Side Effects and Interactions Flashcards
What are some common side effects of statins (like atorvastatin)?
ARTHRALGIA, MYALGIA, MYOSITIS, nausea and vomiting, flatulence, constipation, GI discomfort
What must you check before starting a patient on statins?
Lipid profile, triglyceride concentrations, liver function tests (LFTs), thyroid stimulating hormone (TSH) and renal function
What must you check during statin treatment, and how often?
LFTs repeated three monthly and at 12 months. If >3 times the upper limit of normal, stop atorvastatin therapy.
What is a concern in a patient taking statins who develops severe unexplained muscle pain (more than normal myalgia)?
Rhabdomyolysis
What drug do statins commonly interact withand what effect does this have?
Macrolide antibiotics like clarithromycin - macrolides inhibit CYP450 enzymes in the liver, increasing the exposure to statins. This can trigger rhabdomyolysis.
What are some common side effects of levothyroxine if given in excess?
Anxiety, restlessness, flushing, sweating, fine tremors, diarrhoea, nausea and vomiting
What monitoring is required for patients taking levothyroxine, and how often?
TFT every 3 months until stable, then once yearly
How can you manage the effects of excess levothyroxine?
Can reduce the dose
Can advise patients to take levothyroxine in the morning, 30 minutes before breakfast and drinks containing caffeine (absorption is reduced by food and caffeine)
What can levothyroxine interact with?
Antacids, calcium, and iron supplements can affect absorption of levothyroxine
What are some common side effects of PPIs like omeprazole?
Nausea & vomiting, stomach pain, constipation and flatulence
What are some long term risks of PPIs like omeprazole? (including electrolyte imbalances)
Increased risk of osteoporosis, Clostridium difficile infection, hypomagnesaemia and vitamin B12 deficiency
What are some common interactions with PPIs like omeprazole?
SSRIs - increases SSRI exposure as both are metabolised by the same enzyme
Clopidogrel - reduces it’s effectiveness as both are metabolised by the same enzyme (weirdly lansoprazole isn’t??)
Methotrexate - inhibits renal excretion of methotrexate so increases exposure
What are some common side effects of calcium channel blockers?
Dizziness, flushing, palpitations, headaches, peripheral oedema (leg swelling)
(You can work it out if you think about what might happen as a result of vasodilation)
What monitoring is required when patients take CCBs?
Regular blood pressure checks
It’s important to check that they don’t become too hypotensive if they’re on multiple anti-hypertensives
What can amlodipine interact with?
Simvastatin - both inhibit the same enzyme which increases simvastatin levels, and increases risk of rhabdomyolysis
What are the common side effects of ACE inhibitors like ramipril? (including electrolyte imbalances)
A dry cough due to bradykinin accumulation (change to ARBs!)
Hyperkalemia due to inhibition of aldosterone synthesis
Hypotension
What is a serious side effect of ACE inhibitors like ramipril and how should it be managed?
Angioedema - it can compromise the airway so ACE inhibitors should be stopped immediately