Table of Contents
Groups of side effects
- Anticholinergic: dilated pupils, blurred vision, dry mouth, flushed skin, urinary retention, constipation
- Tricyclic antidepressants, antihistamines, hyoscine, atropine, antipsychotics, incontinence medications
- Antihistaminergic: weight gain, sedation
- Tricyclic antidepressants, antipsychotics, antihistamines
- Anti-α-adrenergic: postural hypotension, sexual dysfunction, nasal congestion, headache
- Tricyclic antidepressants, antipsychotics, α-blockers
- Antidopaminergic: extrapyramidal side effects (e.g. tardive dyskinesias, parkinsonism), hyperprolactinaemia (→ galactorrhoea, oligomenorrhea, subfertility), neuroleptic malignant syndrome, oculogyric crisis
- Metoclopramide, antipsychotics
Side effects to memorise
TB drugs
- Rifampicin: orange-red tears/urine + hepatitis
- Isoniazid: neuropathy + hepatitis
- Pyrazinamide: + hepatitis
- Ethambutol: optic neuritis
Antiepileptics
- Phenytoin: toxicity (→ cerebellar syndrome), acne, coarse face, gum hypertrophy, hirsutism + inhibit COCP
- Carbamazepine: rash, dizziness, hyponatraemia, hair thinning + inhibit COCP
- Sodium valproate: tremor, weight gain, hair thinning + teratogenic (avoid if child-bearing age)
- Lamotrigine: rash (Stevens-Johnson syndrome)
Antidepressants
- SSRI (e.g. fluoxetine, citalopram, sertraline): nausea, low libido, withdrawal, insomnia, hyponatraemia
- Tricyclic antidepressant (e.g. amitriptyline): [anticholinergic effects], [antihistaminergic effects], [anti-α-adrenergic effects], hyponatraemia (SIADH), arrhythmias
- Monoamine oxidase A inhibitors (e.g. selegiline): 3Hs – Hypertension, Hepatocellular jaundice, Hyperthermia
Antihypertensives
- ACE inhibitors: dry cough, postural hypotension, acute kidney injury in renal artery stenosis (check U&Es before and 2 weeks after starting), angioedema of the tongue, hyperkalaemia, profound hypotension when started
- Ca2+ blocker: pedal oedema, headache/flushing/dizziness
- β-blocker: diabetes risk, impotence, bradycardia, fatigue, cold hands and feet, sleep disturbance
- α-blocker: [anti-α-adrenergic effects]
Diuretics
- ALL: dehydration, hypotension, hyperuricaemia, hypokalaemia (except K+ sparing), hyponatraemia, hypomagnesaemia
- Loop: hypocalcaemia (used in treatment of hypercalcaemia)
- Thiazide (e.g. indapamide): hypercalcaemia
- K+ sparing: hyperkalaemia, gynaecomastia
DMARDs
- Sulfasalazine: myelosuppression, oligospermia, hepatitis, rashes (Stevens-Johnson syndrome, erythema nodosum), renal problems, discoloured urine
- Chloroquine: retinopathy, tinnitus, myopathy
- Methotrexate: hepatic toxicity, pulmonary toxicity, myelosuppression, mucositis
- TNF antagonists: infusion reactions (including anaphylaxis), infections (including TB reactivation), autoimmune reactions, blood disorders
- Cyclophosphamide: haemorrhagic cystitis, myelosuppression, alopecia
Hypoglycaemics
- Insulin: hypoglycaemia, fat-hypertrophy at injection site, hypokalaemia (used in treatment of hyperkalaemia), weight gain
- Metformin: weight loss, lactic acidosis, metallic taste, GI disturbance, B12 deficiency
- Sulphonylureas (e.g. gliclazide): hypoglycaemia, weight gain
- Thiazolidinediones (glitazones, e.g. pioglitazone): fluid retention (→ heart failure, oedema), hepatotoxicity, fractures
- DPP4-inhibitors (gliptins, e.g. sitagliptin): pancreatitis
- SGLT2-inhibitors (flozins, e.g. empagliflozin): UTIs/thrush, risk of DKA, weight loss, may increase risk of amputations
Contraception
See here.
Antipsychotics
- ALL: [antidopaminergic effects], [anticholinergic effects], [antihistaminergic effects], [anti-α-adrenergic effects]
- Clozapine: agranulocytosis
- Chlorpromazine: cholestatic jaundice
- Haloperidol: prolonged QT interval, interference with temperature regulation
Antiarrhythmics
- Amiodarone: thyroiditis, pulmonary fibrosis, peripheral neuropathy, myopathy, blue-grey skin pigmentation/photosensitivity, hepatitis, metallic taste
- Digoxin toxicity: xanthopsia (yellow/orange tinge to vision), GI distress, any arrhythmia
- Adenosine: flushing, sense of impending doom
Others
- Lithium: toxicity (tremor/ataxia/dysarthria → coma, convulsions, hypotension), diarrhoea, hypothyroidism, diabetes insipidus
- Steroids: diabetes risk, cushingoid appearance, psychosis, osteoporosis, hypokalaemia, hyperglycaemia, infections, leukocytosis, risk of avascular necrosis
- Azathioprine: myelosuppression
- Ciclosporin: tremor, chronic interstitial nephritis, hypertrichosis, gum hyperplasia, burning sensation in hands/feet
- Levodopa: nausea, red urine/other body fluids, postural hypotension, dyskinesias, ‘on-off’ and ‘wearing off’ effects
- Proton pump inhibitor: tinnitus, GI disturbance, headache, hyponatraemia, hypomagnesaemia
Drugs causing…
Electrolyte imbalances
- Hypernatraemia: sodium-containing antibiotics/fluids, sodium bicarbonate, drugs causing diabetes insipidus (e.g. lithium)
- Hyponatraemia: antidepressants, diuretics, chlorpromazine, carbamazepine, proton pump inhibitors, ACE inhibitors
- Hyperkalaemia: K+ sparing diuretics, ACE inhibitors/angiotensin receptor blockers, NSAIDs, trimethoprim, ciclosporin/tacrolimus, heparin
- Hypokalaemia: salbutamol (used in Tx of hyperkalaemia), insulin, diuretics (except K+ sparing), caffeine/theophylline
- Hypercalcaemia: thiazide diuretics, lithium
- Hypocalcaemia: loop diuretics, bisphosphonates, phenytoin
Organ toxicity
- Hepatitis: TB antibiotics (rifampicin/isoniazid/pyrazinamide), sodium valproate, methotrexate, methyldopa, amiodarone, statins, paracetamol, phenytoin, ketoconazole/fluconazole, nitrofurantoin, sulfonylureas/sulfonamides
- Cholestasis: co-amoxiclav (may be delayed/severe), clarithromycin/erythromycin, carbamazepine, chlorpromazine, contraceptives, flucloxacillin, sulfonylureas/sulfonamides
- Pulmonary toxicity/fibrosis: nitrofurantoin, amiodarone, methotrexate, cyclophosphamide, sulfasalazine, bleomycin
- Renal impairment
- Interstitial nephritis: NSAIDS, penicillins/cephalosporins, calcineurin inhibitors (ciclosporin/tacrolimus), PPIs
- Acute tubular necrosis: lithium, contrast, gentamicin, amphotericin B
- Precipitate renal artery stenosis: ACE inhibitors
- Glomerular damage: NSAIDs
- Creatinine rise: trimethoprim, cimetidine/ranitidine
- Photosensitivity: tetracyclines, terbinafine, chlorpromazine, amiodarone (→ blue/grey discoloration), chemo (vincristine), ciprofloxacin, psoralens, retinoids, thiazide diuretics, sulphonylureas
- Hypothyroidism: amiodarone, carbimazole, lithium, propylthiouracil, radio-iodine
Other reactions
- Stevens-Johnson syndrome/erythroderma: sulphur-based drugs (sulphonamides, sulfonylureas), antiepileptics, allopurinol, antibiotics
- Vasculitis: allopurinol, penicillin, sulphonamides, thiazides, phenytoin, cephalosporins
- Agranulocytosis: C’s – Carbamazepine, Clozapine, Colchicine, Carbimazole, Cytotoxic agents
- Gynaecomastia: DISCO MTV – Digoxin, Isoniazid, Spironolactone, Cimetidine, Oestrogens, Methyldopa/metronidazole, Tricyclic antidepressants, Verapamil
- Neuropathy: metronidazole, nitrofurantoin, isoniazid, vincristine, cisplatin, amiodarone, phenytoin
- Megaloblastic anaemia: methotrexate, phenytoin, ethanol, trimethoprim, sulfonamides, sodium valproate, metformin, antidepressants
- Dyskinesia: dopaminergic drugs (levodopa, bromocriptine), dopamine-blocking drugs (antipsychotics), antidepressants
- Clostridium difficile risk: cephalosporins, clindamycin, ciprofloxacin, broad spectrum penicillins
