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💊 GCC Nursing Exam Essential

Drug Calculations for
GCC Nurses

Pass your licensing exam and never make a medication error. Master every formula, practice 50 real exam-style problems, and use our interactive calculators.

DHA Exam SCHS Exam QCHP Exam 6 Interactive Calculators 50 Practice Problems
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Units of Measurement — Quick Reference

Weight

kg› g› mg› mcg (μg)› ng
1 kg = 1,000 g 1 g = 1,000 mg 1 mg = 1,000 mcg 1 mcg = 1,000 ng

Volume

L› mL
1 L = 1,000 mL 1 mL = 1 cc

Concentration

mg/mL (most common) g/100mL = % mcg/mL (ICU drips) mmol/L (electrolytes) units/mL (insulin, heparin)

Common % Conversions

1% = 10 mg/mL 0.9% NaCl = 9 mg/mL 5% Dextrose = 50 mg/mL 50% Dextrose = 500 mg/mL 20% Mannitol = 200 mg/mL
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Drug Calculation Formulas — Reference Card

Basic Tablet / Capsule
Dose Required ÷ Dose Available × Quantity = Tablets to give
Also written as: "Want ÷ Got × Quantity" — the universal formula
Liquid Oral / Injectable
(Dose Required ÷ Dose Available) × Volume = Volume to give (mL)
Example: Need 500mg, have 250mg/5mL → (500÷250)×5 = 10 mL
IV Infusion Rate
Volume (mL) ÷ Time (hours) = Rate (mL/hr)
For pump setting — most common calculation on GCC exams
Drip Rate — Gravity (drops/min)
Volume (mL) ÷ Time (min) × Drop Factor = Drops/min
Drop factors: 20 gtt/mL (standard), 60 gtt/mL (microdrip/paediatric)
Weight-Based Dose
Weight (kg) × Dose (mg/kg) = Total Dose (mg)
Always round weight to nearest 0.1 kg; use actual body weight unless otherwise stated
Concentration
Amount (mg) ÷ Volume (mL) = Concentration (mg/mL)
Convert to mcg/mL by multiplying by 1000 when needed for vasoactive drugs
IV Rate from Weight-Based Dose (mcg/kg/min)
Dose (mcg/kg/min) × Weight (kg) ÷ Conc (mcg/mL) × 60 = mL/hr
The ×60 converts minutes to hours. Used for dopamine, noradrenaline, dobutamine etc.
Percentage Solutions
X% = X g per 100 mL = X × 10 mg/mL
5% dextrose = 5g/100mL = 50mg/mL = 50g per litre
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Interactive Drug Calculators

Basic Dose Calculator — Tablets, Capsules & Liquids

Amount to Give

IV Rate Calculator — mL/hr & Drops/min

IV Pump Rate
mL/hr
Drip Rate (gravity)
drops/min

Weight-Based Dose Calculator

Total Dose

Infusion Rate from Dose Calculator — ICU Drips

Presets:
Pump Rate
mL/hr

Drip Rate Calculator — Gravity Administration

Drip Rate
drops/min

Percentage Solution Calculator

Concentration
mg/mL
g/100mL
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50 Practice Problems — Exam Style Quiz

Score: 0 / 50  |  Answered: 0
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Common Drug Concentrations in GCC Hospitals

Drug Standard GCC Dilution Concentration Common Dose Range Nursing Notes
Dopamine HIGH ALERT 200mg/50mL NS
400mg/250mL NS		 4 mg/mL
1.6 mg/mL		 2–20 mcg/kg/min Renal dose <5; cardiac 5-10; vasopressor >10 mcg/kg/min. Central line preferred at high doses.
Dobutamine HIGH ALERT 250mg/250mL NS or D5W 1 mg/mL = 1000 mcg/mL 2.5–20 mcg/kg/min Inotrope — increases CO. Monitor HR (tachycardia common). Central line preferred.
Noradrenaline HIGH ALERT 4mg/50mL NS
8mg/250mL NS		 80 mcg/mL
32 mcg/mL		 0.01–0.5 mcg/kg/min CENTRAL LINE ONLY. Potent vasoconstrictor. Monitor for extravasation. Titrate to MAP >65.
Adrenaline (Epinephrine) HIGH ALERT 4mg/50mL NS 80 mcg/mL 0.01–0.5 mcg/kg/min Central line. Cardiac arrest: 1mg IV bolus (1:10,000). Anaphylaxis: 0.5mg IM (1:1000).
Heparin Infusion HIGH ALERT 25,000 units/50mL NS 500 units/mL Weight-based protocol Requires 2-nurse check. Monitor APTT. Antidote: Protamine sulphate. No IM injections.
Insulin Actrapid HIGH ALERT 50 units/50mL NS 1 unit/mL Variable per protocol Requires 2-nurse check. Monitor BGL hourly. DKA: 0.1 units/kg/hr. Hypoglycaemia antidote: 50% dextrose.
Propofol 200mg/20mL vial
1000mg/100mL		 10 mg/mL 0.3–4 mg/kg/hr (ICU sedation) White emulsion — discard after 12 hrs. Watch for propofol infusion syndrome at high doses/prolonged use.
Fentanyl HIGH ALERT 500mcg/50mL NS 10 mcg/mL 1–4 mcg/kg/hr Opioid — respiratory depression. Antidote: Naloxone. 100× more potent than morphine.
Midazolam 50mg/50mL NS 1 mg/mL 0.02–0.1 mg/kg/hr Benzodiazepine. Antidote: Flumazenil. Monitor level of sedation (RASS score).
GTN (Nitroglycerin) 50mg/50mL D5W 1 mg/mL 0.5–10 mg/hr Use non-PVC giving set (GTN absorbs into PVC). Monitor BP. Hypotension common.
Amiodarone 300mg/50mL D5W (loading)
900mg/500mL D5W (maint)		 6 mg/mL
1.8 mg/mL		 Loading: 300mg over 1hr; Maint: 900mg over 23hr Phlebitis risk — CVC preferred. Incompatible with NS. Monitor ECG.
Magnesium Sulphate HIGH ALERT 10g/100mL NS (10%)
2g/50mL (loading)		 100 mg/mL Eclampsia: 4g load, 1g/hr maint Check reflexes, RR, UO hourly. Antidote: Calcium gluconate 10% IV.
Morphine HIGH ALERT 10mg/mL ampoule
PCA: 1mg/mL		 1–10 mg/mL Acute: 0.1mg/kg IV titrated Opioid — respiratory depression. Antidote: Naloxone. Caution in renal failure.
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Exam Tips for Drug Calculations — DHA, SCHS, QCHP

  • ✏️
    Show all working: Even if your final answer is wrong, most GCC licensing exams award marks for correct method. Write every step clearly.
  • 🏷️
    Always write units: Never write a bare number. Every value must have its unit — mg, mL, drops/min, mL/hr. Examiners can deduct marks for missing units.
  • 🤔
    Sanity check your answer: Could you really give 50 tablets? Is 0.003 mL measurable? A dose of 400 mL for one injection is wrong. Typical: 1-3 tablets, 2-20 mL injections, 20-250 mL/hr for IV.
  • 🔢
    Rounding rules: Round only at the final step — never mid-calculation. Express to 1 or 2 decimal places unless the question specifies. 41.67 drops/min → 42 drops/min (round to nearest whole drop).
  • ⚠️
    Unit conversion errors kill marks: Is the dose in mg but the stock in mcg? Convert first. Is time in minutes but you need hours? 30 min = 0.5 hr. This is the most common exam mistake.
  • 💡
    The "Want ÷ Got × Quantity" shortcut: Works for ALL tablet, capsule, and liquid calculations. Dose required ÷ Dose available × Volume/Quantity. Memorise this as your default formula.
  • ⏱️
    Time management: Calculation questions take longer. Skip if stuck and return. They are typically worth more marks. 3 minutes per calculation question is the GCC exam average.
  • 📱
    No calculator in most GCC exams: Practice mental arithmetic and long division. Learn to simplify fractions. 750/500 = 3/2 = 1.5 — much faster than long division.
  • 🔄
    Check your drop factor: 20 gtt/mL for standard adult IV, 60 gtt/mL for microdrip/paediatric. Using the wrong one means a completely wrong answer.
  • 📋
    GCC exam difficulty: Calculations are typically Steps 3-4 difficulty. Expect basic doses, IV rates, weight-based calculations. ICU drips may appear in specialist nursing exams.
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10 Rights of Medication Administration

Every medication administration requires verification of all 10 rights. This is tested on all GCC licensing exams.

1
Right Patient
2
Right Drug
3
Right Dose
4
Right Route
5
Right Time
6
Right Reason
7
Right Response / Effect
8
Right Documentation
9
Right Education
10
Right to Refuse
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High-Alert Medication Calculation Guide

HIGH ALERT Heparin Infusion — Weight-Based Protocol (80kg patient)
Step 1 — Bolus dose: 80 units/kg × 80 kg = 6,400 units IV bolus
Step 2 — Initial infusion: 18 units/kg/hr × 80 kg = 1,440 units/hr
Stock: 25,000 units/50mL = 500 units/mL
Rate = 1,440 ÷ 500 = 2.88 mL/hr ≈ 2.9 mL/hr
Double-check required: Two nurses independently verify dose, concentration, and pump setting before starting.
HIGH ALERT Insulin Infusion — DKA Protocol (70kg patient)
Step 1 — Fixed rate infusion: 0.1 units/kg/hr × 70 kg = 7 units/hr
Step 2 — Calculate pump rate: Stock: 50 units in 50mL = 1 unit/mL
Rate = 7 units/hr ÷ 1 unit/mL = 7 mL/hr
Monitoring: Capillary BGL hourly. Target: 6-10 mmol/L. Adjust per protocol. Check K⁺ before starting — hypokalaemia is dangerous with insulin.
HIGH ALERT Potassium Chloride — Peripheral IV (max rate example)
Maximum peripheral rate: 10 mmol/hr via peripheral IV (40 mmol/hr via CVC with monitoring)
Calculation: Available: 20 mmol/10mL KCl concentrate (MUST be diluted — never give undiluted)
For 10 mmol: take 5 mL KCl → add to 100mL NS → infuse over 1 hour = 105 mL/hr pump rate
Safety: Concentrated KCl is a NEVER EVENT if given undiluted IV push. Always stored separately. Two-nurse check mandatory.
HIGH ALERT Morphine PCA — Program Verification
Typical PCA settings to verify:
Concentration: 1 mg/mL (standard)
Bolus dose: 1 mg (1 mL)
Lockout interval: 5–10 minutes
4-hour limit: 20–30 mg (20–30 mL)
Background infusion: 0 (usually none for opioid-naive patients)
Check: 1. Pump programmed correctly. 2. Concentration label matches. 3. Patient education given. 4. Naloxone available at bedside.
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Resources & Further Practice

Recommended Apps (GCC)

MedCalc — clinical calculators
NurseMD — nursing drug guide
Medscape Drug Reference — comprehensive, available GCC App Store
Calculate by QxMD — evidence-based

Reference Books

Shann Drug Doses — essential for ICU nurses
British National Formulary (BNF) — comprehensive
Taber's Cyclopedic Medical Dictionary
Nursing Drug Handbook (Lippincott)

GCC Exam Strategy

Calculation questions: 8-15% of DHA/SCHS/QCHP exams
Difficulty level: Steps 3-4
Practice 5 calculations/day for 4 weeks before exam
Always verify units first in every question

Study Plan

Week 1: Basic dose calculations (tablets, liquids)
Week 2: IV rates and drip calculations
Week 3: Weight-based and paediatric doses
Week 4: ICU drips, timed revision and mock tests