Pharmacology Notes for Nursing: Drug Classes, Antidotes, Calculations and High-Alert Drugs

These pharmacology notes for nursing collect the drug facts that nursing recruitment exams ask again and again: pharmacokinetics, drug class suffixes, antidotes, emergency drugs, dose calculations, insulin, antibiotics, anticoagulants, side effects and vaccine cold chain. They are written for quick revision before AIIMS NORCET, staff nurse, CHO and ANM exams, based on standard texts such as KD Tripathi and nursing pharmacology references.

Pharmacology questions are rarely about obscure drugs. Most test whether a nurse can give a common drug safely: the right dose, the right monitoring and the right response to a side effect or overdose.

Scope of pharmacology notes for nursing exams

In NORCET and nursing officer exams, pharmacology appears both as direct questions and inside clinical scenarios from medical-surgical, obstetric and paediatric nursing. Drug calculations and high-alert medication questions are common. Read this page with the medical surgical nursing notes, where many of these drugs are used, and the anatomy and physiology notes for nursing, which explain the receptors and organs these drugs act on.

Pharmacokinetics basics

• Absorption, Distribution, Metabolism, Excretion (ADME): what the body does to the drug. Pharmacodynamics is what the drug does to the body.
• Bioavailability: fraction of the dose reaching systemic circulation; 100 percent for IV drugs.
• First-pass metabolism: oral drugs pass through the liver before reaching the circulation. Nitroglycerin is given sublingually to bypass it.
• Half-life: time for plasma concentration to fall by half. Steady state is reached after about 4 to 5 half-lives.
• Therapeutic index: ratio of toxic dose to effective dose. Narrow-index drugs (digoxin, lithium, phenytoin, warfarin, aminoglycosides) need level monitoring.
• The liver is the main site of metabolism (cytochrome P450 enzymes); the kidney is the main route of excretion, so doses are adjusted in liver and renal failure.

Drug classes and suffixes

Suffix or class	Examples	Key nursing point
-olol (beta blockers)	Atenolol, metoprolol, propranolol	Check pulse and BP; can mask hypoglycaemia; avoid non-selective ones in asthma
-pril (ACE inhibitors)	Enalapril, ramipril	Dry cough, angioedema, hyperkalaemia
-sartan (ARBs)	Losartan, telmisartan	Used when ACE inhibitor cough occurs
-dipine (calcium channel blockers)	Amlodipine, nifedipine	Ankle oedema, headache, flushing
-statin	Atorvastatin, rosuvastatin	Report muscle pain (myopathy); monitor liver function
-prazole (proton pump inhibitors)	Pantoprazole, omeprazole	Give before breakfast
Loop diuretics	Furosemide	Hypokalaemia, ototoxicity with rapid IV doses; give in the morning
Potassium-sparing diuretics	Spironolactone	Hyperkalaemia, gynaecomastia
-azepam / -zolam (benzodiazepines)	Diazepam, lorazepam, midazolam	Sedation, respiratory depression; antidote flumazenil
-sone / -olone (corticosteroids)	Hydrocortisone, prednisolone, dexamethasone	Hyperglycaemia, infection risk; never stop long-term therapy abruptly

Antidotes table

Drug or poison	Antidote
Paracetamol	N-acetylcysteine
Opioids (morphine, pethidine)	Naloxone
Benzodiazepines	Flumazenil
Heparin	Protamine sulphate
Warfarin	Vitamin K (phytonadione); prothrombin complex concentrate or FFP for severe bleeding
Organophosphate poisoning	Atropine with pralidoxime
Digoxin	Digoxin-specific antibody fragments (Fab)
Iron	Desferrioxamine
Magnesium sulphate	Calcium gluconate (10 percent)
Insulin overdose	Dextrose; glucagon
Methanol	Fomepizole or ethanol
Cyanide	Hydroxocobalamin; sodium nitrite with sodium thiosulphate
Methaemoglobinaemia	Methylene blue
Anticholinergic (atropine) toxicity	Physostigmine
Lead	Calcium disodium EDTA, dimercaprol, succimer
Arsenic, mercury	Dimercaprol (BAL)
Methotrexate toxicity	Folinic acid (leucovorin)
Snake bite (envenomation)	Polyvalent anti-snake venom

Emergency drugs

Drug	Main use and standard adult dose
Adrenaline	Cardiac arrest: 1 mg IV every 3 to 5 minutes. Anaphylaxis: 0.5 mg IM of 1:1000 (1 mg/mL)
Amiodarone	Shock-refractory VF or pulseless VT: 300 mg IV, then 150 mg
Atropine	Symptomatic bradycardia: 1 mg IV, repeat every 3 to 5 minutes up to 3 mg
Adenosine	Stable narrow-complex SVT: 6 mg rapid IV push with flush, then 12 mg if needed
Naloxone	Opioid overdose with respiratory depression
Calcium gluconate 10 percent	Hyperkalaemia with ECG changes, hypocalcaemia, magnesium toxicity
Dextrose 25 or 50 percent	Hypoglycaemia
Magnesium sulphate	Eclampsia and severe pre-eclampsia

Magnesium sulphate (Pritchard regimen): loading dose 4 g IV (20 percent solution) plus 10 g deep IM (5 g of 50 percent in each buttock), then 5 g IM every 4 hours in alternate buttocks. Before each dose check that the knee jerk is present, respiratory rate is at least 16/min and urine output is at least 30 mL/hour (100 mL in 4 hours). Keep calcium gluconate ready.

Drug calculations

Formula	Use
Dose to give = (Desired dose / Dose available) x Volume	Tablets, syrups, injections
Drops/min = Volume (mL) x Drop factor / Time (min)	Gravity infusions
mL/hour = Total volume (mL) / Time (hours)	Infusion pumps
Young’s rule: Child dose = Age / (Age + 12) x Adult dose	Children 1 to 12 years
Clark’s rule: Child dose = Weight (lb) / 150 x Adult dose	Weight-based estimate

Worked example 1: Amoxicillin 500 mg is ordered; the syrup contains 250 mg in 5 mL. Dose = 500 / 250 x 5 = 10 mL.

Worked example 2: Dopamine 5 mcg/kg/min is ordered for a 60 kg patient, using 200 mg in 50 mL (4,000 mcg/mL). Dose per hour = 5 x 60 x 60 = 18,000 mcg. Rate = 18,000 / 4,000 = 4.5 mL/hour.

Worked example 3: Heparin 25,000 units in 500 mL gives 50 units/mL. For 1,000 units/hour, run at 20 mL/hour.

• 1 g = 1,000 mg; 1 mg = 1,000 mcg; 1 kg = 2.2 lb; 1 teaspoon = 5 mL.
• A 1 percent solution has 1 g in 100 mL. 1:1000 adrenaline = 1 mg/mL; 1:10,000 = 0.1 mg/mL.

IV drop factors, cannula sizes and fluids are explained in the fundamentals of nursing notes.

High-alert medications

High-alert medications (as listed by ISMP) can cause significant harm when used in error. Common examples are insulin, heparin and other anticoagulants, opioids, concentrated potassium chloride, hypertonic sodium chloride, neuromuscular blocking agents, chemotherapy drugs, IV sedatives such as midazolam and propofol, IV magnesium sulphate and IV oxytocin.

• Use independent double checks, standard concentrations and smart pumps.
• Store concentrated potassium chloride separately with warning labels; never give KCl as an IV push.
• Use the full word “units”, never “U”, to avoid ten-fold errors.

Insulin types

Type	Examples	Onset	Peak	Duration
Rapid-acting	Lispro, aspart, glulisine	About 10 to 15 minutes	About 1 to 2 hours	About 3 to 5 hours
Short-acting	Regular (soluble) insulin	About 30 to 60 minutes	About 2 to 4 hours	About 6 to 8 hours
Intermediate-acting	NPH (isophane)	About 1 to 2 hours	About 4 to 12 hours	About 12 to 18 hours
Long-acting	Glargine, detemir	About 1 to 2 hours	No marked peak	Up to about 24 hours

• Only regular insulin is given IV (for example in DKA).
• When mixing regular and NPH in one syringe, draw up clear (regular) before cloudy (NPH). Glargine is not mixed with other insulins.
• Store unopened vials in a refrigerator at 2 to 8 degrees C; never freeze. In-use vials can be kept at room temperature for the period stated by the manufacturer.
• Abdomen gives the fastest absorption; rotate sites to prevent lipohypertrophy.

Antibiotic classes

Class	Examples	High-yield adverse effect or nursing point
Penicillins, cephalosporins	Amoxicillin, ceftriaxone	Anaphylaxis: ask about allergy, observe after the first dose
Aminoglycosides	Gentamicin, amikacin, streptomycin	Nephrotoxicity and ototoxicity; monitor levels and renal function
Macrolides	Azithromycin, erythromycin	GI upset, QT prolongation
Tetracyclines	Doxycycline	Tooth discolouration; avoid in pregnancy and young children; not with milk or antacids
Fluoroquinolones	Ciprofloxacin, levofloxacin	Tendinitis and tendon rupture
Glycopeptides	Vancomycin	Red man syndrome with fast infusion (infuse over at least 60 minutes), nephrotoxicity
Nitroimidazoles	Metronidazole	Metallic taste, disulfiram-like reaction with alcohol
Chloramphenicol	Chloramphenicol	Grey baby syndrome, bone marrow suppression

Anti-TB drugs: isoniazid causes peripheral neuropathy (prevented with pyridoxine) and hepatitis; rifampicin turns urine and tears orange-red and reduces oral contraceptive effect; pyrazinamide raises uric acid; ethambutol causes optic neuritis (red-green colour vision loss); streptomycin damages the eighth cranial nerve. Programme details are in the national health programmes notes.

Anticoagulants

Drug	Route	Monitoring	Antidote
Unfractionated heparin	IV or SC	aPTT	Protamine sulphate
Low molecular weight heparin (enoxaparin)	SC	Routine monitoring usually not needed; platelets	Protamine (partial reversal)
Warfarin	Oral	PT/INR, usual target 2 to 3	Vitamin K
Dabigatran	Oral	Clinical; renal function	Idarucizumab

• Give SC heparin in the abdomen without aspirating or rubbing; do not expel the air bubble from prefilled enoxaparin syringes.
• Patients on warfarin should keep vitamin K intake (green leafy vegetables) consistent rather than stopping it.
• Heparin-induced thrombocytopenia: watch for a falling platelet count.

Common side effects asked in MCQs

Drug	Classic side effect or fact
Digoxin	Toxicity: nausea, bradycardia, yellow-green vision; hypokalaemia increases toxicity; check apical pulse first
Lithium	Narrow therapeutic range (about 0.6 to 1.2 mEq/L); tremor; toxicity worsened by dehydration and low sodium
Phenytoin	Gum hypertrophy, nystagmus, hirsutism
Morphine	Respiratory depression, constipation, pinpoint pupils
Atropine	Dry mouth, tachycardia, dilated pupils, urinary retention
Antipsychotics	Extrapyramidal symptoms; neuroleptic malignant syndrome
Clozapine	Agranulocytosis
Metformin	Lactic acidosis; withhold around iodinated contrast as per protocol
Sulfonylureas	Hypoglycaemia
Aspirin	Gastric bleeding; Reye’s syndrome in children
Oral iron	Black stools, constipation; liquid iron through a straw
Cyclophosphamide	Haemorrhagic cystitis (mesna protects)
Doxorubicin	Cardiotoxicity
Vincristine	Peripheral neuropathy
Thalidomide	Phocomelia (teratogenic)

Routes and storage

• IV route has the fastest onset and 100 percent bioavailability. Sublingual and buccal routes avoid first-pass metabolism.
• Transdermal patches (fentanyl, nitroglycerin): remove the old patch, rotate sites and avoid heat over the patch.
• Do not crush enteric-coated or sustained-release tablets.
• Protect light-sensitive drugs such as sodium nitroprusside by covering the infusion.
• Keep sublingual nitroglycerin tablets in the original airtight dark glass container.
• Narcotics are stored under double lock with a count register checked at each shift handover.

Vaccines and cold chain basics

• At the health facility level, vaccines under India’s Universal Immunization Programme are stored at 2 to 8 degrees C in an ice-lined refrigerator (ILR). Deep freezers are used to freeze ice packs.
• Freeze-sensitive vaccines (hepatitis B, pentavalent, DPT, Td, IPV, PCV) must never be frozen. The shake test is used to check suspected freezing.
• Heat-sensitive vaccines include OPV (the most heat-sensitive), measles-rubella and BCG.
• Vaccine vial monitor (VVM): use the vial if the inner square is lighter than the outer circle; discard if the inner square matches or is darker than the outer circle.
• Reconstituted BCG, measles-rubella and JE vaccines must be used within 4 hours of reconstitution and are discarded after the session.
• Vaccine carriers are packed with conditioned ice packs for outreach sessions.

The immunisation schedule is covered in the community health nursing notes and the pediatric nursing notes.

Quick revision points

1. Paracetamol overdose antidote: N-acetylcysteine.
2. Heparin antidote: protamine sulphate. Warfarin antidote: vitamin K.
3. Organophosphate poisoning: atropine and pralidoxime.
4. Magnesium sulphate toxicity antidote: calcium gluconate.
5. Check knee jerk, respiration and urine output before each magnesium sulphate dose.
6. ACE inhibitor classic side effect: dry cough.
7. Only insulin given IV: regular insulin.
8. Mixing insulin: clear before cloudy.
9. Ethambutol: optic neuritis. Rifampicin: orange body fluids.
10. Isoniazid neuropathy is prevented by pyridoxine.
11. Vancomycin rapid infusion: red man syndrome.
12. Aminoglycosides: ototoxic and nephrotoxic.
13. Digoxin toxicity is increased by hypokalaemia.
14. Warfarin is monitored by PT/INR; heparin by aPTT.
15. Adenosine is pushed rapidly followed by a flush.
16. 1:1000 adrenaline = 1 mg/mL.
17. Most heat-sensitive UIP vaccine: OPV.
18. VVM discard point: inner square matches or is darker than the outer circle.

Follow a full study plan with the NORCET preparation strategy. Concept RNA covers pharmacology in its AIIMS NORCET courses and staff nurse and nursing officer courses. Test calculations and drug facts with the NORCET test series and staff nurse test series, and download the free nursing PDF notes.

Frequently asked questions

How should I study pharmacology for nursing exams?

Learn by drug class rather than individual drugs, using suffixes, then memorise antidotes, emergency drugs and classic side effects. Practise calculations every week.

Which book is best for nursing pharmacology?

KD Tripathi’s Essentials of Medical Pharmacology is a standard reference in India. Nursing students can use a nursing pharmacology textbook for drug administration and nursing considerations.

Are drug calculation questions asked in NORCET?

Calculation questions such as dose, drip rate and infusion rate are a regular part of nursing exams. They are easy marks if you practise the formulae.

What is the safest way to remember antidotes?

Revise the antidote table in pairs, then test yourself both ways (drug to antidote and antidote to drug) with MCQs.