Essential Paramedic Pharmacology Revision Guide

Why Pharmacology Matters for UK Student Paramedics

Pharmacology is one of the most challenging and most critical components of any paramedic degree programme. In the pre-hospital environment, you are often the first — and sometimes the only — clinician a patient sees. Understanding not just what drugs you carry, but why you give them, how they work, and what can go wrong, is the difference between competent practice and genuinely excellent care.

This revision guide is designed for student paramedics in the UK working towards their BSc (Hons) Paramedic Science degree or preparing for clinical placement. It follows the JRCALC (Joint Royal Colleges Ambulance Liaison Committee) clinical guidelines framework used across NHS ambulance trusts.

Core Pharmacological Principles You Must Know

Before drilling into specific drugs, you need a solid grasp of the foundational principles that underpin all of paramedic pharmacology.

Pharmacokinetics: What the Body Does to a Drug

Remember the acronym ADME:

• Absorption – How a drug enters the systemic circulation. Routes used by paramedics include IV (fastest, 100% bioavailability), IM, intranasal, sublingual, and oral. In haemorrhagic shock, IM absorption is unreliable due to vasoconstriction.
• Distribution – How a drug spreads through body compartments. Lipid-soluble drugs cross the blood-brain barrier more readily. Volume of distribution (Vd) affects loading doses.
• Metabolism – Primarily hepatic (first-pass effect). Relevant when comparing oral vs IV routes for the same drug.
• Excretion – Mostly renal. Important when considering drug accumulation in elderly patients or those with renal impairment — a common pre-hospital scenario.

Pharmacodynamics: What the Drug Does to the Body

Pharmacodynamics covers receptor interactions, dose-response relationships, and therapeutic windows. Key concepts include:

• Agonists – Bind to and activate receptors (e.g., salbutamol on beta-2 receptors).
• Antagonists – Bind to but block receptors (e.g., naloxone blocking opioid receptors).
• Therapeutic index – The ratio between a toxic dose and an effective dose. Drugs with a narrow therapeutic index (e.g., digoxin) require careful consideration in overdose presentations.

Key Drug Classes in the JRCALC Formulary

UK paramedics carry a defined set of medications under their scope of practice. The following drug classes appear most frequently in degree assessments and OSCEs.

Analgesics

• Methoxyflurane (Penthrox) – Inhaled analgesic. Rapid onset, self-limiting due to self-administration. Maximum 6 mL per episode, no more than 15 mL per week. Contraindicated in renal impairment and altered consciousness.
• Morphine – Strong opioid. IV/IM. Causes histamine release — monitor for hypotension. Titrate carefully in elderly patients. Antagonised by naloxone.
• Paracetamol (IV) – Often underestimated. 1g IV over 15 minutes for adults. Reduces opioid requirements when used as part of multimodal analgesia.

Cardiovascular Drugs

• Aspirin – 300 mg PO for suspected STEMI or ACS. Irreversibly inhibits COX-1, reducing thromboxane A2-mediated platelet aggregation.
• Adrenaline (Epinephrine) – Used in cardiac arrest (1 mg IV/IO every 3–5 minutes after initial cycles) and anaphylaxis (500 micrograms IM, anterolateral thigh). A common exam mistake is confusing the two doses.
• Atropine – Muscarinic antagonist. Used for symptomatic bradycardia. 500 micrograms IV, repeated to a maximum of 3 mg.
• Amiodarone – 300 mg IV/IO in refractory VF/pVT. A further 150 mg may be given after further shocks.

Respiratory Drugs

• Salbutamol – Beta-2 agonist. 5 mg nebulised for acute asthma or COPD exacerbation. Causes bronchodilation and can cause tachycardia and hypokalaemia with repeated doses.
• Ipratropium bromide – Muscarinic antagonist. Used alongside salbutamol in severe asthma. 500 micrograms nebulised.
• Hydrocortisone – IV corticosteroid for severe asthma and anaphylaxis. Slow onset — not a frontline drug for acute management but important for preventing biphasic reactions.

Drugs Used in Altered Consciousness and Overdose

• Naloxone – Competitive opioid antagonist. 400 micrograms IV/IM/intranasal. Titrate to adequate respiratory effort, not full consciousness. Half-life shorter than most opioids — reassessment and repeat dosing may be needed.
• Glucagon – Used in hypoglycaemia when IV access cannot be established. 1 mg IM. Less effective in malnourished or alcohol-dependent patients due to depleted glycogen stores.
• Glucose 10% – Preferred over glucose 40% in current UK practice due to vein preservation and reduced osmotic injury.

Practical Tips for Pharmacology Exams and OSCEs

Pharmacology questions in paramedic assessments tend to test application, not just recall. Here is how to approach your revision strategically:

1. Learn drugs in clinical context – Revise each drug alongside the clinical presentation it treats. Don't study adrenaline in isolation; study it within anaphylaxis and cardiac arrest scenarios.
2. Understand contraindications mechanistically – Rather than memorising lists, ask why a drug is contraindicated. Morphine in head injury was historically avoided due to concerns about masking neurological signs and causing pupillary changes — understanding the reasoning helps it stick.
3. Use drug cards – Create concise reference cards covering: indication, mechanism, dose, route, contraindications, and side effects. Keep them to one side of A5.
4. Cross-reference with JRCALC – Always anchor your learning to the current JRCALC guidelines. Exam questions are written with this document as the gold standard.
5. Practice calculations regularly – Drug dose calculations are a core OSCE skill. Practice weight-based dosing, infusion rates, and unit conversions until they are automatic.

Common Mistakes to Avoid

Student paramedics consistently lose marks — and more importantly, risk patient safety — through a handful of recurring errors:

• Confusing adrenaline doses for anaphylaxis vs cardiac arrest
• Forgetting to reassess after administering naloxone
• Overlooking contraindications in patients with polypharmacy
• Assuming IV is always the best route without considering clinical context
• Failing to document administration accurately and contemporaneously

Building a Sustainable Revision Habit

Pharmacology rewards consistency over cramming. Aim to review a small number of drugs each day rather than attempting to cover the entire formulary the week before an exam. Active recall techniques — such as writing out drug profiles from memory and then checking them — significantly outperform passive reading. Spaced repetition, clinical scenario practice, and peer teaching are all evidence-based strategies that work well for this type of content.