PSA: adverse drug reactions Flashcards
what drugs should be used with caution in asthmatics
- beta blockers
- NSAIDs
- adenosine
NSAIDs and asthmatics?
Around 10-20% of patients with asthma experience bronchospasm / worsening of asthma control after ingesting NSAIDs. The risk is increased in patients with nasal polyps and also those who are middle-aged. Surprisingly, NSAID-induced asthma is uncommon in children.
If alternative analgesics are not available and there is no history of hypersensitivity to NSAIDs it is acceptable to give asthmatic patients a trial of NSAIDs after informing them of the risks.
beta blockers and asthmatics?
beta-blockers may cause bronchospasm and are best avoided. They are not however absolutely contraindicated and if no alternatives are available a low-dose may be initiated under specialist supervision. Some beta-blockers are more cardioselective (e.g. nebivolol) so in theory may induce less bronchospasm.
adenosine and astmatics?
The BNF states that asthma / chronic obstructive pulmonary disease (COPD) are contra-indications to adenosine. Verapamil may be used as an alternative.
what medications may exarcebate heart failure
The following medications may exacerbate heart failure:
thiazolidinediones
- pioglitazone is contraindicated as it causes fluid retention
verapamil
negative inotropic effect
NSAIDs/glucocorticoids
should be used with caution as they cause fluid retention
low-dose aspirin is an exception - many patients will have coexistent cardiovascular disease and the benefits of taking aspirin easily outweigh the risks
class I antiarrhythmics
flecainide (negative inotropic and proarrhythmic effect)
what drugs are known to be harmful in pregnancy
Antibiotics
tetracyclines
aminoglycosides
sulphonamides and trimethoprim
quinolones: the BNF advises to avoid due to arthropathy in some animal studies
Other drugs
ACE inhibitors, angiotensin II receptor antagonists
statins
warfarin
sulfonylureas
retinoids (including topical)
cytotoxic agents
The majority of antiepileptics including valproate, carbamazepine and phenytoin are known to be potentially harmful.
what drugs can worsen seizure control in epileptics
The following drugs may worsen seizure control in patients with epilepsy:
alcohol, cocaine, amphetamines
ciprofloxacin, levofloxacin
aminophylline, theophylline
bupropion
methylphenidate (used in ADHD)
mefenamic acid
Some medications such as benzodiazepines, baclofen and hydroxyzine may provoke seizures whilst they are being withdrawn.
Other medications may worsen seizure control by interfering with the metabolism of anti-epileptic drugs (i.e. P450 inducers/inhibitors).
what drugs exarcerbate psoriasis
drugs: beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
withdrawal of systemic steroids
