Facts to know! Flashcards
prescribing prednisolone for COPD exacerbation
going to seem like a strangely large number of drugs
e.g. if you prescribe 30mg of prednisolone, because the tablets come in specific mg such as 5mg, the patient will take 6 tablets to make up 30mg
Guidance: 30mg PO daily for 5 days
24 hours ago a 56 year old man had a stroke. After he is deemed to have an unsafe swallow and therefore he is commenced on IV fluids to prevent dehyration.
See the fluids that he has received in the last 24h
Write a prescription for one IV fluid that is most appropriate as the enxt bag to maintain his hydration while he remains nil by mouth
glucose 5%/potassium chloride 0.3% solution
potassium chloride and glucose IV infusion is the best choice.
- he has already received 2l of sodium chloride 0.9% in the last 24h -> this will provide water, but risk sodium and chloride overload
- in 0.9% NaCL there is 154 mmol Na and Cl in each bag and for an 80kh man the daily requirement is 80mmol each so yesterday he had x4 the amount required
- he also requires some potassium as he only had 40 mmol yesterday and requires 80mmol per day
- his blood glucos eis in normal range, so it is reasonable to maintain hydration using 5% glucose
Infusion rate
- the ideal infusion rate is 1L over 8-12 h using a bag contain 0.3% potassium (40 mmol/l)
0.15% potassium in mmol
20mmol
0.3% potassium in mmol
40 mmol
a 55 year old present to the GP for review of her HRT_ she requests a new preparation that will not give her monthly withdrawal bleeds like her current medication- she would like to keep a transdermal patch system going
DH
* Estrodiol 50micrograms/24h transdermal patch
* Estradiol 50 micrograms/ norethisterone acetate 170 micrograms 24h transdermal patch comb one patch transdermally twice weekly for 2 year
Write a prescription for one drug that will prevent withdrawal bleeding
if she is having withdrawal bleeds we can deduce she has a uterus
- women with a uterus should have a product containing both oestrogen and progesterone
- this protects against endometrial cancer from unopposed oestrogen
Preventing withdrawal bleed
- to prevent withdrawal bleed the product needs to release the same dose continuously, rather than a sequential product
- she would like a transdermal patch
simply to prevent withdrawal bleed when using HRT
need a product that releases the same dose continuously, rather than a sequental product
which drug not good for peripheral vascular disease
beta blockers such as atenolol -> cause peripheral vasoconstriciton and can worsen ischaemia in PVD
common drugs which cause hyperkalaemia
ACEi
ARBs
Potassium sparing diuretics and aldosterone antagonists e.g. spironolactone
Heparins
Tacrolimus
Ciclosporin
Eplerenone
Adjusting insulin
48 year old attends clinic. She does not report any hypoglycaemic symptoms or episodes, bit has noticed some polyuria in the evenings.
PMH: T1DM
DH:
- Lisinopril 10mg PO daily
- Atorvastatin 20mg PO daily
- Biphasic insulin aspart (NovoMix30) 44 units SC at breakfast and 32 units SC with evening meals
Her blood glucose at preprandial and bedtime:
What is the most approrpiate management to improve glycaemic control
dont change the type of insulin -> just increase morning dose of insulin up a few units (10%)
which antibiotics can interfere with warfarin and contraceptives
P450 inhibitors- increase warfarin conc in blood, increasing INR
- macrolides such as Clarithromycin
- Metroidazole
- Ciprofloxain
- Isoniazid
P450 inducers
- Rifampicin
Drugs which cause hypokalaemia
Thiazide diuretics e.g. indapamide
Loop diuretics e.g. Furosemid
Theophylline
Insulin
Mannitol
Which fluids to give a hypoglycaemic patient <4mmol/l who is unconscious
glucose 20% 100mL IV STAT (over 15 mins)
62 year old presents to GP with aching muscles. Recently started on Atorvastatin 80mg.
Creatine kinase of 1500 U/L (24-195).
What si the most appropriate decision to make regarding the atorvastatin prescription
-when statin is suspected to be the cause of myopathy and the CK concentration is markedly elevated (>5 x upper limit of normal), or if musuclar symptoms are severe, treatment should be discontinued
- if symptoms resolve, and CK levels return to normal, the statin should be reintroduced at a lower dose
- if this does not work then can switch to a new statin e.g. Rosuvastatin
Oral morphine conversion to fentanyl patch
add up all of the current oral morphine being taken
ad then use conversion on BNF to calculate the equivalent for fentanyl patch
contunue levothyroxine sodium 100 micrograms PO daily
classic dose for pulmonary oedema whichr equires immediate treatment e.g. low sats and breathlessness
furosemide 10mg/ml injection - 50mg IV daily
thromboprophylaxis for elective hip replacement
should either be given:
- LMWH for 10 days, followed by low-dose aspirin for a furter 28 days
- or LMWH for 28 days in combo with anti-embolic stockings until discharge
- or rivaroxaban
e.g. Dalteparin sodium 25 000 units/ mL -> give 500 units subcut daily for 28 days
when should antiplatelet therapy be stopped before surgery
e.g. aspirin and clopidogrel
7 days
which drugs are nephrotoxic
- ACEi
- ARB
- NSAIDs
- Thiazides
- Allopurinol
- Aminoglycosides e.g. gentamycin, clarithromycin
drugs which can cause hyponatraemia
- Thiazide diuretic e.g. bendroflumethiazide
- Loop
- Spironolacton
- Heparin
- Antipsychotics
- Antiepileptics e.g. carbamazepine, sodium valproate
- Citalopram
- ACEi
- ARB
- Heprin
Answer: Trimethoprim 200 mg PO 12 hrly for 7 days
- although blocks folate metabolsim, and may exacerbate pre-existing folate deificency, this doe snot preclude its use for a short course of treatment
- 7 days indicated in males
Why not Nitro
Nitrofurantoin should be avoided if eGFR is less than 45mL/min/1.73m2
vitamin K also known as
Phytomenadione
BNF says INR >1.5 on the day before surgery
- give phyromenadione (Vit K) 1-5 mg PO
she should be aware that the efficacy of oral POPs is reduced when using topiramate (enzyme inducer) -> therefore alternative method of contraception until 4 weeks after ceasing taking topiramate
if patient starts and ACEi and has slightly riased creatinine what should you do
continue the ACEi daily and repeat UEs after 1 week
a small rise in creatinine (<20%) is to be expected when starting ACEi and does not require investigation or change in prescription
best way to monitor beneficial effect of furosemide
weight -> aim of 0.5kg decrease per day
monitoring for adverse effects when taking carbimazole
FBC -> looking for neutropenia
increase insulin e.g. biphasic isophane insulin (Humulin M3) to 22 units SC
- increase the usual dose of 10% would be appropriate way to manage a transient rise in BM caused by corticosteroids
Gentamicin monitoring
Patient prescribed gentamicin 7mg.kg IV. Her first dose is given at 1700h today. Shes weights 60kg
Investigations
- Serum gentamicin at 2100 is 8.micrograms/ml
What should you do?
Important: what would the concentration of: 1 litre bag of normal saline contains 1g of aminophylline.
1mg/ml
how long can it take for antidepressants to become effective
important that patients realise that they must take their medication regularly for up to 6 weeks before feeling a positive effect
some people feel worse and even more suicidal to start with
good trick question
fluids for hypernatraemia
IV
5% glucose
corrected at a rate of no greater than 0.5 mmol/hour
Causes: all begin with D
- dehyration
- drips (too much NaCl)
- diabetes insipidus
- drugs
paracetamol prescribing
1g every 4-6 hours up tp 4g a day
in patients <50kg the maximum dose is 500mg 6-hourly
IV potassium should not be given at a rate faster than
10mmol/hour
classic IV fluid prescription for a patient needing maintenance because they are nill by mouth
Adults tend to require 3 L IV fluid per 24 hours and elderly require 2 l
example regime: 1 salty 2 sweet
- 1L of 0.9% saline
- 2L of 5% dextrose
- Will require addition of KCL -> chrck UEs. If normal potassium levels give around 40 mmol KCL per day-> so put 20mmol KCL in 2 bags)
maintenance: how to give fluids
if giving 3l per day = 8 hourly bags (24/3)
if giving 2l per day= 12 hourly (24/2)
blood clot prophylaxis
- most patients admitted will be given dalteparin 5000 units daily subcut
- Compression stockings watch out for PAD
Antiemetic choices
- Cyclizine 50 mg 8 hourly for most cases a good choice for almost all cases except cardiac cases- can worsen fluid retention
- Ondansetron 4mg or 8mg 8-hourly
- Metoclopramide 20mg 8 hourly if Heart failure
key side effect of cyclizine
fluid retention
who should never be given metoclopramide
dopamine antagonist so will exagerate symptoms in Parkinsons patients
- should also not give haloperidol
first line maagement of neuropathic pain
amitripytilien or pregabalin
- duloxetine for painful diabetic neuropathy
management of high INR
asthma management
Smoking status and COCP
Her smoking status is important as being older than 35 years and smoking more than 15 cigs/day is an absolute contraindication to the COCP.
Drugs contraindicated in breast feeding:
LAMBAST + 3Cs
Lithium
Amiodarone
Methotrexate
Benzodiazepines
Aspirin
Sulfonylureas
Tetracyclines
Chloramphenicol, Carbimazole, Ciprofloxacin
which heart failure medications should not be used together
beta-blockers and verapamil
prescribing levothyroxine
look at the TSH
TSH <0.5 - decrease dose
TSH 0.5-5 - nil action same dose
TSH>5 -increase dose
the higher the PT, the higher the
INR
- warfarin inhibits synthesis of vitamin K dependent clotting factors (II,VII,IX,X) -> this prolongs PT from which INR is derived
if a patient on warfarin has a major bleed
- STOP warfarin
- give 5-10mg IV vitamin k
- give prothrobin complex
gentamicin is monitored due to risk of
Nephrotoxicity
Ototoxicity
using the gentamicin nomogram
plot the blood concentration on the Y-axis
- if the resultant point falls within the 24h area (q24h), then continue at the same dose
- if it falls above the 24h area, then change the dosing interval as follows:
- if it falls in the 36h, change to 36h dosing
- of it falls in the 48h area, then change to 48h dosing
- if it falls above the 48h area then repeat the gentimicin levela nd only re-dose when conc is <1mg/l
how to manage over anticoagulation
No bleeding
- 5-8: omit warfarin for 2 days then reduce dose
- >8: omit warfarin and give 1-5mg PO vitamin k
Minor bleeding
- 5-8: omit warfarin and give 1-5mg IV vitamin K
- >8: omit warfarin and give 1-5mg IV vitamin K
when should antihypertensives be given
prescribed as nightly
rate control management of AF if asthmatic and therefore cant take b blocker
Verapamil (superior to diltiazem- not actually licened for AF- can cause profound bradycardia in presence of beta blcokers)
Diltiazem
which drug will actually lower potassium (as opposed to protecting the heart)
rapid acting e.g. actrarapid Insulin
Inhibitors
The mnemonic SICKFACES.COM can be used to easily remember common CYP450 inhibitors.
- Sodium valproate
- Isoniazid
- Cimetidine
- Ketoconazole
- Fluconazole
- Alcohol & Grapefruit juice (alcohol)
- Chloramphenicol
- Erythromycin
- Sulfonamides
- Ciprofloxacin
- Omeprazole
- Metronidazole
inducers
The mnemonic CRAP GPs can be used to easily remember common CYP450 inducers.
- Carbemazepines
- Rifampicin
- Alcohol (alcohol)
- Phenytoin
- Griseofulvin
- Phenobarbitone
- Sulphonylureas
management of confirmed PE or DVT
Apixiban or Rivaroxaban
common painkiller which can cause urinary retention
morphine
risk of wernickes encephalopathy
diabetic medications and surgery
Antidepressants such as sertraline can cause
electrolye imbalance such as Hyponatraemia
- present as confusion, drowsiness, convulsions
depression management
anxiety management
missed lithium dose
lithium monitoring
BMI >26 so either give Ulipristal acetate or double dose of levongestrel
**
emergency contraception
if in doubt use ulipristal acetate
carbamezapine is an inducer! reduces effect of POP and COCP
