Free DHA pharmacist exam mock test — 150 questions, 3 hours 🇦🇪

8 original practice questions written by Myndaq in the UAE Pharmacist License style. They are not taken from this mock paper or from official past papers. Try each one, then open the answer.

1. Question 1Clinical PharmacyOne correct answer

   A 61-year-old man with type 2 diabetes has taken metformin 1 g twice daily for several years. His latest renal function test shows an eGFR of 25 mL/min/1.73 m², down from 48 mL/min/1.73 m² a year ago. He has no other acute illness.

   What is the most appropriate recommendation regarding his metformin?

   1. A. Continue metformin 1 g twice daily and repeat renal function in 6 months
   2. B. Reduce metformin to 500 mg twice daily
   3. C. Stop metformin and discuss an alternative glucose-lowering agent with the prescriber
   4. D. Replace metformin with glibenclamide at the same frequency
   Show answer and explanation

   Answer: C

   Metformin is renally excreted and accumulates as kidney function falls, raising the risk of lactic acidosis. Current labelling contraindicates it when eGFR is below 30 mL/min/1.73 m², so it should be stopped and another agent chosen with the prescriber.

   Dose reduction (maximum about 1 g daily) is the approach when eGFR is between 30 and 45, not below 30, so B is wrong. Continuing the full dose (A) ignores the contraindication. Glibenclamide (D) is a long-acting sulfonylurea whose active metabolites are renally cleared, so it carries a high risk of prolonged hypoglycaemia in advanced kidney disease and should be avoided.

2. Question 2PharmacologyOne correct answer

   A 66-year-old man with a previous myocardial infarction takes simvastatin 40 mg at night, aspirin 75 mg daily and bisoprolol 5 mg daily. He is prescribed clarithromycin 500 mg twice daily for 7 days for a chest infection and asks the pharmacist whether he should keep taking all his tablets.

   Which is the most appropriate advice?

   1. A. Continue all medicines and have liver enzymes checked at the end of the course
   2. B. Reduce simvastatin to 20 mg at night during the course
   3. C. Withhold simvastatin until the clarithromycin course is finished, then restart it
   4. D. Take simvastatin in the morning so that it is 12 hours apart from clarithromycin
   Show answer and explanation

   Answer: C

   Clarithromycin is a strong CYP3A4 inhibitor, and simvastatin depends heavily on CYP3A4 for its first-pass metabolism. Together they can raise simvastatin exposure several-fold and cause myopathy or rhabdomyolysis, so the combination is contraindicated. For a short antibiotic course the usual advice is to pause simvastatin and restart it once the course is over (or use an antibiotic that does not interact, if clinically suitable).

   A lower simvastatin dose (B) is still a contraindicated combination. Separating doses (D) does not help because enzyme inhibition lasts throughout the course. Monitoring liver enzymes (A) does not address the main risk, which is muscle toxicity.

3. Question 3Pharmaceutical CalculationsType a numeric answer

   A 72-year-old woman weighing 60 kg has a serum creatinine of 1.2 mg/dL. Using the Cockcroft-Gault equation with her actual body weight, her estimated creatinine clearance in mL/min, to one decimal place, is ______.

   Show answer and explanation

   Answer: 40 to 40.2

   Cockcroft-Gault: CrCl = [(140 - age) × weight in kg] / (72 × serum creatinine in mg/dL), multiplied by 0.85 for a female patient.

   Numerator: (140 - 72) × 60 = 68 × 60 = 4080. Denominator: 72 × 1.2 = 86.4. 4080 / 86.4 = 47.22 mL/min. Female correction: 47.22 × 0.85 = 40.1 mL/min.

   A common error is forgetting the 0.85 factor, which gives 47.2 mL/min and could lead to an inappropriately high dose of a renally cleared drug.

4. Question 4PharmaceuticsOne correct answer

   According to the Noyes-Whitney equation, which change will INCREASE the dissolution rate of a poorly water-soluble drug from a tablet?

   1. A. Increasing the thickness of the diffusion layer around the particles
   2. B. Micronising the drug powder before compression
   3. C. Increasing the viscosity of the dissolution medium
   4. D. Using a more stable polymorph that has lower aqueous solubility
   Show answer and explanation

   Answer: B

   The Noyes-Whitney equation is dC/dt = D × A × (Cs - C) / (h × V), where D is the diffusion coefficient, A the surface area, Cs the saturation solubility and h the diffusion layer thickness. Micronising reduces particle size and greatly increases A, so the dissolution rate rises.

   A thicker diffusion layer (A) increases h and slows dissolution. A more viscous medium (C) lowers the diffusion coefficient D. A less soluble polymorph (D) lowers Cs and therefore the concentration gradient, so all three reduce the rate.

5. Question 5PharmacologyOne correct answer

   A 45-year-old woman with bipolar disorder has been stable on lithium carbonate for two years, with serum lithium levels consistently in the target range. She has started taking ibuprofen 400 mg three times daily for lower back pain.

   What is the most likely effect of this combination?

   1. A. Lithium levels fall because ibuprofen induces the hepatic metabolism of lithium
   2. B. Lithium levels rise because ibuprofen reduces the renal clearance of lithium
   3. C. There is no clinically important interaction between the two drugs
   4. D. Lithium levels rise because ibuprofen inhibits the CYP2C9 metabolism of lithium
   Show answer and explanation

   Answer: B

   Lithium is not metabolised; it is excreted unchanged by the kidneys. NSAIDs such as ibuprofen inhibit renal prostaglandin synthesis, reducing renal blood flow and lithium excretion, so serum lithium can climb into the toxic range (tremor, confusion, vomiting, ataxia).

   Options A and D are wrong because lithium undergoes no hepatic or CYP metabolism, so enzyme induction or inhibition cannot change its level. Option C is wrong because this is a well-recognised, clinically significant interaction. Paracetamol is the preferred analgesic; if an NSAID is essential, lithium levels and renal function should be monitored closely.

6. Question 6Drug InformationOne correct answer

   A physician asks for help interpreting a 3-year randomised controlled trial. Stroke occurred in 10% of patients in the control group and in 7.5% of patients in the group receiving the new treatment.

   How many patients need to be treated for 3 years to prevent one additional stroke?

   1. A. 4
   2. B. 10
   3. C. 13
   4. D. 40
   Show answer and explanation

   Answer: D

   The number needed to treat (NNT) is the reciprocal of the absolute risk reduction (ARR).

   ARR = 10% - 7.5% = 2.5% = 0.025. NNT = 1 / 0.025 = 40 patients treated for 3 years to prevent one stroke.

   The answer 4 comes from wrongly using the relative risk reduction (2.5/10 = 25%, and 1/0.25 = 4). The answers 10 and 13 come from taking the reciprocal of the raw event rates in each group instead of their difference.

7. Question 7Pharmaceutical CalculationsType a numeric answer

   A 70 kg patient is to receive dopamine at 5 micrograms/kg/min. The infusion is prepared by adding 400 mg of dopamine to 5% glucose to give a final volume of 250 mL. The infusion pump rate required, in mL/h to one decimal place, is ______.

   Show answer and explanation

   Answer: 13.1

   Concentration: 400 mg / 250 mL = 1.6 mg/mL = 1600 micrograms/mL.

   Dose: 5 micrograms/kg/min × 70 kg = 350 micrograms/min. Per hour: 350 × 60 = 21,000 micrograms/h.

   Rate: 21,000 / 1600 = 13.125 mL/h, which is 13.1 mL/h to one decimal place.

   Forgetting to convert minutes to hours gives 0.22 mL/h, and forgetting the patient's weight gives about 0.19 mL/h; both would badly underdose the patient.

8. Question 8Clinical PharmacyOne correct answer

   A 67-year-old woman with postmenopausal osteoporosis has been started on alendronic acid 70 mg once weekly. She usually takes her other morning medicines with breakfast and a glass of milk.

   Which counselling advice is most appropriate for her alendronic acid tablet?

   1. A. Take it with breakfast and a full glass of water to reduce stomach upset
   2. B. Take it at bedtime with water so that it is well away from her other medicines
   3. C. Take it with plain water on rising, stay upright, and delay breakfast and other medicines for 30 minutes
   4. D. Take it with a glass of milk or calcium-fortified orange juice to help protect the bones
   Show answer and explanation

   Answer: C

   Oral bisphosphonates are very poorly absorbed, and absorption is reduced further by food, calcium and other drinks. They can also cause oesophageal irritation and ulceration if the tablet lodges in the oesophagus. So the tablet should be taken on an empty stomach with plain water, with the patient staying upright for at least 30 minutes and delaying food, drinks and other medicines for at least 30 minutes.

   Taking it with breakfast (A) or with milk or calcium-fortified juice (D) blocks absorption because calcium chelates the drug. Taking it at bedtime (B) means lying down soon after the dose, which increases the risk of oesophagitis.