Drug side effects Flashcards
Gaviscon - magnesium salts cause one & aluminium salts the other
Magnesium salts - diarrhoea
Aluminium salts - constipation
H2 antagonists (ranitidine)
Few side effects
PPIs (omeprazole)
GI disturbances, headaches
Anti-diarrhoeals (loperamide)
GI - constipation, abdominal cramps, flatulance
Loperamide does not penetrate CNS so no opioid toxicity or dependence
Laxatives (senna)
GI - diarrhoea, abdominal pain/cramps
Aminosalicylates (mesalazine)
GI - nausea, dyspepsia
Headache
Anti-emetics (domperidone)
Most common = diarrhoea
Loop diuretics (furosemide)
Losses of water & electrolytes:
-Dehydration
-Hypotension
-Low electrolyte states (increased urinary losses of sodium, potassium, chloride)
Other:
-Hearing loss & tinnitus (same co-transporter regulates endolymph composition)
Thiazide diuretics (bendroflumethiazide)
-Hyponatreamia & hypokalaemia
-Increased plasma glucose, LDL, triglycerides
Other:
-Impotence
Potassium-sparing diuretics (spironolactone)
Uncommon at low doses
Dizziness, hypotension & urinary symptoms only seen when used with other diuretics
B-blockers (atenolol)
Fatigue Coldness of the extremities Sleep disturbances with nightmares Glycaemic disturbances (affects carbohydrate metabolism) Headache
Calcium channel blockers (amlodipine)
Common: headache, palpitations, ankle oedema, flushing
Verapamil commonly causes constipation
ACEi (Ramipril)
Common:
- Hypotension (particularly after first dose)
- Persistent dry cough (increased levels of bradykinin which is usually inactivated by ACE)
- Hyperkalaemia (lower aldosterone level promotes K+ retention)
- Renal failure (especially if patient has renal artery stenosis)
ARBs (losartan)
-Hypotension (particularly after first dose)
-Hyperkalaemia (lower aldosterone level promotes K+ retention)
-Renal failure (especially if patient has renal artery stenosis)
NO COUGH - do not inhibit ACE
Nitrates (GTN, ISMN)
Vasodilation - flushing, headaches, light-headedness, hypotension
Cardiac glycosides (digoxin)
Bradycardia, dizziness
Visual disturbance (blurred yellow vision)
GI disturbance
Anti-dysrhythmics (amiodarone)
Hypotension during IV infusion
Anti-platelets (aspirin)
GI - irritation, ulceration
Haemorrhage
Hypersensitivity reactions, e.g. bronchospasm
Tinnitus (in regular high dose therapy)
Thrombolytics (clopidogrel)
Most common - bleeding
Common - GI upset
Rare - thrombocytopenia
Heparins (LMWH - enoxaparin)
Most common - bleeding (lower risk with fondaparinux)
Injection site reactions
Rare - thrombocytopenia
Oral anti-coagulants (warfarin)
Most common - bleeding (fine therapeutic index)
Slight excess = risk of bleeding from existing abnormalities or following minor trauma
Large excess = can trigger spontaneous haemorrhage
Novel anticoagulants (rivaroxaban)
GI - abdominal pain, constipation, diarrhoea, dyspepsia, N&V Dizziness, headache Hypotension Pruritis, rash Pain in extremeties
Statins (simvastatin)
Generally safe & well tolerated:
- Most common = headache, GI disturbances
- More serious = myopathy, rhabdomyolysis
- Rise in liver enzymes, e.g. ALT
B2 agonists (salbutamol)
Activation of β2 receptors - Tachycardia, palpitations, anxiety & tremor
Increased serum glucose concentration – promote glucogenolysis
Rise in serum lactate levels
Muscle cramps
Anticholinergics (tiotropium)
Uncommon as low systemic absorption Dry mouth (inhalation)
Tricyclic antidepressants (amitriptyline)
Blockade of receptors causes:
-mACh - dry mouth, constipation, urinary retention, blurred vision
-H1, a1 - sedation, hypotension
-D2 - breast changes, sexual dysfunction, extrapyramidal symptoms (tremor, dyskinesia)
Other:
Cardiac - arrhythmias, ECG changes
Brain - convulsions, hallucinations, mania
Overdose of amitryptiline
Severe hypotension, arrhythmias, convulsions, coma, respiratory failure
Sudden withdrawal of amitriptyline
GI upset, neurological & flu-like symptoms, sleep disturbance
SSRIs (citalopram)
GI upset, appetite, weight changes
Suicidal thoughts & behaviour might be increased
Hypersensitivity reactions
Hyponatraemia - confusion, reduced consciousness
Sudden withdrawal of SSRIs
GI upset, neurological & flu-like symptoms, sleep disturbance
Serotonin syndrome (high doses, overdose, combination with other antidepressant) = triad of…
- Autonomic hyperactivity
- Altered mental state
- Neuromuscular excitation
Benzodiazepines (diazepam)
Drowsiness, sedation, coma (dose dependent)
Dependence if used for more than a few weeks
Withdrawal reaction if abrupt cessation (similar to alcohol)
Overdose of benzodiazepines
Airway obstruction caused by loss of airway reflexes
NSAIDs (diclofenac)
GI toxicity
Renal impairment
Increased risk of CV events
Opioids (morphine)
N&V - activates chemoreceptor trigger zone (settles with use) Respiratory depression Euphoria & detachment Pupillary constriction Neurological depression (at high doses) Vasodilation & sweating Itching, urticaria
Withdrawal reaction of morphine
Anxiety, pain, breathlessness, pupil dilation, cool dry skin with piloerection (cold turkey)
I.e. opposite to clinical effects
Opioids (codeine)
Nausea, constipation
Dizziness & drowsiness
Neurological & respiratory depression
Anaphylaxis if given IV - never do this!!!!!
Which pain killers should never be given IV due to anaphylaxis?
Codeine + dihydrocodeine
Dopaminergic drugs
Nausea, drowsiness, confusion, hallucinations, hypotension
Wearing-off effect - symptoms worsen towards the end of the dosage interval of L-dopa
What is the ‘on-off effect’ with DAergic drugs?
Increasing the dose/frequency of L-dopa can partially overcome the wearing off effect, but this can have the opposite effect and cause dyskinesias (excessive & involuntary movements)
Phenytoin (4)
- Changes in appearance - skin coarsening, acne, hirsutism, gum hypertrophy
- Neurological effects - cerebellar symptoms + impaired cognition
- Haematological disorders - osteomalacia
- Hypersensitivity - mild or life-threatening
Overdose of phenytoin
Death through CV collapse & respiratory depression
Sodium valproate (5)
- GI upset
- Neurological - tremor, ataxia, behavioural
- Haematological - thrombocytopenia
- Transient increases in liver enzymes
- Hypersensitivity reactions - hair loss or life-threatening
Carbamazepine (4)
- GI upset
- Neurological - dizziness, ataxia
3, Hypersensitivity (10%) - mild rash - Oedema & hyponatraemia due to ADH effect
Anti-epileptic hypersensitivity syndrome (1 in 5000) - phenytoin, sodium valproate, carbamazepine
Usually occurs within 2 months of starting treatment
Features: SJS skin reaction or ttoxic epidermal necrolysis, fever, lymphadenopathy and systemic involvement
Paracetamol
At treatment doses it is very safe
Paracetamol overdose
The toxic metabolite that paracetamol is metabolised to (NAPQI) accumulates and causes hepatocellular necrosis
Treatment for paracetamol overdose
Glutathione precursor (acetylcysteine) - this conjugates with the toxic metabolite NAPQI to allow elimination, thereby preventing accumulation
Allopurinol
Generally well tolerated
Most common AE = skin rash (mild or serious)
Even though it is a gout preventative, starting allopurinol for the first time can worsen an acute attack of gout
