PSA Flashcards
what does the p450 enzyme system do?
metabolises drugs to INACTIVATE THEM
what are the effects of P450 inducers and inhibitors
INDUCERS- induce P450 system resulting in REDUCED rug concentrations
INHIBITORS- inhibit P450 syetm
P450 INDUCERS
PC BRAS
phenytoin
carbamezapine
barubiturates
rifampicin
alcohol (chronic)
sulfonylureas
P450 INHIBITORS
AODEVICES
allopurinol
omeprazole
disulfaram
erythromycin
valproate
insoniazide
ciprofloxacin
ethanol (acute)
sulphanomides
drugs to stop before surgery
I LACK OP
Insulin - variabe
Lithium- day before
Anticoagulants- variable
COCP/HRT- 4 weeks before
K- sparing diuretics/ Acei
Oral hypoglycaemics
Perindopril
key contraindications anticoagulant
no platelets/ anticoagulants in patients bleeding, at risk of bleeding or suspected of bleeding
what drug increases the anticoagulant effect of warfarin
erythryomycin (P450 inhibitor)
when is sodium chloride contraindicated in fluid replacement?
- hypernatraemia or hypoglycaemia (5% dextrose)
- ascites (human albumin solution)
- shocked from bleeding (blood transfusion)
maximum rate of IV K+
NEVER MORE than 10mmol/hour
prescribing maintenance fluids adults
1L 0.9% NaCl + 40mmol/kg over 8 hours
antiemetics of choice
nauseated:
REGULAR cyclizine 50mg 8 hourly IM/IV/ORAL
not nauseated:
PO cyclizine 50mg up to 8 hourly iM/IV/ORAL
nauseated/ not nauseated + heart failure
METOCLOPRAMIDE 10mg up to 8 hourly IM/IV/oral
not cyclizine causes fluid retention
what is the maximum daily dose of paracetamol
4g/day
max paracetamol dose in patients <50kg
500mg 6 hourly (2g/day)
which 2 drugs when used together can cause AKI
ACEi and NSAIDs
give examples of antimuscarinics
Atropine (e.g. for bradycardia)
Bronchodilator (e.g. ipratropium bromide, tiotropium)
Urge incontinence (e.g. oxybutynin)
mechanism of action antimuscarinics
block acetylcholine binding of nictoninic receptors to SUPPRESS the parasympathetic nervous system
side effects antimuscarinics
dry mouth, sore throat
dry eyes, pupillary dilatation
tachucardia
constipation, urinary retention
confusion, disorientation
drugs to consider confusion in the elderly
- OPIOIDS
- cyclizine
- diazepam
which drugs increase the risk of methotrexate toxicity
NSAIDs
what does co-dydramol 10/500 mean
500 mg paracetamol, 10mg codeine
when is methotrexate contraindicated
- ACTIVE INFECTION
- ASCITES
- IMMUNODEFICIENCY SYNDROMES
- significant pleural effusion
correct route of administration for insulin
SC (apart from sliding scales using a short acting insulin- IV)
drugs to continue pre-surgery
- cardiac or anti-hypertensives (except ACEi, ARBs, diuretics)
- epilepsy + Parkinson’s drugs
- asthma/ COPD inhalers
- PPIs
- Thyroid medication
- antidepressants
- regular steroids
- immunosuppressants + cancer drugs
drugs to stop pre-surgery
ACE i
ARBs
diuretics
anticoagulants + antiplatlets
HRT + COCP (stop 4 weeks before)
Lithium
NSAIDs
antidiabetic medications and surgery
adult daily fluid requirements
1mmol/kg K+/Na+/Cl- daily
50-100g glucose/day
25-30 ml/kg water daily
what important safety information should be given for each of the oral hypoglycaemic agents
outline the key information for psychiatric drugs
give examples of drugs with a narrow therapeutic index and therefore require monitoring
lithium, phenytoin, digoxin, theophylline
abx (gentamicin and vancomycin)
features of digoxin toxicity
confusion, nausea, visual halos, arrythmias
features of lithium toxicity
- coarse tremor (a fine tremor is seen in therapeutic levels)
- hyperreflexia
- acute confusion
- polyuria
- seizure
- coma
- arrythmias
how is gentamicin dosed
by weight:
typical regime is high dose 5-7mg/kg once daily
if renal failure: divided dosing
1mg/kg 12 hourly
endocarditis: divided dosing
1mg/kg 8 hourly
what is interesting about montiorign gentamicin levels
dose is never changed, just the duration between dose
e.g. switch to 36 or 48 hourly dosing, or withhold if VERY high levels
explain the metabolism of paracetamol
metabolised by gluthionine in the liver
in overdose, gluthionine is overwhelmed resulting in build up of toxic NAPQI
how does N=-acetylcysteine work
replenishes stores of gluthionine in the liver
management paracetamol overdose
if presenting <1hour: activated charcoal
give N-acetylcysteine:
- if above treatment line on normogram
- staggered dose
- presentation 8-12 hours post overdose with >150mg/kg ingested
- >24 hours if hepatic dysfunction
warfarin targets
general: 2.5
recurrent thromboembolism on warfrin: 3.5
prosthetic mitral valve: 3.5
prosthetic aortic vakve: 3.0
effect of NSAIDs on the kidneys
NSAIDs inhibit prostaglandin synthesis
prostaglandins normally cause afferent arteriole dilation, so NSAIDs reduce dulation of afferent arteriole- threfore CONTRAINDICATED IN RENAL ARTERY STENOSIS
List some drugs that affect renal blood flow.
ACE inhibitors - reduce efferent arteriolar constriction
NSAIDs - decreased afferent arteriolar constriction
Calcineurin inhibitors - decrease afferent arteriolar constriction
Diuretics - affect tubular funciton and decrease preload
digoxin is contraindicated in
BRADYCARDIA
what are the 2 form of available lithium
lithium citrate and lithium carbonate= NOT DOSE EQUIVALENT
how should lithium be monitored?
12 hours post dose
after dose change:
weekly until levels stabilised. Then every 3 months for first year, every 6 months after that
plasma concentration lithium
0.4-1mmol/L
what does lithium monitoring entail once established on tx
measure weight, U&Es, Ca, TFTs 6 monthly
ECG finding digoxin toxicity
reverse tick phenomenon
when is dogixin tocity made worse
in states of hypokalaemia,
when should digoxin levels be checked?
6 hours post dose
when should digoxin dose be halved?
concurrent use with amiodarone, dronedarone and quinine
switch IV to oral route digoxin
dose may beed to be increased by 20-33% to maintain same plasma concentration
what can carbimazole cause
ACUTE PANCREATITIS, NEUTROPAENIA, angranulocytosis,
statins and transaminases
at 3 month blood test if transaminases are <3X upper limit, no change needs to be made to statin therapy
outline azathioprine monitoring
monitor FBC weekly for first 4 weeks, then 3 ,monthly
what limits the use of amiodarone
very long half-life (20-100 days). For this reason, loading doses are frequently used
should ideally be given into central veins (causes thrombophlebitis)
has proarrhythmic effects due to lengthening of the QT interval
interacts with drugs commonly used concurrently (p450 inhibitor) e.g. Decreases metabolism of warfarin
numerous long-term adverse effects (see below)
MOA amiodarone
class IIII antiarrythmic
monitoring amiodarone
TFT, LFT, U&E, CXR prior to treatment
TFT, LFT every 6 months
adverse effects amiodarone
thyroid dysfunction: both hypothyroidism and hyper-thyroidism
corneal deposits
pulmonary fibrosis/pneumonitis
liver fibrosis/hepatitis
peripheral neuropathy, myopathy
photosensitivity
‘slate-grey’ appearance
thrombophlebitis and injection site reactions
bradycardia
lengths QT interval
hyponatraemia correction limit
no more than 10mmol/L over 24 hours
hyponatraemia medications to hold
thiazide
if on PPI switch to famotidine
which drugs require a dose reduction in renal impairment
morphine, gabapentin, gliclazide
when should ACEi be given
night time (can cause postural hypotension)
when can bisphosphonates be deprescribed?
there is no evidence for treatment beyond 10 years; management of these
patients should be on a case-by-case basis with specialist input as appropriate
patient develops HTN on COCP
The progesterone-only pill
(mini-pill, POP) is a suitable alternative as it is classified as safe for use in hypertensive patients, or
patients who have developed hypertension secondary to COCP use
main side effect CCB
peripheral oedema
side effects cyclizine
sedative antihistamien with antimuscarinic effects
oxygen prescription for hypercapnic COPD patient
Oxygen 28 % Venturi mask continuous
at what plasma level is lithium toxicity shown
> 1.5 mmol/L
what can precipitate lithium toxicity
- dehydration
- renal failure
- drugs: diuretics (especially thiazides), ACE inhibitors/angiotensin II receptor blockers, NSAIDs and metronidazole
when should ramiprim be withheld
when a patient is acutely unwell/ with reduced oral intake
when should antiplatelet agents be withheld
7 days before surgery
when should nitrofurantoin be avoided?
renal impairment
what is the max dose of citalopram in the elderly
10mg PO OD
which drugs are dosed in micrograms
levithyroxine, tamulosin, digoxin, colchicine, naloxone, fludrocortisone, inhalers, GTN spray, ipratropium
which drugs are dosed in high 00s (mg)
some abx, metformin, some antiepileptics
which drugs are dosed in grams
paracetamol, lithium, NAC, calcium carbonate
outline common drugs and frequencies
morning: diuretics and steroids
night: statins, sedatives
activity: parkinson’s
meals: insulin/ creon
weekly: methotrexate, folic acid, patches, bisphosphonates
which drugs are taken PR
laxatives, diclofenac, diaxepam
which drugs are taken SC
LMWH and insulin
which drugs cause oral candidiasis
steroids, abx, immunosuppressants
mx orla thrush
nyastin drops
adults emegrnecy resus fluids
0,9% NaCl 500ml over 15 mins
emergency hypoglycaemia fluids
100ml 20% glucose over 15 mins
emrgency hypokalaemia fluids
1000 ml NaCL 0.9%/ 0.3% KCl over 4 hours
emergency hypercalcaemia fluids
1000ml 0.9% NaCl over 4 hours
adults maintenance fluids without losses
0.9% NaCl/ 0.3% KCl 1L over 8 hours
5% glucose/ 0.15% KCl 1L over 8 hours
adults maintenance fluids with losses
use upper limit of water replacement (30ml/kg) over 4-6 hours
paediatric emergency fluid bolus
10ml/kg over 10 mins 0.9% saline
paediatric maintenance fluids
<10kg: 100ml/kg
<20: 50ml/kg
every kg >20: 20ml/kg
NaCl 0.9%/ 5% glucose
rate equations
rate (volume-per-time) = dose per time/ concentration
rate = dose/ time
drugs needing dose adjustment in CKD
abx (gentamicin, vancomycin, cephalosporin, penicillins)
digoxin
atenolol
methotrexate
sulfonylureas
furosemide
opioids
drugs to avoid in renal failure
NSAIDSs
lithium
abx (nitrofurantoin, tetracycline)
metformin
drugs to stop AKI
diuretics, aminoglycosides/ ACEi, metformin, NSAIDs
examples of COCP and POP
COCP- microgynon 30
POP- cerazette (deogestrel)
names of emergency contraception
evonorgestrel (levonelle)
Ullipristal (EllaOne)
antocoagulants and monitoring
LMWH: anti factor 10x
unfractionated: aPTT
DOAC: not required
warfarin: INR
anticoagulants and reversal agents
LMWH/ unfractionated heparin: protamine sulphate
dabigatran- adarucizuman
apixiban/ ribaroxaban- adnexanet alpha
warfarin- vitamin K agonist/ PCC
HRT continuous or sequential
sequential if amenorrhoeic <1 year
continuous if amenorrhoeic >1 year
HRT combined name
oestradiol with norethisterone (elleste duet) - tablet
evorelle conti/ evorelle sequi (PATCH)
oestrogen only HRT
oestradiol (elleste solo)
rapid acting insulin
novorapid (insulin aspart)
short acting insulin
actrapid (insulin human)
intermediate acting insulin
isoform insulin
long acting insulin
levemir (insulin determir)
lantus (insulin glargine)
mixed insulin (biphasic)
novomix
confusion, falls, gout, osteoporosis, hypertension, high cholesterol drug causes
electrolyte imbalance causes
drugs to stop intercurrent illness
metformin, statins, gliflozins (SGLT-2)
drugs to stop if trying to conceive
isotretinoin, methotrexate, warfarin
DOACs and surgery
48h, clopidogrel 7 days, warfarin (brudging plan)
drugs worsening parkinsons, mG, psoriasis, heart failure
hypo and hyperglycaemia drug causes
drug causes constipation and diarrhoea
drug causes urinary retention and incontinence
what drugs commonly cause dyspepsia
steroids and bisphosphontes
drugs causing bradycardia
bisoprolol and digoxin
which drugs cause oedema
CCBs and naproxen
drugs causing nasal congestion
selegiline and prazocin
NSAIDs avoided in
previous MI
common side effect of all insulins
oedema
fluids on the day of surgery diabetes
1000ml over 12 hours of
management of opioid induced constipation
combination of stimulant and osmotic laxative
doxycyclien efficacy reduced by
ferrous sulphate
drug causes of hypertension
steroids
monoamine oxidase inhibitors
the combined oral contraceptive pill
NSAIDs
leflunomide
drugs that may worsen osteoporosis
SSRIs
antiepileptics
proton pump inhibitors
glitazones
long term heparin therapy
aromatase inhibitors e.g. anastrozole
mx opioid induced constipation
combination: stimulant + osmotic laxative
calcium and ferrous sulphate intake
should NOT be taken together: calcium should be taken 1 h before ferrour or 2h after
major side effects quinolones
TENDON DISORDERS
cataract surgery (risk of intra-operative floppy iris syndrome);
TAMULOSIN
T2DM hba1c target
<48
diabetic meds
ROUTE for vaginal pessary
PV
fluid to start with nariable rate insulin infusion
dose for creams
X applications, topical
what drugs can cause hyperuricaemia
thiazide diuretics, aspirin, ticagrelor
arrythmia + hypotension drug
digoxin
best SSRI with cardiac comorbidity
sertraline
directions for administering GTN spray
take while sitting down, can cause hypotension
fluid deficit children equation
Fluid deficit (mL) = % dehydration x weight (kg) x 10
cholestatic drugs
fluclox
co-amox
nitrofurantoin
steroids
sulphonylureas
fusidic acid
relationship between FiO2 and PaO2
PaO2 should be Fio2-10
tamoxifen and warfarin
increases efficacy- HIGH INR
statin monitoring
rfx: CK baseline
no risk factors: alt
STATIN major drug reaction
statin + macrolide
patient takign lithium develops hypertension, which medicatiin
CCB (do not choose ace, arb, thiazides, loop)
gentamicin dosing changes
high post 1 hour PEAK: reduce dose
high pre-dose (trough): increase interval
why is trimethoprim contraindicated with methotrexate use
both are FOLATE antagonists
what group of patients should DPP4 and GLP-1 agonists be avoided in?
those at increased risk of pancreatitis
what drugs commonly cause thrombocytopaenia
penicillins
examples of POP
traditional: (missed pill= >3h late)
- micronor, noriday
other: (missed pill >12h late)
- cerazette (desorgestrel)
MOA POP
traditional: thickens cervical mucus
cerazette: inhibits ovulation
colchicine contraindicated in acute gout with patients taking which medication
STATINS (increased risk myopathy)
oestrogen only contraceptives
elleste solo (oral)
evorel (transdermal) - first line if BMI >30
PV oestrogen gel
sandrena
adjunct prohesterones for HRT
lNG IUS
medroxyprogesterone acetate
1st line oral and transdermal HRT combined
sequential:
transdermal: evorel sequi
oral: elleste duel
continuous:
transdermal: evorel conti
oral: kilovance
(oestradiol and norethisterone)
contraindications for laxatives
stimulant: bowel obstruction
osmotic: bloating
bulk forming: faecal impaction
mx of statins in statin myopathy
stop statin
remeasure CK
if CK returns to normal, continue at lower dose
first line for painful diabetic neuropathy
duloxetine
diretic to be given if rewuired when patient on lithium
furosemide (ACEi/arb, NSAIDs CI with lithium use)
prescription for rapid relief of heartburn
magesium carbonate
drugs causing pancreatitis
S - Steroids
T - Thiazides (e.g., hydrochlorothiazide)
E - Estrogens
R - Rifampin (and other anti-tuberculosis drugs)
O - Opiates (e.g., codeine, morphine)
I - Immunosuppressants (e.g., azathioprine, mercaptopurine)
D - Diuretics (especially furosemide)
S - Sulfa drugs (e.g., sulfasalazine, sulfamethoxazole)
V - Valproate (and other antiepileptic drugs)
I - Isotretinoin (and other retinoids)
P - Pentamidine (used for pneumonia treatment in immunocompromised patients)
which drugs are contraindicated in asthma
beta blockers, NSAIDs, ACE i
