Pharmacology Flashcards
Time passed since ingestion for paracetamol levels?
4 hours
How long is NAC infused over & why?
1 hour to reduce anaphylactoid reaction (non-IgE mediated mast cell release)
King’s College Hospital criteria for liver transplantation (paracetamol liver failure)
Arterial pH < 7.3, 24 hours after ingestion
or all of the following:
prothrombin time > 100 seconds
creatinine > 300 µmol/l
grade III or IV encephalopathy
Contraindications to viagra
patients taking nitrates and related drugs such as nicorandil
hypotension
recent stroke or myocardial infarction (NICE recommend waiting 6 months)
What are the adverse effects of Gentamicin?
Ototoxicity & Nephrotoxicity
Contraindication - myasthenia gravis
Drugs causing lung fibrosis
- amiodarone
- cytotoxic agents: busulphan, bleomycin
- anti-rheumatoid drugs: methotrexate, sulfasalazine
- nitrofurantoin
- ergot-derived dopamine receptor agonists (bromocriptine, cabergoline, pergolide)
Adverse effects of macrolides e.g erythromycin
Prolongation of the QT interval
Why should statins be stopped when taking macrolides?
Increases the risk of myopathy and rhabdomyolysis
Recommend Adult Life Support (ALS) adrenaline doses
anaphylaxis: 0.5mg - 0.5ml 1:1,000 IM
cardiac arrest: 1ml of 1:1000 IV
Inducers of the P450 system
antiepileptics: phenytoin, carbamazepine
barbiturates: phenobarbitone
rifampicin
St John’s Wort
chronic alcohol intake
griseofulvin
smoking (affects CYP1A2, reason why smokers require more aminophylline)
Inhibitors of the P450 system include
antibiotics: ciprofloxacin, erythromycin
isoniazid
cimetidine,omeprazole
amiodarone
allopurinol
imidazoles: ketoconazole, fluconazole
SSRIs: fluoxetine, sertraline
ritonavir
sodium valproate
acute alcohol intake
quinupristin
Adverse effects of Quinolones (ciprofloxacin, levofloxacin)
lower seizure threshold in patients with epilepsy
tendon damage (including rupture) - the risk is increased in patients also taking steroids
cartilage damage has been demonstrated in animal models and for this reason quinolones are generally avoided (but not necessarily contraindicated) in children
lengthens QT interval
Contraindications of Quinolones (ciprofloxacin, levofloxacin)
women who are pregnant or breastfeeding
avoid in G6PD
Which 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)
Side effects of amiodarone
Thyroid issues, pulmonary fibrosis, corneal deposits, photosensitivity reactions and derangement in liver function tests.
Most common side effects of Rifampicin
Orange bodily fluids, rash, hepatotoxicity, drug interactions
Most common side effects of Isoniazid
Peripheral neuropathy, psychosis, hepatotoxicity
Most common side effects of Pyrazinamide
Arthralgia, gout, hepatotoxicity, nausea
Most common side effects of Ethambutol
Optic neuritis, rash
Most important reason in giving HRT to younger women
Preventing the development of osteoporosis
Other benefits include a reduced incidence of colorectal cancer
Why is oestrogen combined with progestogen in a woman with a uterus?
to reduce the risk of endometrial cancer
Investigations prior to TB therapy?
LFTs
Visual acuity and renal function should also be checked prior to starting ethambutol
What complication may be prevented by the co-prescription of pyridoxine?
The risk of peripheral neuropathy with isoniazid can be reduced by prescribing pyridoxine
Signs of lithium toxicity
Features of toxicity
coarse tremor (a fine tremor is seen in therapeutic levels)
hyperreflexia
acute confusion
polyuria
seizure
coma
Toxicity may be precipitated by:
dehydration
renal failure
drugs: diuretics (especially thiazides), ACE inhibitors/angiotensin II receptor blockers, NSAIDs and metronidazole
Side effects of ACE inhibitors
Cough
Hyperkalaemia
Side effects of Bendroflumethiazide
Gout
Hypokalaemia
Hyponatraemia
Impaired glucose tolerance
Side effects of Calcium channel blockers
Headache
Flushing
Ankle oedema
Side effects of Beta-blockers
Bronchospasm (especially in asthmatics)
Fatigue
Cold peripheries
Side effects of Doxazosin
Postural hypotension
Side effects of Sulfonylureas e.g. Glicazide
Hypoglycaemic episodes
Increased appetite and weight gain
Syndrome of inappropriate ADH secretion
Liver dysfunction (cholestatic)
Side effects of Gliptins
Pancreatitis
Side effects of Glitazones
Weight gain
Fluid retention
Liver dysfunction
Fractures
Drug-induced urinary retention
tricyclic antidepressants e.g. amitriptyline
anticholinergics e.g. antipsychotics, antihistamines
opioids
NSAIDs
disopyramide
Drugs which can precipitate digoxin toxicity
drugs: amiodarone, quinidine, verapamil, diltiazem, spironolactone (competes for secretion in distal convoluted tubule therefore reduce excretion), ciclosporin. Also drugs which cause hypokalaemia e.g. thiazides and loop diuretics
Harmful drugs antibiotics i pregnancy
Antibiotics
tetracyclines
aminoglycosides
sulphonamides and trimethoprim
quinolones: the BNF advises to avoid due to arthropathy in some animal studies
Harmful drugs in pregnancy
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. The decision to stop such treatments however is difficult as uncontrolled epilepsy is also a risk
Drugs causing photosensitivity
thiazides
tetracyclines, sulphonamides, ciprofloxacin
amiodarone
NSAIDs e.g. piroxicam
psoralens
sulphonylureas
Amoxicillin S/E
Rash with infectious mononucleosis
Co-amoxiclav S/E
Cholestasis
Flucloxacillin S/E
Cholestasis (usually develops several weeks after use)
Erythromycin S/E
Gastrointestinal upset
Prolongs QT interval
Ciprofloxacin S/E
Lowers seizure threshold
Tendonitis
Metronidazole S/E
Reaction following alcohol ingestion
Doxycycline S/E
Photosensitivity
Trimethoprim S/E
Rashes, including photosensitivity
Pruritus
Suppression of haematopoiesis
Drugs to avoid in renal failure
antibiotics: tetracycline, nitrofurantoin
NSAIDs
lithium
metformin
Teratogenic effect of Warfarin
Craniofacial abnormalities
Teratogenic effect of Valproate
Neural tube defects
Craniofacial abnormalities
Teratogenic effect of Thalidomide
Limb reduction defects
Teratogenic effect of Tetracyclines
Discoloured teeth
Teratogenic effect of smoking
Preterm labour
Intrauterine growth retardation
Teratogenic effect of Maternal diabetes mellitus
Maternal diabetes mellitus Macrosomia
Neural tube defects
Polyhydramnios
Preterm labour
Caudal regression syndrome
Teratogenic effect of Lithium
Ebstein’s anomaly (atrialized right ventricle)
Teratogenic effect of Diethylstilbesterol
Vaginal clear cell adenocarcinoma
Teratogenic effect of Cocaine
Intrauterine growth retardation
Preterm labour
Teratogenic effect of Chloramphenicol
‘Grey baby’ syndrome
Teratogenic effect of Carbamazepine
Neural tube defects
Craniofacial abnormalities
Chloramphenicol
Teratogenic effect of Aminoglycosides
Ototoxicity
Teratogenic effect of Alcohol
Craniofacial abnormalities
Teratogenic effect of Ace I
Renal dysgenesis
Craniofacial abnormalities
Drug-induced thrombocytopenia
Drug-induced thrombocytopenia (probable immune-mediated)
quinine
abciximab
NSAIDs
diuretics: furosemide
antibiotics: penicillins, sulphonamides, rifampicin
anticonvulsants: carbamazepine, valproate
heparin
Visual changes secondary to drugs
blue vision: Viagra (‘the blue pill’)
yellow-green vision: digoxin
Drugs causing ocular problems
Cataracts
steroids
Corneal opacities
amiodarone
indomethacin
Optic neuritis
ethambutol
amiodarone
metronidazole
Retinopathy
chloroquine, quinine
Sildenafil can cause both blue discolouration and non-arteritic anterior ischaemic neuropathy
Ecstasy poisoning features & management
Clinical features
neurological: agitation, anxiety, confusion, ataxia
cardiovascular: tachycardia, hypertension
hyponatraemia
this may result from either syndrome of inappropriate ADH secretion or excessive water consumption whilst taking MDMA
hyperthermia
rhabdomyolysis
Management
supportive
dantrolene may be used for hyperthermia if simple measures fail
Organophosphate insecticide poisoning features & management
Features can be predicted by the accumulation of acetylcholine (mnemonic = SLUD)
Salivation
Lacrimation
Urination
Defecation/diarrhoea
cardiovascular: hypotension, bradycardia
also: small pupils, muscle fasciculation
Management
atropine
the role of pralidoxime is still unclear - meta-analyses to date have failed to show any clear benefit
Tamoxifen adverse effects
menstrual disturbance: vaginal bleeding, amenorrhoea
hot flushes - 3% of patients stop taking tamoxifen due to climacteric side-effects
venous thromboembolism
endometrial cancer
Why is aspirin contraindicated in <16
Risk of Reye’s syndrome
