Pharmaceutical incompatibilities are undesirable reactions that can occur when mixing drug substances and excipients, potentially affecting the safety, efficacy, and appearance of a formulation. For B.Pharm students, mastering the ability to identify, prevent, and correct physical, chemical, and therapeutic incompatibilities is a fundamental aspect of compounding and dispensing. This quiz will test your knowledge of this critical subject, which is essential for ensuring patient safety.
- A pharmaceutical incompatibility is an unintended reaction between two or more components of a prescription that results in an undesirable:
- Therapeutic effect
- Product
- Cost
- Flavor
- Which of the following is a primary classification of pharmaceutical incompatibilities?
- Physical
- Chemical
- Therapeutic
- All of the above
- The formation of a liquid when two solid substances are mixed together is an example of:
- Precipitation
- Immiscibility
- A eutectic mixture
- Hydrolysis
- When the action of one drug is opposed by another drug, it is known as:
- Synergism
- Potentiation
- Antagonism
- Addition
- The mixing of oil and water, which results in two separate layers, is a classic example of:
- Insolubility
- Immiscibility
- Precipitation
- Liquefaction
- An incompatibility that involves a chemical reaction, resulting in the formation of new chemical compounds, is a:
- Physical incompatibility
- Chemical incompatibility
- Therapeutic incompatibility
- Intentional incompatibility
- Prescribing a drug to which a patient is allergic is an example of:
- Physical incompatibility
- Chemical incompatibility
- Therapeutic incompatibility
- A eutectic mixture
- The precipitation of an alkaloidal salt from an aqueous solution upon the addition of an alkaline substance is a common example of:
- A physical incompatibility
- A chemical incompatibility
- A therapeutic incompatibility
- An intended reaction
- How can the liquefaction of a eutectic mixture be prevented?
- By heating the mixture
- By mixing the components with an inert adsorbent powder separately
- By adding more water
- By storing it in a humid place
- A change in the physical state, such as solubility or appearance, without a change in chemical structure is a ______ incompatibility.
- physical
- chemical
- therapeutic
- pharmacological
- The evolution of carbon dioxide gas when carbonates or bicarbonates are mixed with an acidic substance is a:
- Physical incompatibility
- Chemical incompatibility
- Therapeutic incompatibility
- Desirable reaction
- What is the first step a pharmacist should take upon detecting a therapeutic incompatibility?
- Dispense the prescription as written
- Modify the prescription without consultation
- Contact the prescriber for clarification or correction
- Inform the patient that the prescription is invalid
- “Salting out,” the precipitation of a substance from a solution by the addition of an electrolyte, is a type of:
- Chemical incompatibility
- Therapeutic incompatibility
- Physical incompatibility
- Redox reaction
- Oxidation-reduction (redox) reactions are a common cause of:
- Physical incompatibility
- Chemical incompatibility
- Therapeutic incompatibility
- Immiscibility
- A prescription for a tetracycline antibiotic with an antacid containing calcium is an example of a potential:
- Physical incompatibility (eutectic)
- Chemical incompatibility (color change)
- Therapeutic incompatibility (decreased absorption)
- Physical incompatibility (immiscibility)
- Insolubility of a prescribed drug in the vehicle is an example of:
- Physical incompatibility
- Chemical incompatibility
- Therapeutic incompatibility
- A contraindicated drug
- A color change in a formulation due to a chemical reaction indicates a(n) ______ incompatibility.
- physical
- chemical
- therapeutic
- acceptable
- An error in the dosage regimen, such as prescribing an overdose, is considered a:
- Physical incompatibility
- Chemical incompatibility
- Therapeutic incompatibility
- Formulation error
- How can the precipitation of a resinous tincture when added to water be prevented?
- By adding the tincture very slowly to the water with vigorous stirring
- By heating the water
- By adding an acid
- By adding salt
- Hydrolysis is a chemical reaction involving the breakdown of a substance by:
- Air
- Light
- Water
- An enzyme
- Which of the following would NOT be considered a pharmaceutical incompatibility?
- A change in the color of a solution over time
- The formation of a precipitate when two solutions are mixed
- A patient experiencing an expected side effect at a normal dose
- The liquefaction of a powder mixture
- The use of amber-colored bottles is a common method to prevent which type of chemical incompatibility?
- Hydrolysis
- Oxidation
- Photochemical degradation
- Acid-base reaction
- The combination of two drugs leading to a greater effect than the sum of their individual effects is known as:
- Antagonism
- Synergism
- Tolerance
- Idiosyncrasy
- Which of the following is a physical incompatibility?
- A drug overdose
- A drug-drug interaction
- Insolubility
- A redox reaction
- The formation of an insoluble precipitate when solutions of lead acetate and zinc sulfate are mixed is due to a:
- Physical change
- Double decomposition reaction
- Eutectic mixture
- Redox reaction
- What is the most common reason for therapeutic incompatibility?
- The pharmacist’s error
- An error in the prescription by the prescriber
- The patient not following instructions
- The drug being expired
- Altering the order of mixing is a common way to correct some ______ incompatibilities.
- physical
- chemical
- therapeutic
- all
- The use of antioxidants like ascorbic acid can prevent:
- Hydrolysis
- Oxidation
- Precipitation
- Eutectic formation
- Which of the following is a classic example of a eutectic mixture?
- Camphor and menthol
- Sodium chloride and water
- Oil and water
- Aspirin and antacid
- A prescription containing contraindicated drugs is a type of ______ incompatibility.
- physical
- chemical
- therapeutic
- procedural
- Adding a suspending agent can be a correction for which incompatibility?
- Immiscibility of two liquids
- Insolubility of a solid in a liquid
- A chemical reaction
- A drug overdose
- A change in the consistency of an ointment or cream upon mixing ingredients is a ______ incompatibility.
- physical
- chemical
- therapeutic
- dosage
- A chemical incompatibility that has been adjusted for by the pharmacist (e.g., by changing a component after consulting the prescriber) is sometimes called a(n):
- Absolute incompatibility
- Tolerated incompatibility
- Adjusted incompatibility
- Unavoidable incompatibility
- Prescribing the wrong drug for a particular disease is a form of ______ incompatibility.
- physical
- chemical
- therapeutic
- formulation
- The reaction between an oxidizing agent (like KMnO₄) and a reducing agent (like glycerin) is a ______ incompatibility.
- physical
- chemical
- therapeutic
- intentional
- Which of the following is a physical incompatibility?
- Adsorption of a drug onto the container
- A drug-drug interaction
- An incorrect dose
- An allergic reaction
- The use of a chelating agent like EDTA can prevent chemical incompatibilities caused by:
- Light
- Air
- Trace metal ions
- Water
- The separation of an emulsion into two distinct layers is a type of ______ incompatibility.
- physical
- chemical
- therapeutic
- intentional
- Which of these is NOT a method for correcting a chemical incompatibility?
- Changing the solvent
- Using a different salt form of the drug
- Adding a buffering agent
- Adding a suspending agent
- A pharmacist is responsible for detecting and resolving which types of incompatibilities?
- Physical and Chemical
- Therapeutic
- Both A and B
- None of the above
- The interaction between two prescribed drugs is a type of:
- Physical incompatibility
- Chemical incompatibility
- Therapeutic incompatibility
- Formulation incompatibility
- Adding an emulsifying agent is a method to correct the incompatibility of:
- Two immiscible liquids
- Two eutectic solids
- An insoluble solid in a liquid
- An acid and a base
- A precipitate forms due to a pH change. This is best described as a(n):
- Physicochemical incompatibility
- Therapeutic incompatibility
- Absolute incompatibility
- Drug-drug interaction
- Which is a common outcome of a chemical incompatibility?
- Improved therapeutic effect
- Loss of drug potency
- Increased solubility
- A more elegant preparation
- The presence of both synergism and antagonism falls under which category of incompatibility?
- Physical
- Chemical
- Therapeutic
- Formulation
- How is the incompatibility of an insoluble powder in a liquid vehicle typically handled?
- By adding an emulsifier
- By adding a suspending agent to form a suspension
- By changing the drug
- By heating the liquid
- The term “tolerated” incompatibility refers to a reaction where:
- The prescription is dispensed as is, despite the reaction.
- The chemical reaction is minimized by altering the mixing order, but not completely eliminated.
- The prescriber is contacted to change the drug.
- The patient tolerates the side effects.
- Which of the following best describes a physical incompatibility?
- It is always visible to the naked eye.
- It involves the formation of a new molecule.
- It is a change that is undesirable but does not involve a chemical reaction.
- It only occurs in liquid dosage forms.
- A prescription for a solution of strychnine hydrochloride (an alkaloidal salt) and aromatic spirit of ammonia (alkaline) would result in:
- A eutectic mixture
- Precipitation of the free strychnine base
- A synergistic therapeutic effect
- A clear, stable solution
- The ultimate responsibility for identifying and resolving incompatibilities before dispensing rests with the:
- Patient
- Prescriber
- Pharmacist
- Nurse
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.
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