Pharmacology Flashcards
What do you need to remember about naloxone?
1/2 life only minutes (may need infusion/repeat doses)
Pt will go crazy (security?)
Pt will be in pain
Lowers pt seizure threshold
What is amiodarone?
Class II anti-arrhythmic K+ channel blocker Used in chemical cardioversion Prolong QT interval Inhibits hepatic enzymes (be careful if used with digoxin)
What is flecainide?
Na+ channel blocker
Class I C anti-arrhythmic
What is sotalol?
Non cardio-selective ß-blocker
Class III anti-arrhythmic (rhythm control)
Prolongs QT interval
Renally excreted
What is verapamil?
Non-dihydropyridine Ca2+ channel blocker Class IV anti-arrhythmic Hepatic metabolism Can cause AV block Rate limiting
What receptors does noradrenaline work on?
+++ alpha-1
+++ alpha-2
+ ß1
What receptors does adrenaline work on?
+++ alpha-1
++ alpha-2
+++ ß1
++ ß2
What receptors does dopamine work on?
\++ alpha-1 \+ alpha-2 \++ ß1 \+++ ß2 \+++ DA
What receptors does dobutamine work on?
+ alpha-1
+++ ß1
+ ß2
What receptors does isoproterenol work on?
++ ß1
++ ß2
Why is verapamil and bisoprolol a bad combination?
Verapamil causes AV block
Combined with ß-blocker-> bradycardia
What is ciprofloxacin?
A quinolone Abx Broad spectrum (gram+ and -) Gram -ve sepsis, skin, UTI, resp Can be used in penicillin allergy (instead of tazocin) SE: thrush, D&V, MRSA promotion
Issues with metformin in an acute patient?
Can potentiate hypoglycaemia Raises lactate (confuses clinical picture)
Warfarin and diclofenac co-prescription is bad because:
Both highly protein bound, compete with eachother, more free drug
Diclofenac also causes gastritis, warfarin can cause bleeding-> GI bleeds
What drugs should not be combined in someone with renal issues?
NSAIDs, ACEi and betablockers
Causes of poor pain relief
- Inadequate assessment
- Poor choice of analgesic
- Incorrect dose
- Wrong frequency (24hr clock)
- Wrong mode of delivery (eg orally in a pt with an ileus)
What is the 1st step in the WHO analgesia ladder?
Paracetamol
NSAID
What is the 2nd step in the WHO analgesia ladder?
Weak opioid (codeine)
Paracetamol
NSAID
What is the 3rd step in the WHO analgesia ladder?
Strong opioid
Paracetamol
NSAID
What is the 4th step in the WHO analgesia ladder?
Nerve block
Epidurals
PCA pump
Spinal stimulators
What is the proper name for paracetamol?
Acetaminophen
Dose of paracetamol
1g/6hrly in adults >50kg
60mg/kg/day max if <50kg
90mg/kg/day max in children
SE of NSAIDs
COX-2 SE-> platelet function (increases risk of bleeding), gut mucosal damage (peptic ulceration), renal impairment, bronchospasm.
Contraindications of NSAIDs
Allergy, asthma, GI upset, coagulopathy, renal impairment, CVS disease
Why is effect of codeine variable?
Metabolism varies between individuals with codeine via CYP2D6. Oral only. Synergism with paracetamol.
What opioid is best in renal failure
Fentanyl (doesn’t accumulate)
Which opioid is best in obstetrics
Pethidine
Which opioid is better tolerated that codeine?
Oxycodone
SE of opioids
n&v, bradycardia, pruritis, constipation, dizziness, sedation, hallucinations, respiratory depression, tolerance/dependence/addiction.
What is a PCA?
Patient controlled anaesthesia
Syringe driver with button (locks off for 5 mins)
Fentanyl/oxycodone/morphine
Contraindications to local anaesthetics
Patients refusal, shock, sepsis, coagulopathy, neuro disease
What are other meds used for pain relief
Amitriptyline & gabapentin for neuropathic pain
Ketamine
Clonidine
Entonox (for procedures, rapid)
Contraindications to entonox
Pneumothorax
Bowel obstruction
Air embolus
Define MRSA
Meticillin, flucloxicillin resistant staph aureus
De-colonisation treatment is given to eradicate is esp pre operatively, if admitted to a ward, in susceptible patients.
What predisposes someone to C.diff?
- Broad spectrum/cephalosporin antibiotic use
- Bowel surgery
- PPI use
- Malnutrition
- TPN
Treatment of C.diff
Metronidazole
Complicated: Vancomycin/fidaxomycin orally for 14 days
Complications of C.diff
Can develop into toxic megacolon/pseudomembranous colitis
What antibiotics should be avoided in 1st trimester of pregnancy?
Co-trimoxazole, trimethoprim, rifampicin
Tetracyclines
Quinolones
What abx should be avoided in 2nd and 3rd trimester of pregnancy?
chloramphenicol, co-trimoxazole, nitrofurantoin, rifampicin
Tetracyclines
Quinolones
How much Na is required per day?
1-2mmol/kg/day
When would a fit person die with water and no food?
60 days
What should be taken into consideration when prescribing maintenance fluid?
- Age
- Weight
- Co-morbidity, eg heart failure
- Clinical situation (well/ill)
- Medications
- Anticipated ‘nil by mouth’ period
How much potassium is needed per day?
0.7-1mmol/kg/day
How many calories are needed per day (baseline)
25kCal/kg/day
How much chloride is needed?
Same at sodium
1-2mmol/kg/day
What fluid is used to treat hypoglycaemia in diabetes?
20% dextrose + insulin
When is fluid loss ‘pure water’?
Fever, dehydration, hyperventilation
What do you become deficient in with vomiting and NG tube loss?
Chloride
Potassium
H+
= metabolic alkalosis
What do you become deficient in with biliary drainage loss
Na+
K+
Cl-
HCO3-
What do you become deficient in with inappropriate urinary loss
K+
H+
(variable)
Diarrhoea loss?
Na+
K+
HCO3-
When should fluids be given in a pt with ileus?
1L every 12hrs through 3rd space losses if you have a paralytic ileus.
Cautious about reintroduction of fluids, due to pooling of fluid, vomiting and aspiration. 24-48hrs after, wait for bowels to open.
