Prescribing Flashcards
dosing of isosorbide nitrate
needs a nitrate free interval so give both doses in the day (morning?)
drugs to stop before surgery
STOP NOW or I LACKOP
Insulin- go onto VRII (unless good glycaemic control (69 mmol/mol/ 8.5 % or less) and are undergoing minor procedure- insulin can be reduced to 80% day before and day of. or if on mixed then 50% on the day of)
Lithium (the day before)
Anticoagulants/antiplatelets variable (clopidogrel and aspirin 7 days before, anticoag 48 hours, warfarin 5 days)
COCP/HRT (4 weeks before)
K sparing diuretics (spiro, acei, amiolride)
Oral hypoglycaemics (metformin if taken 3x a day, sulphonlyurea omit mane dose or both doses if afternoon surgery and SGLT2 day of)
Perindopril and other ACE-I
Patients with a planned short starvation period (no more than one missed meal in total) should be managed by modification of their usual diabetes medication, avoiding VRIII wherever possible (although VRIII may be necessary if emergency surgery or in people with poorly controlled diabetes (HbA1c >69mmol/mol)). Patients expected to miss more than one meal should have VRIII if they develop hyperglycaemia (CBG >12mmol/L).
When prescribing replacement fluids also prescribe maintenance fluids….
Worked example: fluid replacement
A child who weighs 12kg is 5% dehydrated. Calculate their total fluid requirement over 24 hours:
Fluid deficit = 5% dehydration x 12 x 10 = 600 mL
Maintenance = 1000mL (100 mL/kg for first 10 kg) + 100mL (50 mL/kg for last 2kg) = 1100 mL
Total fluid requirement = 1100 mL + 600 mL = 1700 mL/24 hours » 71 mL/hour
if someone is oligouric how much mL do they need resus?
generally 500mL
if oligouric + tachycardia = 1L
If oligouric + tachy + shocked = >2L
Glucose-free balanced crystalloids (e.g. Hartmann’s solution) are recommended as initial …. fluids.
resus not replacement.
replacement as in the case of dehydration not acute a-e
for replacement Use isotonic crystalloid that contains sodium with added glucose (e.g. 0.9% sodium chloride + 5% glucose).
resus rate for kids
10 mL/kg over <10 minutes.
how to work how much replacement to give in kids. note replacement not resus.
work out how dehydrated they are using usual/recent actual weight vs what they are now.
generally if they are shocked we already assume 10% dehydration
we then use this formula to calcuate how much Fluid deficit (mL) they are in and how much we need to replace them by = 10% dehydration x weight (kg) x 10
how do you work out replacement and maintenance needs in kids
Replacement is used if you think theyre losing fluid
Maintenace is your bog standard
Using the replacement formula: ((well weight - current weight) / well weight )) x 100 , you find out the percentage dehydration they’re in. Shocked children are generally 10% dehydrated. Then you use this to work out how much fluid you have to give them. So if they’re 10% dehydrated, you do 10 x weight in kg x 10, and this is the total amount they need for that day (maintenace and replacement together as this formulae has accounted for their weight, ie. if they were 20kg it would come out as 2000mL , vs using the holliday segar maintenance formula which gives you 1000 + 500 = 1500mL)
If a patient is given resus boluses you dont need to subtract that from the total 24-hour fluid requirements.
Recognising ongoing abnormal fluid or electrolyte losses can allow you to tailor your fluid prescription to prevent later complications (e.g. hypokalaemia).
Consider the following sources of ongoing fluid or electrolyte loss:
Vomiting/NG tube loss
Diarrhoea
Stoma output loss (colostomy, ileostomy)
Biliary drainage loss
Sweating/fever/dehydration (reduced or absent oral intake)
Urinary loss (e.g. diabetes insipidus/post-AKI polyuria)
Vomiting/NG tube loss- Give more potassium and chloride
Diarrhoea- Give more potassium and sodium and bicarb (hartmanns with extra potassium??)
Stoma output loss (colostomy, ileostomy)- Give more sodium and chloride (hartmanns)
Biliary drainage loss- Give more sodium, bicarb and chloride
Sweating/fever/dehydration (reduced or absent oral intake)- Need more water usually pure water loss
Urinary loss (e.g. diabetes insipidus/post-AKI polyuria)- variable
cyclizine dose
50mg im/iv/po but contradincated in heart failure. remember this is preferred out of all antiemetics esp. in pregnacny for out patient prescriptions that need to be given >3/5 days (as metaclopramide wouldnt be ideal here).
metaclopramide dose
10mg im/iv/po but?parkinsons or young people (risk of dyskinesia espeically if over 5 days)
is it better to prescribe more opioid types or less?
less - prescribijng lots of different increases suscpetibility ot side effects so just do one brand/type
typical concentration of morphine used is
oral tablets 5-10mg smallest dose (5mg if MST, 10mg if sevredol or zomorph (most commonly used in Wales because they are cheaper than MST))
oral solution is 10 mg/5 mL so go to the nearest 5mg because if you do it by 2.5mg thats really difficult to dose (like 1.25mL)
gent vs vanc vs teico, When to measure and when to give.
TAKE U+E for everyone before starting.
GENT- trough levels 18-24hr after last (Given usually every 24hr, no need to monitor peak). If not possible and taken 6-14hr after the last and then use the nomogram to interpret. If patients are >65 years old, have abnormal renal function or poor urine output then you need to check levels before giving. If patients are normal then give dose before levels coming back. Check dosing twice weekly for normal patients, before every dose for abnormal renal function. Needs micro advice if given for >7 days.
VANC- trough levels- 1hr before dose (11hr post dose usually as you give it every 12hr). Usually they are around 10-15mg/L. First dose is taken after 3rd or 4th dose. Give before the results come back. Monitor every 2-3 days.
TEICO- 3-5 loading doses then reduce from BD to OD but you don’t have to wait for results to come back you just give. Trough levels are taken when the loading dose is complete (day 3,4, 5- depending on how many doses are given) and are only required if you plan to give treatment for >7 days.
what drug to give for diarrhoea non infectious
loperamide 2mg orally up to 3hrly or coedien 30mg oral up to 6hrly
insomnia
zopiclone max 3-7 days 7.5mg adults and 3.75mg in elderly
hospital initiated only= For people over 55 years of age with persistent insomnia, treatment with a prolonged-release melatonin may be considered.
The recommended duration of treatment is a maximum of 13 weeks.
Non-pharmacological CBTi, sleepio app, sleep diary.
cramping vs secretion
hyoscine Butylbromide for Bowels/Buscopan
Hyoscine Hydrobromide for Hydro- water drowning in secretions
brain vessel vasospasm drug
nimo
nimodipine
statins after stroke
yes for ischameeic regardless of level of cholesterol
no for haemorrhagic
can start as soon as safe swallow in ischaemic
stockings and LMWH post stroke ?
no!- intermattic penumatic compression if they’re going to be immobile.
blood pressure management after stroke?
Only if low low risk patinets, i..e, none of your a-e patients (if GCS<6, they’re about to go for surgery/haematoma evacuation, or who have an underlying structural cause, or who have a very large haematoma with a poor expected prognosis. DONT)
What antiemetic is contraindicated in long term palliative care and why
ondansetron - constipation causing
domperidone parkinsons?
allowed used in substitute for metaclopramide in partial bowel obstruciton, migraines, Nausea where vomitting does help (nausea that impairs gastric motility)
When prescribing a new drug on a chart of a patient that’s already been in 5 days, what do you need to make sure you do?
cross off the first 5 days so people dont get confused and give duplicates due to it being recorded on the wrong day (see morphine sulfate)
what can you write in PRN section ‘max dose’ for oramorph?
either their total daily dose of morphine or write when taking ≥2 daily breakthroughs. (NICE)
prescribe paracetamol for a 10 year old child
NOTE, SOME CONCENTRATIONS ARE NOT ALLOWED IN CERTAIN AGES I.E., 500mg/5mL under 12 or 16?
prescribe codeine for pain for a 10 year old child
first of all, you should find out that it is CONTRAINDICATED <12 YEARS.
Second of all you should make sure it is only being given for 3 DAYS MAXIMUM
But we have done this prescription assuming it is a 12 year old child so you can see how it would be prescribed.
Give me an exmaple of how to prescribe max dosing for an opioid
either 6 doses (as breakthrough is 1/6 total) or after 2 doses seek doctor review (as if theyre using that much it is an indication to go up)
whats wrong with each of these and correct them
Why would you change to morphine?
why is this answer wrong?
the 24ml is not specific to the concentration
it is the FINAL volume so you need to minus 3mL from it!
Where to find insulin on BNF?
- Type in the name i.e., insulin lispro, insulin detemir. scroll all the way to the bottom it will have ‘other drugs in this section that are ‘rapid acting’ or ‘long acting’. this will tell you whether they are prescribed correctly if you are looking at it in terms of drug review
Dalteparin/LMWH need to knowss….. When do you measure Xa levels? What time? Do you remove the bubble before injecting? Do you rub the site after injecting?
take them on day 3 (3-4 hours after dosing) in <50kg or >90kg, recurrent DVT, renal impairment.
No you dont remove the bubble, this helps propel it into the subcut (unlike IV where you dont want it to get into the circulation). No you dont rub the site, this increases risk of bruising.
When changing from LMWH to warfarin how do you do this?
LMWH and warfarin given concurrently until INR ≥2 and then remove LMWH (usually for 5 days), whereas when you come off warfarin –> LMWH you have to wait 2 days before adding LMWH in.
If it is pre op, 24hr before you also have to make sure that INR is <1.5.
when changing LWMH to DOAC how is this done?
DOAC given at the same time that LMWH will be given
is UFH or LMWH preferred in renal impairment and does it depend on situation and if so why, give me examples of where 1 would be used over the other BNF CKS guidelines
ufh - cleared by liver
lmwh - cleared by kidneys. - not effective if crcl <30.
Benefits of UFH - short half life, reversible. Need to montior anti-Xa or APTT.
Benefits of LMWH - less frequent monitoring but do still need to check Xa.
ufh in hospital if <30, doac (speicifally apixban as dabigatran adn rivaroxiban have higher crcl cut offs!!) when discharged.
LMWH in hospital if not as bad renal impairment.
lithium order kinetics? When do you check dose?
linear - double dose you double concentration as it is not metabolised or changed in the body. check it at least 6hr post dose.
how do you prescribe creams?
on dose - put 1 application
