Pharmacology and Electrolytes Flashcards
What are the side effects of ACEi?
Cough (due to raised bradykinin levels)
Angioedema
Hyperkalaemia
First dose hypotension - more common in patients taking diuretics
When should ACEi be avoided?
Pregnancy and breastfeeding
Renovascular disease
Aortic stenosis
What are some causes of hyperkalaemia?
AKI
Drugs: ACEi, ARB, potassium sparing diuretics, spiranolactone
Metabolic acidosis
Addison’s disease
Rhabdomyolysis
Massive blood transfusion
What are the ECG changes seen in hyperkalaemia?
Tall tented T-waves
Small P waves
Widened QRS
Asystole
Ventricular fibrillation
how is hyperkalaemia treated?
IV 10ml 10% calcium gluconate
insulin/dextrose infusion
What are the ECG features of hypokalaemia?
U waves
small or absent T waves (occasionally inversion)
prolong PR interval
ST depression
long QT
What are some causes of hypokalaemia with alkalosis?
vomiting
thiazide and loop diuretics
Cushing’s syndrome
Conn’s syndrome (primary hyperaldosteronism)
What are some causes of hypokalaemia with acidosis?
diarrhoea
renal tubular acidosis
acetazolamide
partially treated diabetic ketoacidosis
What are some side effects of thiazide-like diuretics?
Hypokalaemia, hyponatraemia, hypercalcaemia
dehydration
postural hypotension
gout
impaired glucose tolerance
impotence
What are the types of calcium channel blockers?
Dihydropyridine (nifedipine, amlodipine) - vasodilation of peripheral blood vessels
Non-dihydropyridine (diltiazem, verapamil) - decrease heart rate and myocardial contractility
What are the side effects of dihydropyridines?
Symptoms caused by vasodilation of peripheral blood vessels
Short-acting dihydropyridines (e.g. nifedipine) can cause reflex tachycardia
Flushing
Headache
Ankle swelling
What are dihydropyridines used to treat?
Hypertension
Angina
Raynaud’s phenomenon
What is the difference between positive and negative inotropes?
Positive inotropes increase heart contractility
Negative inotropes decrease heart contractility
What are the indications for verapamil?
Angina, hypertension, arrhythmias - it is highly negatively ionotropic
What are the indications for diltiazem?
Angina, hypertension - less negatively ionotropic than verapamil
What are the contraindications and side effects of verapamil?
Use with beta-blockers can cause heart block
Heart failure
Constipation
Hypotension
Bradycardia
Flushing
What are the contraindications and side effects of diltiazem?
Hypotension
Bradycardia
Heart failure
Ankle swelling
What are the side effects of amiodarone?
Hypothyroidism and hyperthyroidism
Corneal deposits
Pulmonary fibrosis/pneumonitis
Liver fibrosis/hepatitis
Bradycardia
Lengthens QT
Photosensitivity
‘slate grey’ appearance
What are the adverse interactions of amiodarone?
Decreased metabolism of warfarin, therefore increased INR
increased digoxin levels
What are the side effects of beta blockers?
bronchospasm
cold peripheries
fatigue
sleep disturbances, including nightmares
erectile dysfunction
What are the contraindications for beta blockers?
uncontrolled heart failure
asthma
sick sinus syndrome
concurrent verapamil use: may precipitate severe bradycardia
What are the features of hypocalcaemia?
prolonged QTc interval
tetany: muscle twitching, cramping, spasm
perioral paraesthesia
Trousseau’s sign
Chvostek’s sign
what are the features of hypercalcaemia?
shortened QTc interval
hypertension
stones
depression
abdominal pain
how is hypercalcaemia treated?
rehydration with normal saline - typically 3-4l/day
following rehydration, bisphosphonates
furosemide if patients can’t handle aggressive fluid resuscitation
what are the contraindications for statins?
macrolides (e.g. clarithromycin, vancomycin)
pregnancy
what are the adverse effects of statins?
myopathy
liver impairment - check LFTs at baseline, 3 months and 12 months
?risk of intracerebral haemorrhage
what are the side effects of nitrates?
hypotension
tachycardia
headaches
flushing
what are the side effects of sodium valproate?
teratogenic
hair loss
weight gain
ataxia
tremor
GI: nausea
what are the side effects of lamotrigine?
Steven-Johnsons syndrome
what are the side effects of carbamazepine?
dizziness and ataxia
drowsiness
headache
visual disturbances (diplopia)
Steven-Johnson syndrome
hyponatraemia
what are the side effects of adenosine?
chest pain
bronchospasm
flushing
what are the causes of metabolic acidosis with normal anion gap?
GI bicarbonate loss
renal tubular acidosis
ammonium chloride injection
Addison’s disease
what are the causes of metabolic acidosis with raised anion gap?
raised lactate: sepsis, shocks, burns, hypoxia, metformin
ketones: DKA, alcohol
urate: renal failure
acid poisoning: salicylates, methanol
what are the causes of metabolic alkalosis?
vomiting/aspiration - vomiting can also lead to hypokalaemia
diuretics
hypokalaemia
primary hyperaldosteronism
Cushing’s syndrome
what are the causes of respiratory acidosis?
COPD, severe asthma
neuromuscular disease, e.g. myasthenia gravis, DMD
obesity hypoventilation syndrome
sedative drugs: benzodiazepines, opiate overdose
what are the causes of respiratory alkalosis?
anxiety leading to hyperventilation
pulmonary embolism
salicylate poisoning - mixed respiratory alkalosis and metabolic acidosis
CNS disorders: stroke, encephalitis
altitude
pregnancy
what are the side effects of metoclopramide?
extrapyramidal effects - acute dystonia
diarrhoea
hyperprolactinaemia
tardive dyskinesia
parkinsonianism
avoid in bowel obstruction!
what are the symptoms of hyponatraemia?
headache
lethargy
nausea, vomiting
dizziness
confusion
muscle cramps
late: seizures, coma, respiratory arrestt
how is chronic hypovolaemic hyponatraemia treated?
0.9% NaCl
if serum sodium rises, supports diagnosis of hypovolaemic hyponatraemia
if serum sodium falls, suggests SIADH
how is euvolaemic hyponatraemia treated?
fluid restrict to 500-1000mL/day
consider: vaptans (ADH receptor antagonist, increases diuresis), demeclocycline
how is hypervolaemic hyponatraemia treated?
fluid restrict tot 500-1000mL/day
consider: vaptans, loop diuretics
how is acute hyponatraemia treated?
hypertonic saline (3% NaCl)
what are the complications of hyponatraemia management?
central pontine myelinolysis due to over-correction of severe hyponatraemia
irreversible symptoms:
dysarthria
dysphagia
paraparesis
seizures
confusion
coma
