DHA Pharmacist 5 — Questions and Answers
Question 1: A patient with a creatinine clearance of 25 mL/min is prescribed a renally cleared antibiotic. What dose adjustment strategy is most appropriate?
- Increase the dose and shorten the dosing interval
- Reduce the dose, extend the dosing interval, or both (Correct answer)
- No adjustment needed since absorption is unaffected
- Switch to a hepatically metabolized drug with no change
Correct answer: Reduce the dose, extend the dosing interval, or both
For renally cleared drugs, dose reduction and/or interval extension is necessary in renal impairment to prevent drug accumulation and toxicity.
Question 2: Which controlled substance schedule under UAE law includes drugs with accepted medical use but high potential for abuse, such as morphine?
- Schedule I
- Schedule II
- Table I (First Schedule) (Correct answer)
- Category B
Correct answer: Table I (First Schedule)
Under UAE Federal Law No. 14 of 1995, morphine and similar opioids are classified under the First Schedule (Table I), which governs narcotics with strict prescribing requirements.
Question 3: A pharmacist receives a prescription for sildenafil for a patient who is also taking isosorbide mononitrate. What should the pharmacist do?
- Dispense both medications with food recommendations
- Counsel the patient to take them 4 hours apart
- Refuse to dispense sildenafil and contact the prescriber immediately (Correct answer)
- Dispense at half the sildenafil dose
Correct answer: Refuse to dispense sildenafil and contact the prescriber immediately
The combination of PDE5 inhibitors with nitrates is absolutely contraindicated due to severe hypotension risk; the pharmacist must withhold dispensing and contact the prescriber.
Question 4: What is the primary advantage of using the AUC (area under the concentration-time curve) to measure drug exposure?
- It identifies the time to peak drug concentration
- It provides a measure of total systemic drug exposure over time (Correct answer)
- It predicts the rate of drug absorption only
- It quantifies protein binding affinity
Correct answer: It provides a measure of total systemic drug exposure over time
AUC represents the total drug exposure over time and is used to compare bioavailability, calculate clearance, and guide dosing decisions.
Question 5: A patient taking lithium for bipolar disorder is started on hydrochlorothiazide. What monitoring is most critical?
- Blood glucose levels
- Serum lithium levels for toxicity (Correct answer)
- Liver function tests
- Thyroid-stimulating hormone (TSH)
Correct answer: Serum lithium levels for toxicity
Thiazide diuretics reduce renal sodium and lithium excretion, increasing lithium serum levels and the risk of lithium toxicity.
Question 6: Under DHA guidelines, which of the following must be documented in a pharmacy's dispensing record for a controlled substance?
- Patient's insurance provider only
- Prescriber's name, drug name, quantity dispensed, patient identity, and prescription date (Correct answer)
- Only the drug name and expiry date
- The patient's chief complaint and diagnosis
Correct answer: Prescriber's name, drug name, quantity dispensed, patient identity, and prescription date
DHA and UAE regulations require comprehensive documentation for controlled substance dispensing, including prescriber details, patient identification, drug particulars, and date to ensure traceability.
Question 7: Which of the following best describes 'therapeutic substitution' in pharmacy practice?
- Dispensing a generic version of the same drug molecule
- Replacing a prescribed drug with a pharmacologically similar drug from a different chemical class (Correct answer)
- Splitting a tablet to achieve a lower dose
- Compounding a drug not available commercially
Correct answer: Replacing a prescribed drug with a pharmacologically similar drug from a different chemical class
Therapeutic substitution involves replacing a prescribed drug with a therapeutically equivalent agent from a different chemical class, which requires prescriber authorization.
DHA Pharmacist 5
A patient with a creatinine clearance of 25 mL/min is prescribed a renally cleared antibiotic.
What dose adjustment strategy is most appropriate?