Original DHA nursing questions on pharmacology & medication safety, with explanations.
Short answer: 10 original multiple-choice practice questions on pharmacology & medication safety for nurses preparing for the DHA licensing exam, each with the correct answer and a full explanation. This is a Meddex topic, not a DHA heading. They are original and are not real exam items.
About these questions
Every question here is original. Meddex wrote it for exam preparation. None is a real, recalled or leaked exam item, and none comes from DHA, Prometric, UAE University or the NIHS.
Meddex is independent and is not affiliated with DHA, Prometric, UAE University or the NIHS.
Clinical review of the question bank is not complete yet. Treat the explanations as study aids and check official guidance before you rely on a fact.
This is a sample, not the whole bank, and doing well on it does not predict an exam result.
What pharmacology covers
Drug classes, interactions, adverse effects and dose calculations.
Check the patient, the drug, the dose, the route and the time before you give anything, and take extra care with high-alert medicines and look-alike names. When the stem gives numbers, do the arithmetic before you read the options.
Where it fits in the exam
DHA lists four coverage headings for Registered Nurse and publishes no weights. Pharmacology & Medication Safety is one of ten Meddex domains, so it is a Meddex grouping and not a DHA heading. Its questions can appear under more than one DHA heading.
DHA does not state how many answer options its questions have or whether each has one best answer. Meddex practice items use four options with one best answer, as a practice format.
How to use these questions
Decide your answer before you press Show answer. Then read the reason for every option, including the ones you rejected. Note the idea you missed and come back to it in a few days.
Practice questions
Question 1
Pharmacology & Medication SafetyMedium
A nurse is preparing a prescribed dose of 8 units of soluble (clear) insulin and 20 units of isophane (cloudy) insulin in one syringe. Which sequence is correct?
AOption A: Mix the two insulins in an empty sterile vial, then draw up the total of 28 units from that vial in one step
BOption B: Draw up the clear insulin first, then the cloudy, so the clear vial stays uncontaminated
COption C: Draw up the cloudy insulin first, then the clear insulin, so that the longer-acting dose is measured most accurately
DOption D: Draw up each insulin in its own syringe and inject them one after the other into the same injection site
Show answer for question 1
Correct answer: B. Draw up the clear insulin first, then the cloudy, so the clear vial stays uncontaminated
The clear (soluble) insulin is drawn up first and the cloudy (isophane) insulin second. If the cloudy insulin went into the syringe first, a little would be carried into the clear vial and alter its action. The cloudy vial is gently rolled first, air is injected into both vials, and the total of 28 units is drawn up into one syringe.
Why A is wrong. Mixing insulins in an empty vial is not an accepted practice and gives an unreliable dose.
Why C is wrong. Drawing the cloudy insulin first risks carrying it into the clear vial, which changes the action of the stock.
Why D is wrong. Two injections into the same site are not needed when the prescriber has ordered a mixed dose in one syringe.
Topic: Insulin - drawing up two insulins in one syringe. Reference: BNF: Insulin; Mayo Clinic: Insulin (parenteral route), proper use
Question 2
Pharmacology & Medication SafetyMedium
A child weighing 14 kg is prescribed amoxicillin 30 mg/kg/day in three equal doses. The oral suspension contains 250 mg in 5 mL. What volume should the nurse give for each dose?
AOption A: 5.6 mL
BOption B: 1.4 mL
COption C: 8.4 mL
DOption D: 2.8 mL
Show answer for question 2
Correct answer: D. 2.8 mL
Daily dose = 14 kg x 30 mg/kg = 420 mg. Each dose = 420 mg / 3 = 140 mg. Volume = 140 mg x 5 mL / 250 mg = 2.8 mL. A volume of 8.4 mL is the whole day's dose, 1.4 mL halves the volume, and 5.6 mL doubles it.
Why A is wrong. 5.6 mL is 280 mg, which is double the intended dose.
Why B is wrong. 1.4 mL is 70 mg, half of the dose, as if the strength were 500 mg in 5 mL.
Why C is wrong. 8.4 mL is 420 mg, the whole daily dose given at once.
Topic: Paediatric dosing - amoxicillin suspension volume. Reference: BNF for Children: Amoxicillin; Gatford and Phillips Nursing Calculations
Question 3
Pharmacology & Medication SafetyMedium
A nurse is to give an adult an intravenous phenytoin loading dose of 1,000 mg for recurrent seizures. Which approach is correct?
AOption A: Give it by deep intramuscular injection, which gives a steady and reliable level
BOption B: Give it as a rapid push over two minutes so that a therapeutic level is reached quickly
COption C: Infuse at no more than 50 mg/min with ECG and blood pressure monitoring
DOption D: Dilute it in 5 percent glucose to reduce irritation of the vein during the infusion
Show answer for question 3
Correct answer: C. Infuse at no more than 50 mg/min with ECG and blood pressure monitoring
Intravenous phenytoin is given at no more than 50 mg/min in adults, with continuous ECG and blood pressure monitoring, because fast infusion can cause hypotension and arrhythmia. A 1,000 mg dose therefore takes at least 20 minutes. It is given into a large vein and flushed with sodium chloride 0.9 percent, as it can precipitate in glucose.
Why A is wrong. Intramuscular phenytoin is absorbed slowly and erratically and is not used for a loading dose.
Why B is wrong. A rapid push of 1,000 mg over two minutes would be about 500 mg/min and risks severe hypotension and arrhythmia.
Why D is wrong. Phenytoin can precipitate in glucose solutions, so it is not diluted in glucose.
A nurse is about to give a prophylactic dose of enoxaparin from a pre-filled syringe to an adult. Which technique is correct?
AOption A: Inject into a held fold of abdominal skin and do not rub the site afterwards
BOption B: Expel the small air bubble from the syringe so that no air enters the tissue
COption C: Inject into the abdomen, then rub the site firmly to help the drug spread
DOption D: Pull back on the plunger after insertion to check that no blood returns
Show answer for question 4
Correct answer: A. Inject into a held fold of abdominal skin and do not rub the site afterwards
The air bubble in a pre-filled enoxaparin syringe is left in place, because expelling it can lose some of the dose. The needle goes in at 90 degrees into a fold of abdominal skin, away from the umbilicus, and the fold is held until the needle has been withdrawn. The site is not rubbed, because rubbing increases bruising, and aspiration is not used. Sites are alternated between the two sides of the abdomen.
Why B is wrong. Expelling the air bubble can waste some of the dose, so it is left in the syringe.
Why C is wrong. Rubbing the site increases bruising under the skin.
Why D is wrong. Aspiration is not recommended for this injection and is not part of the technique.
Topic: Enoxaparin - subcutaneous injection technique. Reference: BNF: Enoxaparin sodium; Clexane (enoxaparin) Dosage and Administration Guide, Sanofi UK
Question 5
Pharmacology & Medication SafetyMedium
A 12 kg child is prescribed ceftriaxone 50 mg/kg by intravenous injection. The reconstituted solution contains 100 mg/mL. What volume should be drawn up?
AOption A: 3 mL
BOption B: 6 mL
COption C: 60 mL
DOption D: 12 mL
Show answer for question 5
Correct answer: B. 6 mL
The dose is 50 x 12 = 600 mg. At 100 mg/mL the volume is 600 / 100 = 6 mL. Checking that the result is reasonable and having a second nurse verify high-risk paediatric calculations reduces error.
Why A is wrong. 3 mL would deliver 300 mg, half the dose.
Why C is wrong. 60 mL would be ten times the dose.
Why D is wrong. 12 mL would deliver 1200 mg, double the dose.
Topic: Paediatric ceftriaxone volume. Reference: British National Formulary for Children (ceftriaxone); Royal Marsden Manual of Clinical Nursing Procedures
Question 6
Pharmacology & Medication SafetyMedium
Before giving a scheduled dose of digoxin, the nurse measures an apical pulse of 52 beats per minute over a full minute. What should the nurse do?
AOption A: Give the dose with extra oral fluids to offset the effect on heart rate
BOption B: Hold the dose, check for signs of toxicity, and notify the prescriber
COption C: Give the dose as prescribed and recheck the pulse after one hour
DOption D: Give half the dose and ask the prescriber to review it at the next ward round
Show answer for question 6
Correct answer: B. Hold the dose, check for signs of toxicity, and notify the prescriber
A heart rate below the parameter set in the order (commonly 60) can indicate toxicity. Hold the dose, check for other signs such as nausea or visual changes, and inform the prescriber.
Why A is wrong. Extra fluids do not change the effect of digoxin on the heart rate.
Why C is wrong. Giving the dose despite a pulse below 60 risks worsening bradycardia and heart block if toxicity is present.
Why D is wrong. Nurses do not alter prescribed doses without an order, and halving does not remove the risk.
A man has taken clozapine 300 mg daily for two years. He was too unwell with vomiting to take any doses for the three days before admission, and the chart says 300 mg tonight. What should the nurse do?
AOption A: Give a double dose tonight to make up for the three missed days and restore his blood levels
BOption B: Hold the dose and ask the prescriber to restart from a low dose, because tolerance is lost after more than 48 hours
COption C: Give the usual 300 mg, as he has been stable on it for two years
DOption D: Give 150 mg tonight and then continue at 300 mg from tomorrow once he tolerates it
Show answer for question 7
Correct answer: B. Hold the dose and ask the prescriber to restart from a low dose, because tolerance is lost after more than 48 hours
After a gap of more than 48 hours in clozapine, tolerance to its effects is lost, and restarting at the usual dose can cause profound hypotension, bradycardia, syncope or collapse. The prescriber is asked to restart at a low dose, such as 12.5 mg, and increase gradually with monitoring of blood pressure and pulse, and the blood monitoring schedule is checked with the pharmacy.
Why A is wrong. A double dose adds to the risk of collapse.
Why C is wrong. Giving the old dose after a three day gap risks collapse.
Why D is wrong. Even 150 mg is far above a safe restart dose after a long gap.
Topic: Restarting clozapine after missed doses. Reference: British National Formulary (clozapine); Maudsley Prescribing Guidelines in Psychiatry
Question 8
Pharmacology & Medication SafetyMedium
A child weighing 18 kg is prescribed paracetamol 15 mg/kg orally. The suspension contains 120 mg in 5 mL. What volume should the nurse draw up?
AOption A: 9.0 mL
BOption B: 5.63 mL
COption C: 11.25 mL
DOption D: 22.50 mL
Show answer for question 8
Correct answer: C. 11.25 mL
Dose = 15 mg/kg x 18 kg = 270 mg. Concentration is 120 mg per 5 mL, which is 24 mg/mL, so volume = 270 / 24 = 11.25 mL. Taking 270 divided by 12 gives 22.5 mL, a common error from misreading the concentration.
Why A is wrong. This corresponds to 216 mg (12 mg/kg), not the prescribed 15 mg/kg.
Why B is wrong. This corresponds to roughly half the correct dose (about 135 mg) and would under-treat.
Why D is wrong. This divides by 12 mg/mL, which is an error from reading 120 mg/5 mL, and would double the dose.
Topic: Paediatric dosing - paracetamol. Reference: BNF for Children: Paracetamol; Boyer Math for Nurses
Question 9
Pharmacology & Medication SafetyMedium
A nurse must give ceftriaxone in 100 mL of 0.9% sodium chloride over 30 minutes by gravity infusion. The giving set delivers 20 drops per mL. At what rate should the drip be set?
AOption A: 50 drops/min
BOption B: 67 drops/min
COption C: 33 drops/min
DOption D: 100 drops/min
Show answer for question 9
Correct answer: B. 67 drops/min
Drip rate = volume (mL) x drop factor (drops/mL) / time (min) = 100 x 20 / 30 = 66.7, which rounds to 67 drops per minute. Using 10 or 15 drops/mL gives 33 or 50, and 100 ignores the time and drop factor.
Why A is wrong. This uses a 15 drops/mL set (100 x 15 / 30) rather than 20 drops/mL.
Why C is wrong. This uses a 10 drops/mL set (100 x 10 / 30) rather than 20 drops/mL.
Why D is wrong. This simply repeats the volume and ignores the drop factor and the 30-minute time.
Topic: IV drip rate calculation. Reference: Boyer Math for Nurses; BNF: Ceftriaxone
Question 10
Pharmacology & Medication SafetyMedium
A postoperative patient with a morphine PCA is hard to rouse. His respiratory rate is 8/min and SpO2 is 91% on room air. What should the nurse do first?
AOption A: Reposition him and recheck the respiratory rate in 30 minutes
BOption B: Stop the PCA, stimulate him, give oxygen and call for urgent help
COption C: Reduce the PCA bolus and reassess after an hour of sleep
DOption D: Give a full 400 microgram naloxone dose IV before any other action
Show answer for question 10
Correct answer: B. Stop the PCA, stimulate him, give oxygen and call for urgent help
Reduced consciousness with a respiratory rate of 8/min indicates opioid toxicity. The infusion is stopped, he is stimulated, oxygen and airway support are provided and help is called; naloxone is titrated in small doses by a prescriber or protocol if needed. A full bolus can reverse analgesia abruptly and cause withdrawal.
Why A is wrong. Waiting 30 minutes delays treatment for a patient who is already hypoventilating.
Why C is wrong. Continuing the PCA at a lower bolus leaves him on a drug that is already depressing breathing.
Why D is wrong. A full bolus is not the first step and can cause severe pain, withdrawal and pulmonary oedema; it is titrated.
Meddex is an independent preparation platform and is not affiliated with, endorsed by, or sponsored by the Dubai Health Authority (DHA), Prometric, UAE University or the National Institute of Health Specialties (NIHS). Always confirm exam details on the official websites. Last reviewed .
Frequently asked questions
DHA does not publish how many questions come from each topic. It lists four coverage headings for Registered Nurse with no weights. Meddex groups its questions into ten domains of its own.
No. They are original practice questions written by Meddex for exam preparation. DHA does not publish sample questions, and its Assessment Manual says sharing assessment questions is not allowed, so we do not use or claim real or recalled items.
The Meddex app has the full bank, which you can practise by topic with a free account. These pages are a short sample, and the questions on them do not change.
No. Each question has a Show answer button. The answer, the explanation and the reason each wrong option is wrong are part of the page text, so they are there when you press it.