key knowledge Flashcards
which drugs increase enzyme activity and thus reduce drug concentration?
PC BRAS drugs…
Phenytoin, carbamazepine
Barbituates (like phenobarbital used for seizures)
Rifampacin
Alcohol
Sulphonylureas (gliclazide)|
which drugs are enzyme inhibitor, and thus cause an increase in drug concentration?
AO DEVICES
Allopurinol, Omeprazole
Disulfram- used in alcohol dependency Erythromycin Valposarte Isonizid Ciprofloxacin Ethanol Sulphonamides (e.g. trimethoprim)
which drugs should be increased for surgery?
patients with adrenal atrophy should double their steroid dose ‘sick day rule’
at induction of anasthesia patients are given IV steroid to avoid profound hypotension
which drugs should be stopped before surgery?
I LACK OP
insulin- variable
Lithium- a day before
Anticoagulants/antiplatelets- variable
COCP- 4 weeks before
K- sparing diuretics and ace inhibitors- day of surgery
oral hypogylcaemics
perindopril- (ace inhibitor- so day of surgery?)
how is addisonian crisis treated?
100mg IV hydrocortisone
what are features of digoxin toxicity?
- confusion
- nausea
- visual halos
- arrhythmia
what are features of lithium toxicity?
- tremor
- tiredness
- arrhythmia
- seizure
- coma
- diabetes insipidus
what are features of phenytoin toxicity?
gum hypertrophy
ataxia
nystagmus
how is over anticoagulation with warfarin managed?
if INR < 6 then reduce warfarin dose
6-8- omit warfarin for 2 days
> 8 omit warfarin and give 1-5mg of oral vitamin K
if INR >5 give IV instead of oral vitamin K 1-3 mg
if there is a major bleed causing hypotension or a bleed into a confined space like the brain or the eye then give 5-10mg IV vitamin K
who should metaclopramide be avoided in?
- Parkinson’s disease
- young women- put them at risk of dystonias
why can trimethoprim not be used alongside methotrexate?
they are both folate antagonists and can lead to bone marrow toxicity
why is methotrexate held if a patient has an infection?
they may be septic and it needs to be withheld pending exclusion of neutropenic sepsis
