Antacids: Ideal properties MCQs With Answer

Antacids: Ideal properties MCQs With Answer is a focused study resource for B. Pharm students studying antacid pharmacology and formulation. This introduction and question set emphasize ideal properties — rapid onset, sufficient acid neutralization, sustained duration, minimal systemic absorption, non-reactivity with other drugs, palatability, and chemical stability. Understanding acid neutralizing capacity, buffering action, titratable acidity, and common antacid agents (magnesium, aluminium, calcium, sodium salts) is essential for safe prescribing and formulation design. These MCQs cover mechanism of action, formulation considerations, clinical effects, adverse reactions, and drug interactions to strengthen your pharmacological reasoning and exam readiness. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which property is most essential for an ideal antacid to provide immediate symptom relief?

• High systemic absorption
• Rapid onset of action
• Strong chelating ability
• Prolonged enterohepatic recirculation

Correct Answer: Rapid onset of action

Q2. Which characteristic describes a desirable antacid with minimal systemic side effects?

• Highly absorbable ionic form
• Non-absorbable or poorly absorbed compound
• Strong metabolic activation in liver
• High protein binding

Correct Answer: Non-absorbable or poorly absorbed compound

Q3. Titratable acidity in antacid evaluation measures:

• The pH after neutralization
• The amount of base required to raise pH to a defined value
• Systemic alkalosis potential
• The diffusion rate through gastric mucosa

Correct Answer: The amount of base required to raise pH to a defined value

Q4. Acid neutralizing capacity (ANC) primarily indicates:

• The speed of neutralization
• The total amount of acid neutralized per unit dose
• The rate of gastric emptying
• The anti-secretory effect on parietal cells

Correct Answer: The total amount of acid neutralized per unit dose

Q5. Which antacid is most associated with causing constipation?

• Magnesium hydroxide
• Aluminium hydroxide
• Sodium bicarbonate
• Simethicone

Correct Answer: Aluminium hydroxide

Q6. Which antacid commonly causes diarrhea as a side effect?

• Aluminium hydroxide
• Calcium carbonate
• Magnesium hydroxide
• Sucralfate

Correct Answer: Magnesium hydroxide

Q7. Milk-alkali syndrome is most commonly associated with excessive use of:

• Aluminium hydroxide
• Magnesium hydroxide
• Calcium carbonate
• Simethicone

Correct Answer: Calcium carbonate

Q8. Which antacid has the fastest chemical neutralization of gastric acid?

• Aluminium hydroxide
• Calcium carbonate
• Sodium bicarbonate
• Magnesium hydroxide

Correct Answer: Sodium bicarbonate

Q9. An important ideal property to minimize drug interactions is that an antacid should:

• Alter gastrointestinal pH drastically for prolonged periods
• Have predictable, short-lived pH effect and limited systemic absorption
• Strongly chelate polyvalent drugs
• Induce hepatic enzymes

Correct Answer: Have predictable, short-lived pH effect and limited systemic absorption

Q10. Which antacid is likely to reduce absorption of tetracyclines and fluoroquinolones due to chelation?

• Sodium bicarbonate
• Aluminium-containing antacids
• Simethicone
• Sucralfate

Correct Answer: Aluminium-containing antacids

Q11. Buffering capacity of an antacid refers to:

• Ability to raise gastric pH above 8 permanently
• Resistance to pH change upon addition of acid
• Rate of absorption from GI tract
• Solid-state stability only

Correct Answer: Resistance to pH change upon addition of acid

Q12. Which parameter is used to compare neutralizing abilities quantitatively between antacids?

• Partition coefficient
• Acid neutralizing capacity (ANC)
• Half-life in plasma
• Melting point

Correct Answer: Acid neutralizing capacity (ANC)

Q13. For local action in stomach and minimal systemic effects, an antacid should be:

• Highly lipid-soluble and absorbable
• Poorly absorbed and act within the lumen
• Converted to active metabolites in liver
• Administered intravenously

Correct Answer: Poorly absorbed and act within the lumen

Q14. Which antacid can cause rebound acid hypersecretion if used chronically due to CO2 generation and stretch receptor effects?

• Aluminium hydroxide
• Magnesium hydroxide
• Sodium bicarbonate
• Calcium carbonate

Correct Answer: Sodium bicarbonate

Q15. Which property helps antacids to have prolonged action in the stomach?

• High solubility and rapid dissolution
• Low residence time in stomach
• Formation of poorly soluble salts and adherence to mucosa
• Complete systemic absorption

Correct Answer: Formation of poorly soluble salts and adherence to mucosa

Q16. Which antacid is contraindicated in renal failure due to risk of hypermagnesemia?

• Magnesium-containing antacids
• Aluminium-containing antacids
• Calcium carbonate
• Sodium bicarbonate

Correct Answer: Magnesium-containing antacids

Q17. An ideal antacid should not significantly affect the absorption of which of the following drugs?

• Tetracycline
• Iron salts
• Drugs with non-pH dependent absorption
• Fluoroquinolones

Correct Answer: Drugs with non-pH dependent absorption

Q18. Which antacid is often used as a chewable tablet due to high ANC per tablet and palatability?

• Aluminium hydroxide gel
• Magnesium hydroxide suspension
• Calcium carbonate
• Sodium bicarbonate solution

Correct Answer: Calcium carbonate

Q19. Which ideal property helps reduce interaction with concurrently administered oral drugs?

• High chelation capacity
• Non-reactivity and minimal adsorption to drugs
• Strong binding to anionic drugs
• Formation of insoluble complexes with antibiotics

Correct Answer: Non-reactivity and minimal adsorption to drugs

Q20. Which antacid component can lead to hypophosphatemia with prolonged use by binding phosphate in the gut?

• Magnesium salts
• Aluminium salts
• Sodium salts
• Potassium salts

Correct Answer: Aluminium salts

Q21. Which antacid property is critical in patients with hypertension or heart failure?

• High sodium content should be avoided
• High magnesium content is preferred
• High calcium is always safe
• Any antacid is permissible

Correct Answer: High sodium content should be avoided

Q22. A good antacid for rapid symptomatic relief of acid indigestion but not for long-term control is:

• Proton pump inhibitor
• Sodium bicarbonate
• Aluminium hydroxide gel
• H2 receptor antagonist

Correct Answer: Sodium bicarbonate

Q23. Which formulation factor improves antacid palatability for oral administration?

• Adding bitter salts
• Using suitable flavoring agents and sweeteners
• Removing any coating
• Increasing pH to alkaline range

Correct Answer: Using suitable flavoring agents and sweeteners

Q24. Which antacid property reduces risk of bacterial overgrowth or altered microbiota?

• Prolonged and excessive pH elevation
• Short-lived, controlled pH modification
• High systemic absorption
• Alkalinization of systemic blood

Correct Answer: Short-lived, controlled pH modification

Q25. Which antacid is known to interact with metoclopramide and decrease its absorption due to pH change?

• Aluminium hydroxide
• Sodium bicarbonate
• Magnesium hydroxide
• None; metoclopramide absorption is pH-independent

Correct Answer: None; metoclopramide absorption is pH-independent

Q26. Which property is crucial for antacid excipients when formulating a stable liquid antacid?

• High reactivity with active antacid
• Chemical compatibility and stability with active ingredients
• Promote rapid decomposition of active agent
• Enhance systemic absorption

Correct Answer: Chemical compatibility and stability with active ingredients

Q27. Why is aluminium hydroxide often combined with magnesium hydroxide in formulations?

• To increase diarrhea risk
• To balance constipating and laxative effects
• To increase systemic absorption
• To reduce palatability

Correct Answer: To balance constipating and laxative effects

Q28. Which antacid would you avoid in a patient with chronic hypercalcemia?

• Aluminium hydroxide
• Magnesium hydroxide
• Calcium carbonate
• Sucralfate

Correct Answer: Calcium carbonate

Q29. An ideal antacid should have what kind of onset and duration profile for acute relief?

• Slow onset and very long duration
• Rapid onset and moderate duration
• Delayed onset and short duration
• Rapid onset and permanent effect

Correct Answer: Rapid onset and moderate duration

Q30. Which antacid is most likely to increase urinary pH leading to altered excretion of some drugs?

• Sodium bicarbonate
• Aluminium hydroxide
• Simethicone
• Sucralfate

Correct Answer: Sodium bicarbonate

Q31. Which ideal property minimizes adverse gastrointestinal side effects like nausea or flatulence?

• Generating large volumes of gas on reaction
• Controlled neutralization without excessive CO2 production
• Strong systemic alkalinization
• High osmotic activity in intestine

Correct Answer: Controlled neutralization without excessive CO2 production

Q32. For drug compatibility studies, what is an important consideration for antacid-drug mixtures?

• Physical and chemical interactions including complexation or adsorption
• Only dissolution rate matters
• Systemic toxicity is irrelevant
• Flavor incompatibility only

Correct Answer: Physical and chemical interactions including complexation or adsorption

Q33. Which antacid is used as an emergency agent for acute hyperacidity but should not be used long-term due to systemic effects?

• Calcium carbonate
• Sodium bicarbonate
• Magnesium hydroxide
• Aluminium hydroxide

Correct Answer: Sodium bicarbonate

Q34. What role does viscosity or gel formation play in some antacid formulations?

• Speeds gastric emptying
• Enhances mucosal adherence and prolongs contact time
• Increases systemic absorption
• Promotes enzymatic degradation

Correct Answer: Enhances mucosal adherence and prolongs contact time

Q35. Which antigenic or allergic risk is associated with antacid use?

• Immunogenic protein content in simple mineral antacids is high
• Allergic reactions are rare but possible due to excipients or impurities
• All antacids cause IgE-mediated anaphylaxis
• Antacids suppress all immune responses

Correct Answer: Allergic reactions are rare but possible due to excipients or impurities

Q36. A critical formulation aim for chewable antacid tablets is:

• Increase gastric irritation
• Ensure pleasant taste, rapid disintegration and adequate ANC per chew
• Maximize systemic absorption
• Reduce ANC to zero

Correct Answer: Ensure pleasant taste, rapid disintegration and adequate ANC per chew

Q37. Which antacid is associated with aluminum accumulation and encephalopathy in patients with renal failure?

• Magnesium hydroxide
• Aluminium-containing antacids
• Calcium carbonate
• Sodium bicarbonate

Correct Answer: Aluminium-containing antacids

Q38. How do antacids affect the activity of pepsin in the stomach?

• Lowering pH enhances pepsin activity
• Increasing pH reduces pepsin activity and protein digestion
• Antacids directly activate pepsinogen
• Antacids stimulate intrinsic factor release

Correct Answer: Increasing pH reduces pepsin activity and protein digestion

Q39. Which antacid action can protect mucosa by forming a physical barrier over ulcers?

• Systemic alkalinization
• Sucralfate and alginate-based products forming protective layers
• Sodium bicarbonate absorption into mucosa
• Increasing bile secretion

Correct Answer: Sucralfate and alginate-based products forming protective layers

Q40. Which of the following is NOT an ideal property of an antacid?

• Predictable ANC and minimal systemic effects
• Interaction-free with common oral drugs
• High chelation with therapeutic antibiotics
• Palatable and chemically stable

Correct Answer: High chelation with therapeutic antibiotics

Q41. Which measurement unit is commonly used to express ANC in pharmacy practice?

• mEq HCl neutralized per gram or per dose
• mg/L per hour
• pKa units
• International units (IU)

Correct Answer: mEq HCl neutralized per gram or per dose

Q42. In formulating antacid suspensions, which property is important to ensure uniform dosing?

• Rapid sedimentation without redispersion
• Physical stability with easily redispersible suspension
• Phase separation with irreversible caking
• Crystallization of active ingredient

Correct Answer: Physical stability with easily redispersible suspension

Q43. Which antacid would be preferred in a patient at risk of kidney stones due to hypercalciuria?

• Calcium carbonate routinely
• Avoid excessive calcium-containing antacids; prefer magnesium or aluminium-based with caution
• Sodium bicarbonate recommended chronically
• High-dose calcium is protective

Correct Answer: Avoid excessive calcium-containing antacids; prefer magnesium or aluminium-based with caution

Q44. Which formulation strategy can prolong the residence time of an antacid in the stomach?

• Use of effervescent powders only
• Inclusion of bioadhesive or gel-forming agents
• Increase systemic absorption
• Minimize tablet size to pass quickly

Correct Answer: Inclusion of bioadhesive or gel-forming agents

Q45. Which antacid is most likely to interact with digoxin by altering GI pH and affecting its absorption?

• Aluminium hydroxide with minimal pH effect
• Sodium bicarbonate causing notable pH increase
• Simethicone only changes surface tension
• Sucralfate does not alter pH significantly

Correct Answer: Sodium bicarbonate causing notable pH increase

Q46. Which adverse effect is primarily linked to chronic aluminium antacid use?

• Hypermagnesemia
• Hypophosphatemia and osteomalacia
• Severe hypercalcemia
• Acute pancreatitis

Correct Answer: Hypophosphatemia and osteomalacia

Q47. What is the therapeutic rationale for combining antacids with alginate in some OTC products?

• Alginate increases systemic absorption of antacid
• Alginate forms a floating raft to prevent reflux and prolong contact
• Alginate neutralizes antacid effect
• Alginate converts antacid to a prodrug

Correct Answer: Alginate forms a floating raft to prevent reflux and prolong contact

Q48. Which antacid type is least likely to cause clinically significant electrolyte disturbances in patients with normal renal function when used occasionally?

• High-dose sodium bicarbonate chronically
• Occasional use of common over-the-counter antacids like magnesium or aluminium at recommended doses
• Continuous high-dose calcium carbonate
• Frequent use of magnesium hydroxide in renal failure

Correct Answer: Occasional use of common over-the-counter antacids like magnesium or aluminium at recommended doses

Q49. When assessing an antacid for compatibility with enteric-coated oral drugs, the main concern is:

• Systemic toxicity of the antacid
• Altering gastric pH and dissolving enteric coating prematurely
• Antacid color matching
• Palatability of enteric-coated tablet

Correct Answer: Altering gastric pH and dissolving enteric coating prematurely

Q50. An ideal antacid for hospital use should be all of the following EXCEPT:

• Predictable ANC and minimal drug interactions
• Cheap, stable and safe in renal impairment without monitoring
• Compatible with other medicines and easy to dose
• Provide rapid symptomatic relief when needed

Correct Answer: Cheap, stable and safe in renal impairment without monitoring

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com