopeptides, and macrolides have unrelated structures and are not cross-reactive with penicillin.

Question 42Pharmacology and Therapeutics

Which mechanism best describes the antihypertensive action of enalapril?

  1. Blockade of voltage-gated calcium channels
  2. Blockade of angiotensin II AT1 receptors
  3. Inhibition of angiotensin-converting enzyme Correct answer.
  4. Direct inhibition of renin release

Explanation

Enalapril is an ACE inhibitor that prevents conversion of angiotensin I to angiotensin II and reduces bradykinin breakdown. This lowers vasoconstriction and aldosterone secretion, reducing blood pressure.

Question 43Pharmacology and Therapeutics

A patient started on isoniazid for tuberculosis should receive which vitamin supplement to prevent peripheral neuropathy?

  1. Cyanocobalamin
  2. Thiamine
  3. Riboflavin
  4. Pyridoxine Correct answer.

Explanation

Isoniazid interferes with pyridoxine metabolism and can cause peripheral neuropathy, so pyridoxine (vitamin B6) is co-prescribed as prophylaxis. This is especially important in malnourished patients, pregnant women, and those with diabetes or HIV.

Question 44Pharmacology and Therapeutics

Which adverse effect is most characteristic of long-term systemic corticosteroid therapy?

  1. Bradycardia and bronchospasm
  2. Cushingoid features and osteoporosis Correct answer.
  3. Hyperkalemia and weight loss
  4. Hypoglycemia and hypotension

Explanation

Prolonged glucocorticoid exposure produces iatrogenic Cushing syndrome with central obesity, moon face, and bone loss leading to osteoporosis. Patients on long-term therapy need monitoring of bone density, glucose, and blood pressure.

Question 45Pharmacology and Therapeutics

A patient taking warfarin is started on a drug that inhibits CYP2C9. What is the most appropriate initial action?

  1. Add aspirin for additional anticoagulation
  2. Switch warfarin to once-weekly dosing
  3. Monitor INR closely and consider dose reduction Correct answer.
  4. Increase the warfarin dose empirically

Explanation

Warfarin is metabolized mainly by CYP2C9, so inhibitors such as amiodarone or metronidazole reduce clearance and raise INR and bleeding risk. Close INR monitoring with possible dose reduction is the safe response.

Question 46Pharmacology and Therapeutics

Which laboratory parameter should be monitored for a patient on long-term amiodarone therapy?

  1. Serum potassium only
  2. Thyroid function and liver enzymes Correct answer.
  3. Serum amylase
  4. Serum iron

Explanation

Amiodarone accumulates in tissue and can cause thyroid dysfunction (both hypo- and hyperthyroidism) and hepatotoxicity, so thyroid function tests and liver enzymes are monitored periodically. Pulmonary and ocular toxicity also warrant surveillance.

Question 47Pharmacology and Therapeutics

A patient presents with pinpoint pupils, respiratory depression, and decreased consciousness. Which antidote is indicated?

  1. Flumazenil
  2. Naloxone Correct answer.
  3. Atropine
  4. N-acetylcysteine

Explanation

The triad of miosis, respiratory depression, and coma indicates opioid overdose, and naloxone is a competitive opioid receptor antagonist that rapidly reverses these effects. Repeat dosing may be needed because naloxone has a shorter half-life than many opioids.

Question 48Pharmacology and Therapeutics

Which statement about metformin is correct?

  1. It reduces hepatic gluconeogenesis and improves insulin sensitivity Correct answer.
  2. It is the preferred first-line agent in advanced renal failure
  3. It causes weight gain and hypoglycemia
  4. It stimulates pancreatic insulin secretion

Explanation

Metformin works mainly by reducing hepatic glucose production and improving peripheral insulin sensitivity. It does not stimulate insulin release, so it rarely causes hypoglycemia when used alone and is weight-neutral.

Question 49Pharmacology and Therapeutics

A patient on furosemide develops muscle weakness and ECG changes. Which electrolyte disturbance is most likely?

  1. Hypernatremia
  2. Hyperkalemia
  3. Hypokalemia Correct answer.
  4. Hypercalcemia

Explanation

Loop diuretics inhibit the Na-K-2Cl cotransporter in the thick ascending limb, increasing potassium excretion. Hypokalemia causes muscle weakness and ECG changes such as flattened T waves and U waves.

Question 50Pharmacology and Therapeutics

Which drug is a selective beta-1 adrenergic blocker used to reduce mortality after myocardial infarction?

  1. Propranolol
  2. Metoprolol Correct answer.
  3. Phentolamine
  4. Prazosin

Explanation

Metoprolol is a cardioselective beta-1 blocker that reduces myocardial oxygen demand and improves survival post-MI. Beta-1 selectivity also limits bronchospasm risk compared with nonselective agents.