Anti-inflammatory agents – Mefenamic acid MCQs With Answer

Anti-inflammatory agents – Mefenamic acid MCQs With Answer

Mefenamic acid is a fenamate class nonsteroidal anti-inflammatory drug (NSAID) widely studied by B.Pharm students for its analgesic, anti-inflammatory and antipyretic actions. This concise, exam-focused introduction covers mechanism of action, pharmacokinetics, clinical uses (notably dysmenorrhea), adverse effects, contraindications, drug interactions and dosage considerations. Key terms to remember include mefenamic acid, NSAID, anthranilic acid derivative, COX inhibition, hepatic metabolism, GI toxicity and renal effects. These MCQs will deepen your understanding of therapeutic rationale, monitoring parameters and safe dispensing practices for mefenamic acid in clinical pharmacy. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which chemical class does mefenamic acid belong to?

• Salicylates
• Fenamates (anthranilic acid derivatives)
• Propionic acid derivatives
• Oxicam class

Correct Answer: Fenamates (anthranilic acid derivatives)

Q2. The primary mechanism of action of mefenamic acid is:

• Selective COX-2 inhibition
• Irreversible acetylation of COX enzymes
• Competitive reversible inhibition of cyclooxygenase (COX) enzymes
• Activation of opioid receptors

Correct Answer: Competitive reversible inhibition of cyclooxygenase (COX) enzymes

Q3. Which clinical indication is mefenamic acid commonly used for?

• Chronic heart failure
• Primary dysmenorrhea and short-term pain relief
• Antibacterial therapy
• Long-term anticoagulation

Correct Answer: Primary dysmenorrhea and short-term pain relief

Q4. Mefenamic acid is best described pharmacokinetically as:

• Poorly absorbed orally and primarily excreted unchanged in feces
• Well absorbed orally, highly protein bound, and extensively hepatic metabolized
• Administered only by intravenous route due to poor oral bioavailability
• Excreted mainly via the lungs as volatile metabolites

Correct Answer: Well absorbed orally, highly protein bound, and extensively hepatic metabolized

Q5. A common adverse effect of mefenamic acid is:

• Hyperkalemia without renal involvement
• Gastrointestinal irritation and risk of peptic ulcer/bleeding
• Marked hypoglycemia
• Permanent alopecia

Correct Answer: Gastrointestinal irritation and risk of peptic ulcer/bleeding

Q6. Which statement about mefenamic acid’s COX selectivity is correct?

• It is a highly selective COX-2 inhibitor with minimal GI risk
• It selectively inhibits COX-1 only
• It is a nonselective COX inhibitor affecting both COX-1 and COX-2
• It does not affect COX enzymes; acts via leukotriene inhibition

Correct Answer: It is a nonselective COX inhibitor affecting both COX-1 and COX-2

Q7. Which of the following is a serious contraindication for mefenamic acid use?

• Controlled hypertension on monotherapy
• Known hypersensitivity to other NSAIDs or aspirin
• History of seasonal allergic rhinitis only
• Mild, well-controlled asthma with no NSAID sensitivity

Correct Answer: Known hypersensitivity to other NSAIDs or aspirin

Q8. Regarding pregnancy, mefenamic acid is:

• Safe throughout pregnancy including third trimester
• Contraindicated in the third trimester due to risk of premature ductus arteriosus closure
• Recommended as the first-line analgesic in pregnancy
• Used to induce labor due to uterotonic effects

Correct Answer: Contraindicated in the third trimester due to risk of premature ductus arteriosus closure

Q9. Typical adult dosing regimen commonly recommended for mefenamic acid in acute pain is:

• 500 mg initial then 250 mg every 6 hours, maximum 1 g/day
• 50 mg once daily
• 2 g twice daily indefinitely
• Only single-dose administration allowed

Correct Answer: 500 mg initial then 250 mg every 6 hours, maximum 1 g/day

Q10. Mefenamic acid’s elimination half-life is approximately:

• 48–72 hours
• 1–2 hours
• 2–4 weeks
• 10–14 minutes

Correct Answer: 1–2 hours

Q11. Which laboratory parameter may be elevated or affected by NSAID therapy including mefenamic acid?

• Serum amylase only
• Prothrombin time/INR due to interaction with warfarin
• Hemoglobin A1c directly
• Serum sodium via direct stimulation of ADH

Correct Answer: Prothrombin time/INR due to interaction with warfarin

Q12. A key counseling point for patients prescribed mefenamic acid is:

• Take with a high-fat meal to increase absorption significantly
• Avoid concurrent use of alcohol and report any black tarry stools or severe abdominal pain
• It enhances anticoagulant effect of vitamin K supplements and is safe to use with warfarin without monitoring
• No interactions exist, so no monitoring is required

Correct Answer: Avoid concurrent use of alcohol and report any black tarry stools or severe abdominal pain

Q13. The structural feature that defines fenamates like mefenamic acid is:

• A salicylic acid backbone
• An anthranilic acid (o-aminobenzoic acid) derivative core
• A central pyrazolone ring
• A barbiturate moiety

Correct Answer: An anthranilic acid (o-aminobenzoic acid) derivative core

Q14. Which adverse renal effect can NSAIDs including mefenamic acid precipitate?

• Renal papillary necrosis and acute kidney injury due to reduced prostaglandin-mediated renal blood flow
• Nephrogenic diabetes insipidus exclusively
• Direct tubular cytotoxicity leading to permanent renal failure in all patients
• Increased glomerular filtration rate (GFR) leading to hyperfiltration

Correct Answer: Renal papillary necrosis and acute kidney injury due to reduced prostaglandin-mediated renal blood flow

Q15. Which drug interaction with mefenamic acid can increase the risk of lithium toxicity?

• Concurrent use of ACE inhibitors only
• Concurrent use of diuretics like thiazides is unrelated
• Concomitant use of lithium can raise lithium plasma levels due to reduced renal clearance
• Use with proton pump inhibitors increases lithium clearance

Correct Answer: Concomitant use of lithium can raise lithium plasma levels due to reduced renal clearance

Q16. In overdose management of mefenamic acid, an appropriate early intervention is:

• Whole bowel irrigation only
• Administration of activated charcoal if presented early
• Immediate dialysis as the first-line step in all cases
• No treatment is necessary because it is non-toxic in large doses

Correct Answer: Administration of activated charcoal if presented early

Q17. Which CNS adverse effect is most commonly associated with mefenamic acid?

• Severe peripheral neuropathy in all patients
• Dizziness, headache and rarely aseptic meningitis or seizures
• Permanent cognitive decline within days
• Increased seizure threshold universally

Correct Answer: Dizziness, headache and rarely aseptic meningitis or seizures

Q18. Which laboratory test would you monitor in long-term NSAID therapy to detect occult adverse effects?

• Liver function tests, renal function (serum creatinine) and complete blood count
• Urine pregnancy test only
• Fasting blood glucose exclusively
• Serum amylase weekly

Correct Answer: Liver function tests, renal function (serum creatinine) and complete blood count

Q19. Which of the following best describes mefenamic acid’s protein binding?

• Negligible protein binding (0–5%)
• Moderate to high protein binding (~90%)
• Protein binding is irrelevant for mefenamic acid
• It binds only to albumin in neonates

Correct Answer: Moderate to high protein binding (~90%)

Q20. Combining mefenamic acid with which class of drugs increases the risk of gastrointestinal bleeding?

• Proton pump inhibitors
• Selective serotonin reuptake inhibitors (SSRIs) and anticoagulants
• Topical emollients
• Beta blockers

Correct Answer: Selective serotonin reuptake inhibitors (SSRIs) and anticoagulants

Q21. Which hepatic consideration is relevant for prescribing mefenamic acid?

• No hepatic metabolism; safe in liver failure without dose change
• Hepatic metabolism predominates; use caution in severe hepatic impairment
• It is produced by the liver and therefore contraindicated in hepatitis A only
• It enhances hepatic regeneration

Correct Answer: Hepatic metabolism predominates; use caution in severe hepatic impairment

Q22. Which statement about mefenamic acid formulations is correct?

• Available primarily as oral tablets and capsules; IV formulation is commonly used
• Commonly formulated as oral tablets and capsules; parenteral forms are not widely used
• Only available as transdermal patches
• Available exclusively as inhalation therapy

Correct Answer: Commonly formulated as oral tablets and capsules; parenteral forms are not widely used

Q23. The effect of mefenamic acid on platelet function is due to:

• Enhancement of thromboxane A2 production
• Reversible inhibition of platelet COX-derived thromboxane synthesis leading to impaired aggregation
• Direct platelet destruction in bone marrow
• Selective inhibition of platelet ADP receptors

Correct Answer: Reversible inhibition of platelet COX-derived thromboxane synthesis leading to impaired aggregation

Q24. An important counseling point for older patients taking mefenamic acid is:

• They have lower GI and renal risks than young adults
• Use with caution due to increased risk of renal impairment, GI bleeding and cardiovascular events
• No dose adjustment needed regardless of comorbidities
• They should take it with a large glass of grapefruit juice daily

Correct Answer: Use with caution due to increased risk of renal impairment, GI bleeding and cardiovascular events

Q25. Which clinical sign would most suggest an NSAID-induced hypersensitivity reaction?

• Gradual weight gain over months
• Bronchospasm, urticaria or angioedema shortly after NSAID intake
• Isolated hair loss only
• Chronic dry eyes without other symptoms

Correct Answer: Bronchospasm, urticaria or angioedema shortly after NSAID intake

Q26. Mefenamic acid is least appropriate for long-term management of which condition?

• Short-term acute musculoskeletal pain
• Chronic osteoarthritis where safer long-term alternatives are preferred
• Primary dysmenorrhea for short courses
• Single-dose postoperative pain

Correct Answer: Chronic osteoarthritis where safer long-term alternatives are preferred

Q27. Which enzyme system primarily handles the metabolism of mefenamic acid?

• Renal CYP450 exclusively
• Hepatic conjugation and CYP-mediated pathways followed by renal excretion of metabolites
• Metabolized by gut bacteria only
• Not metabolized; excreted unchanged via bile

Correct Answer: Hepatic conjugation and CYP-mediated pathways followed by renal excretion of metabolites

Q28. Which adverse hematologic effect has been reported with mefenamic acid and requires monitoring?

• Severe sustained leukocytosis in all patients
• Aplastic anemia and other blood dyscrasias (rare but serious)
• Immediate polycythemia upon first dose
• Permanent thrombocytosis in children only

Correct Answer: Aplastic anemia and other blood dyscrasias (rare but serious)

Q29. Which of the following describes a drug interaction between mefenamic acid and ACE inhibitors?

• Mefenamic acid potentiates ACE inhibitor effects leading to hypotension
• NSAIDs like mefenamic acid can reduce the antihypertensive effect of ACE inhibitors and increase risk of renal dysfunction
• ACE inhibitors always protect kidneys from NSAID effects
• No interactions exist between NSAIDs and ACE inhibitors

Correct Answer: NSAIDs like mefenamic acid can reduce the antihypertensive effect of ACE inhibitors and increase risk of renal dysfunction

Q30. Which symptom would most likely suggest NSAID-induced renal impairment?

• Polyuria with very low serum creatinine
• Oliguria, rising serum creatinine and peripheral edema
• Increased appetite and weight loss
• Improved urine output and lower blood pressure

Correct Answer: Oliguria, rising serum creatinine and peripheral edema

Q31. Which patient population should generally avoid mefenamic acid?

• Patients in the third trimester of pregnancy
• Healthy adults with no comorbidities
• Patients with seasonal allergies only
• Patients using topical moisturizers

Correct Answer: Patients in the third trimester of pregnancy

Q32. Which monitoring parameter is most relevant when mefenamic acid is used concomitantly with warfarin?

• Serum potassium only
• International Normalized Ratio (INR) and signs of bleeding
• Serum calcium concentration
• Thyroid stimulating hormone (TSH)

Correct Answer: International Normalized Ratio (INR) and signs of bleeding

Q33. Which of these is a pharmacodynamic property of mefenamic acid relevant to its analgesic action?

• Inhibition of prostaglandin synthesis reduces peripheral sensitization of nociceptors
• Stimulation of bradykinin production to reduce pain
• Blockade of voltage-gated sodium channels like local anesthetics
• Activation of NMDA receptors

Correct Answer: Inhibition of prostaglandin synthesis reduces peripheral sensitization of nociceptors

Q34. In patients with peptic ulcer disease, mefenamic acid should be:

• Used freely as it promotes ulcer healing
• Avoided or used with gastroprotective measures if strictly necessary
• Combined with aspirin to reduce ulcer risk
• Given at double the normal dose to overcome gastric acidity

Correct Answer: Avoided or used with gastroprotective measures if strictly necessary

Q35. Which formulation advice is appropriate when dispensing mefenamic acid tablets?

• Advise taking on an empty stomach only to increase GI side effects
• Recommend taking with food or milk to reduce gastrointestinal irritation
• Instruct patients to pulverize and inhale the tablet powder
• Tell patients to avoid all fluids when taking the tablet

Correct Answer: Recommend taking with food or milk to reduce gastrointestinal irritation

Q36. Compared to ibuprofen, mefenamic acid is best characterized as:

• Structurally a propionic acid derivative like ibuprofen
• A fenamate with similar NSAID effects but different chemical structure and adverse effect profile
• An opioid analgesic unrelated to NSAIDs
• A selective COX-2 inhibitor superior in GI safety

Correct Answer: A fenamate with similar NSAID effects but different chemical structure and adverse effect profile

Q37. If a patient reports a history of NSAID-exacerbated respiratory disease (NERD), prescribing mefenamic acid is:

• Safe without precautions
• Contraindicated due to risk of bronchospasm
• Recommended as first-line therapy to treat asthma
• Helpful in preventing respiratory symptoms

Correct Answer: Contraindicated due to risk of bronchospasm

Q38. Which statement about mefenamic acid and breastfeeding is correct?

• Secreted into breast milk; use with caution and consider alternatives in nursing mothers
• Never secreted into breast milk and entirely safe during breastfeeding
• Promotes lactation and is recommended postpartum
• Causes immediate cessation of milk production

Correct Answer: Secreted into breast milk; use with caution and consider alternatives in nursing mothers

Q39. The role of prostaglandin inhibition in the kidneys by NSAIDs leads to which outcome?

• Increased renal perfusion due to vasodilation
• Reduced renal blood flow and potential sodium/water retention due to vasoconstriction of afferent arteriole
• Direct antimicrobial renal protection
• Complete protection against contrast nephropathy

Correct Answer: Reduced renal blood flow and potential sodium/water retention due to vasoconstriction of afferent arteriole

Q40. Which adverse dermatologic reaction can occur with mefenamic acid?

• Severe cutaneous reactions such as Stevens-Johnson syndrome (rare)
• Guaranteed permanent tan after first dose
• Instantaneous hair color change
• Universal protection from sunburn

Correct Answer: Severe cutaneous reactions such as Stevens-Johnson syndrome (rare)

Q41. Which monitoring advice is most appropriate when initiating mefenamic acid in a hypertensive patient?

• No monitoring; NSAIDs lower blood pressure
• Monitor blood pressure and renal function because NSAIDs may raise BP and reduce renal perfusion
• Stop all antihypertensive drugs preemptively
• Only monitor heart rate, not blood pressure

Correct Answer: Monitor blood pressure and renal function because NSAIDs may raise BP and reduce renal perfusion

Q42. Which of the following best explains why NSAIDs can reduce the efficacy of antihypertensive drugs?

• NSAIDs increase prostaglandin synthesis boosting antihypertensive effects
• NSAIDs inhibit renal prostaglandin production leading to sodium retention and reduced response to ACE inhibitors/diuretics
• NSAIDs act as direct vasodilators that interfere with antihypertensives
• NSAIDs block adrenergic receptors enhancing antihypertensive action

Correct Answer: NSAIDs inhibit renal prostaglandin production leading to sodium retention and reduced response to ACE inhibitors/diuretics

Q43. Which counseling point is important regarding duration of therapy with mefenamic acid?

• Prolonged continuous use is preferred for chronic conditions without review
• Use the lowest effective dose for the shortest duration necessary to limit adverse effects
• High-dose long-term therapy is safe in all patients
• Duration does not affect risk profile

Correct Answer: Use the lowest effective dose for the shortest duration necessary to limit adverse effects

Q44. Which adverse cardiovascular risk is associated with NSAID use including mefenamic acid?

• Guaranteed myocardial protection in all patients
• Potentially increased risk of thrombotic events, myocardial infarction or stroke with long-term use
• Instant reversal of atherosclerosis
• Complete prevention of hypertension

Correct Answer: Potentially increased risk of thrombotic events, myocardial infarction or stroke with long-term use

Q45. Which of the following drugs may have increased plasma concentration when co-administered with mefenamic acid due to displacement from plasma proteins?

• Propranolol only
• Warfarin due to high protein binding leading to increased free fraction and bleeding risk
• Insulin injected subcutaneously
• Vitamin C supplements only

Correct Answer: Warfarin due to high protein binding leading to increased free fraction and bleeding risk

Q46. Which biochemical mediator’s synthesis is directly reduced by mefenamic acid leading to anti-inflammatory effects?

• Histamine only
• Prostaglandins synthesized by cyclooxygenase enzymes
• Serotonin exclusively
• All cytokines permanently

Correct Answer: Prostaglandins synthesized by cyclooxygenase enzymes

Q47. In a patient with chronic kidney disease (CKD), prescribing mefenamic acid requires:

• No special precautions; CKD protects against NSAID toxicity
• Extreme caution or avoidance due to risk of further renal impairment and fluid retention
• Doubling the dose to overcome reduced renal function
• Replacement with high-dose acetaminophen without consideration

Correct Answer: Extreme caution or avoidance due to risk of further renal impairment and fluid retention

Q48. Which symptom constellation suggests mefenamic acid-induced hepatic dysfunction?

• Jaundice, dark urine and elevated liver enzymes
• Improved appetite and lowered transaminases
• Sudden increase in visual acuity
• Only ear itching without systemic signs

Correct Answer: Jaundice, dark urine and elevated liver enzymes

Q49. For exam-focused pharmacology, which statement about mefenamic acid’s therapeutic index is most appropriate?

• It has an unlimited therapeutic index; overdoses are benign
• It has a narrow to moderate therapeutic index; attention to dosing and patient factors is essential
• Therapeutic index is irrelevant for NSAIDs
• It is safer than paracetamol in all overdose scenarios

Correct Answer: It has a narrow to moderate therapeutic index; attention to dosing and patient factors is essential

Q50. Which practical dispensing instruction should a B.Pharm student give with mefenamic acid?

• Advise immediate discontinuation only if no effect is felt within 30 minutes
• Explain indication, dose schedule, take with food, warn about GI/renal risks and advise to seek medical help for severe adverse effects
• Recommend doubling the dose if pain persists after one hour
• Tell patient to store tablets in the freezer to increase stability

Correct Answer: Explain indication, dose schedule, take with food, warn about GI/renal risks and advise to seek medical help for severe adverse effects

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