Prescribing Safety Flashcards
What information is important to include on the drug chart if a drug is being used ‘as required’? (2)
- The maximum dose or the maximum frequency
2. The indication
What information is important to include on the drug chart if an antibiotic is prescribed? (2)
- The indication
2. The stop/review date
When is it important to include duration on the drug chart?
If the drug is not long term e.g. antibiotic
If the drug is prescribed in the GP setting
The general rule is don’t use the trade name of drugs, however which drug is an exception to the rule?
Tacrolimus - it is important to use the brand name because switching between brands can cause toxicity
What are the enzyme inducer drugs (use the pneumonic)?
PC BRAS
P - Penytoin C - Carbamezapine B - Barbiturates R - Rifampicin A - Alcohol (chronic excess) S - Sulphonylureas
Whats are the enzyme inhibitor drugs? (use the pneumonic)
AO DEVICES
A - Allopurinol O - Omeprazole D - Disulfiram E - Erythromycin V - Valporate I - Isoniazid C - Ciprofloxacin E - Ethanol (acute intoxication) S - Sulphonamides
What is an example of an enzyme inibitor interaction?
Warfarin and Erythromycin
Erythromycin as an enzyme inhibitor can increase the drug concentration of Warfarin therefore causing the INR to dangerously increase, if the Warfarin is not reduced
Why are patients on long-term steroids unable to mount an adequate sick response?
They have adrenal atrophy
What should a patient on long-term steroids receive before surgery and why?
IV steroids at induction of anaesthesia
This is because they are unable to mount the stress response therefore would have profound hypotension otherwise
It is similar to patients taking double the dose of their steroids on sick days
Which drugs should be stopped before surgery? ( used the pneumonic)
I LACK OP
I - Insulin L - Lithium A - Anticoagulants/antiplatelets C - COCP/HRT K - K-sparing drugs
O - Oral hypoglycaemics
P - Perindopril and other ACE-inhibitors
When do you stop the COCP/HRT before surgery?
4 weeks before surgery
When do you stop Lithium before surgery?
Day before surgery
When do you stop potassium-sparing diuretics before surgery?
Day of surgery
When do you stop ACE inhibitors before surgery?
Day of surgery
When do you stop anticoagulants (inc prophylaxis dose) and antiplatelets?
Variable between hospitals and operations (some are even continued through the operation)
When should Oral hypoglycaemics be stopped before surgery?
Variable between hospitals and operations
Why should Oral hypoglycaemics be stopped before surgery? What should be done instead
Patients are nil by mouth before surgery therefore should not take metformin as it may cause lactic acidosis
A sliding scale should be used instead with hourly blood glucose monitoring and adjusting as appropriate (tighter control)
What is the pneumonic to help with prescribing?
PReSCRIBER
What does PReSCRIBER stand for?
P - Patient details Re - Reaction (i.e. allergy plus the reaction) S - Sign the front of the chart C - Contraindications R - Route for each drug I - Intravenous fluids if needed B - Blood clot prophylaxis if needed E - antiEmetics if needed R - pain Relief if needed
How many pieces of patient identifying info needs to be on a drug chart and give examples of suitable ones?
3 are needed:
Patient name
DOB
Hospital number
Which two drugs contain penicillin, in a way which is not obvious?
Co-amoxiclav - amoxicillin and clavulanic acid
Tazocin - pipercillin and tazobactam
What are the 4 main groups of drugs, that i must know the contraindications for?
- Drugs that increase bleeding (anticoagulants, antiplatelets)
- Steroids
- NSAIDs/Aspirin
- Anti- hypertensives
In which patients are antiplatlets/anticoagulants contraindicated?
Bleeding
Suspected bleeding
At risk of bleeding
Give an example of why a patient might be at risk of bleeding
Prolonged prothrombin time due to liver disease
What pneumonic can be used for the side effects of steroids?
STEROIDS
What does the STEROIDS pnuemonic stand for?
S - Stomach ulcers T - Thin skin E - oEdema R - Right and Left heart failure O - Osteoporosis I - Infection (inc Candida) D - Diabetes (commonly causes hyperglycaemia and uncommonly progresses to diabetes) S - cushing's Syndrome
What is the ‘safety considerations’ pneumonic for NSAIDs?
NSAID
What does the NSAID pneumonic stand for?
N - No urine (i.e. renal failure) S - Systolic dysfunction (i.e. heart failure) A - Asthma I - Indigestion (any cause) D - Dyscrasia (clotting abnormality)
Why is Aspirin not subject to the same level of caution as NSAIDs used for pain management?
Because although it is an NSAID, it is not used at relatively low doses for the management of cardiovascular and cerebrovascular disease which is not necessary for those extra precautions
What are the 3 anti-hypertensive side effect categories you should always classify in?
- Hypotension
- Mechanism: Bradycardia or Electrolyte disturbance
- Individual drug
Which anti-HTNs can cause hypotension?
All of them
What is the earliest symptom of hypotension?
Postural hypotension
Which antihypertensives cause bradycardia?
Beta blockers (and some calcium channel blockers)
Which CCBs have a bradycardia effect and why?
The non-dihydropyridines - because they have inhibitory effects on the SAN and AVN
What are the non-dihydropyridines useful for treating?
Hypertension, reduces oxygen demand, and helps to control the rate in tachyarrhythmias
Give drug examples of non-dihyrdropyridine (2)
Diltiazem
Verapamil
What is the effect of the dihydropyridine CCBs?
Peripheral vasodilators + have very little effect on the myocardium
What are the dihydropyridine CCBs used for? (3)
- Hypertension
2. Post-intracranial haemorrhage associated vasospasm 3. Migraines
Which anti-HTNs cause electrolyte disturbance?
- ACE- inhibitors
2. Diuretics
4 individual anti-HTN drugs have their own side effects - name the 4 drugs
- ACE inhibitors
- Beta blockers
- CCBs
- Diuretics
Give an example of dihydropyridine drugs (3)
- Amlodipine
- Nifedipine
- Nicardapine
These end in -pine
What is the individual side effect of ACE-Inhibtors?
Dry cough
What are the individual side effects of Beta blockers? (2)
Wheeze in asthmatics
Worsening of acute heart failure (but help in chronic heart failure)
What is the individual side effect of CCBs? (2)
Peripheral oedema and flushing
What is the individual side effect of Diuretics? (3)
- Renal failure
- Thiazide diuretics can cause gout
- Potassium-sparing diuretics can cause gynaecomastia
Name an example of a thiazide diuretic
Bendroflumethiazide
Name an example of a potssium-sparing diuretic
Spironolactone
If a patient is Nil by mouth, can they still recieve their oral medication before surgery?
Yes they can and should
If a patient is vomiting a lot how should you give the antiemetic?
non oral: i.e. IV, IM, SC
NOTE: cyclizine and metoclopramide doses dont change regardless of the route
IV fluid replacement - you always give 0.9% saline except in which 4 cases?
- Hypernatraemic
- Hypoglycaemic
- Ascites
- Shocked from bleeding
What replacement fluid do you give if someone is hypernatraemic?
5% dextrose
What replacement fluid do you give if someone is hypoglycaemic?
5% dextrose
What replacement fluid do you give if someone has ascites? and why?
Human-albumin solution (HAS) - the albumin maintains oncotic pressure (the higher sodium content in 0.9% saline will worsen ascites)
What replacement fluid do you give if someone is shocked from bleeding?
Blood transfusion (but give crystalloid first if no blood is available)
If someone is tachycardic or hypotensive how much /how fast do you give replacement fluids? (what about if they have heart failure?)
500ml bolus immediately
if HF then 250ml bolus immediately
How much/how fast do you give replacement fluid if they are only oliguric (and it is not due to urinary tract obstruction?)
1L over 2-4 hours
In the following scenarios state roughly how fluid depleted each individual is:
- reduced urine output (<30ml/h)
- reduced urine output + tachycardia
- reduced urine output + tachycardia + shocked
- 500ml depleted
- 1L depleted
- > 2L fluid depleted
What is the max rate of infusion for IV potassium?
10 mmol/hr
How much maintenance fluids do adults vs elderly require as a general rule?
adults 3L IV fluids/ 24 hours
elderly 2L IV fluids/24 hours
What bags of fluid would you usually give for maintenance?
1 salty 2 sweet
(remember sweet tooth)
1 L of 0.9% saline
2 L of 5% dextrose
With a normal potassium level, how much potassium is needed per day in the maintenance fluids and how do you administer this?
adults need 40 mmol of K+ per day
Put 20 mmol KCl in 2 of the maintenance fluids bags
How fast do you give maintenance fluids in adults vs elderly?
adults 3L /24 hours - therefore 8 hourly
elderly 2L/12 hours - therefore 12 hourly
What do most pts coming into hospital receive for VTE prophylaxis? (2)
LMWH e.g. dalteparin 5000 units daily SC
and compression stockings
Which pts should not be prescribed compression stockings?
Those with peripheral arterial disease (indicated by abscent foot pulses)
What might happen if a patient with peripheral arterial disease is prescribed compression stockings?
Acute limb ischaemia
In which patients (2) should the antiemetic metoclopramide be avoided? why?
- Parkinson’s disease as it is a dopamine antagonst so can exacerbate symptoms
- Young women - due to risk of dyskinesia (esp acute dystonia)
Which antiemetics can you give if a patient is nauseated? (3) - include the dose and route
Cyclizine 50 mg 8 hourly IM/IV/oral
Metoclopramide 10mg 8 hourly IM/IV (if HF)
Ondansetron 4mg or 8mg 8 hourly IV/oral
When should Cyclizine be avoided and why?
In HF as it causes fluid retention
Which antiemetics can you give if a patient is NOT nauseated?
Cyclizine 50 mg UP TO 8 hourly (IV/IM/oral)
Metoclopramide 10mg UP TO 8 hourly (IM/IV) if HF
these are given PRN if not nauseated
Which analgesic do you give regularly if there is no pain?
NONE! if there is no pain, it shouldnt be regular, but PRn
Which analgesic do you give as required if there is no pain?
Paracetamol 1g up to 6 hourly oral
Which analgesic do you give regularly if there is mild pain?
Paracetamol 1g 6 hourly oral
Which analgesic do you give as required if there is mild pain?
Codeine 30 mg up to 6 hourly oral
Which analgesic do you give regularly if there is severe pain?
Co-codamol 30/500, 2 tablets 6 hourly oral
Which analgesic do you give as required if there is severe pain?
Morphine sulfate (10mg/5mL) 10 mg up to 6 hourly oral
Draw the table of analgesic choices
(see page 10 of PSA book)
How does oramorph come?
A a liquid
When are NSAIDs used in the analgesic choices?
At any stage they can be introduced regularly or PRN if not contraindicated
What is the first line analgesic for neuropathic pain?
Amitriptyline 10 mg oral nightly or pregabalin 75 mg oral 12 hourly
What is the maximum dose of paracetamol in patients >50kg vs <50kg?
> 50kg - max is 4g in 24 hours (this is 1g 6 hourly)
<50kg -max is 2g in 24 hours (this is 500mg 6 hourly)
What is a common mistake leading to overprescribing paracetamol?
Giving co-codamol and paracetamol
What are the 3 causes of a microcytic anaemia?
- Iron deficiency
- Thalassaemia
- Sideroblastic anaemia
What are the 4 causes of normocytic anaemia?
- Anaemia of chronic disease
- Acute blood loss
- Haemolytic anaemia
- Renal failure (chronic)
What are the 6 causes of megaloblastic anaemia
- B12 deficiency
- Folate deficiency
- Liver disease
- Excess alcohol
- Hypothyroidism
- Hamatological diseases beginning with M -myeloproliferative, myelodysplastic, multiple myeloma
Which type of anaemia is pernicious anaemia and why?
Macrocytic - becasue in pernicious anaemia there if a deficency of B12
What are the three causes of neutrophilia (high neutrohils)?
- Bacterial infection
- Tissue damage (inflammation, infarct, malifgnancy)
- Steroids
What are the 4 causes of neutropenia (low neutrophils)?
- Viral infection
- Clozapine (antipsychotic)
- Carbimazole (antithyroid)
- Chemotherapy or radiotherapy
Thrombocytopaenia can can be caused by reduced production or increased destruction - what are the 3 causes of reduced production?
- infection (viral)
- drugs e.g. penicillamine
- myelodysplasia, myelofibrosis, myeloma
Thrombocytopaenia can can be caused by reduced production or increased destruction - what are the 5 causes of increased destruction?
- Heparin
- Hypersplenism
- DIC (disseminated intravascular coagulation)
- Idiopathic Thrombocytopaenic purpura
- HUS (haemolytic uraemic syndrome)/TTP (thromboric thrombocytopaenic purpura)
What are the reactive causes of thrombocytosis (high platelets)? (3)
- Bleeding
- Tissue damage (infection/inflammation/malignancy)
- Post-splenectomy
What is the primary cause of thrombocytosis (high platelets)?
Myeloproliferative disorders
What types of hyponatraemia can hypothyroidism cause?
Euvalaemic and Hypervolaemic
Which drugs tend to cause SIADH?
Carbamezapine and antipsychotics
Hypernatraemia causes all begin with D - what are they? (4)
- Dehydration
- Drips (too much IV saline)
- Drugs
- Diabetes insipidus
What are the pneumonics for Hypokalaemia and Hyperkalaemia and what is a good way to remember which pneumonic goes with which?
Hypokalaemia: DIRE
Hyperkalaemia: DREAD
(I dread TOO MUCH work)
List the causes of Hypokalaemia
D - drugs (loop and thiazide diuretics)
I - inadequate intake or intestinal loss (diarrhoea/vomiting)
R - renal tubular acidosis
E - endocrine (Cushing’s and Conn’s syndromes)
List the causes of Hyperkalaemia
D - Drugs (potassium sparing diuretics and ACE-inhibitors)
R - Renal failure
E - Endocrine (Addisons’s disease)
A - Artefact (very common due to clotted sample)
D - DKA (but when insulin is given the K+ drops)
What two things can a raised urea indicate?
Kidney injury OR an upper GI bleed
Why does urea increase in an upper GI bleed?
Because it is a breakdown product of amino acids e.g. globin chains in haemoglobin)
Or the haemoglobin in the blood can be broken down by gastric acid and then the urea absorbed into the bloodstream (this is what happens if someone has a bloody steak)
If a patient has a raised urea and is not dehydrated what should this prompt you to look at and why?
Their haemoglobin because if it has dropped the patient has probably had an upper GI bleed
What are the pre-renal causes of acute kidney injury? (4)
- dehydration
- sepsis
- blood loss
- renal artery stenosis
What are the intrinsic causes of acute kidney injury?
INTRINSIC Ischaemia (due to pre-renal AKI causing acute tubular necrosis) N - nephrotoxic antibiotics Tablets (ACEi , NSAIDs) Radiological contrast Injury (rhabdomyolysis) Negatively birefringent crystals (gout) Syndromes (glomerulonephritidies) Inflammation (vasculitis) Cholesterol emboli
What are the nephrotoxic antibiotics?
Gentamycin
Vancomycin
Tetracyclines
Sometimes in severe pre-renal AKI, creatinine can also rise - if this happens how can you differntiate from non pre-renal causes?
urea x 10 - if it exceeds the creatinine then it means a relatively greater increase in urea compared to creatinine which suggests pre-renal aetiology
What are the 4 markers of hepatocyte injury or cholestasis?
- Bilirubin
- ALT
- AST
- ALP
What are the markers of synthetic function? (2)
Albumin
Vitamin K-dependent clotting factors
Which 2 investigations give an idea of the vitamin K-dependent clotting factors?
Prothrombin time
INR
How do you divide up the causes of post-renal causes of AKI?
In lumen
In wall
External pressure
What are the in lumen causes of a post-renal AKI? (2)
- Stone
2. Sloughed papilla
What are the In wall causes of a post renal AKI? (2)
- Tumours:
Renal cell carcinoma
Transitonal cell carcinoma - Fibrosis
What are the External pressure causes of a post renal AKI? (4)
BPH
Prostate cancer
Lymphadenopathy
Aneurysm
What is the pattern of LFT derrangement in pre-hepatic jaundice?
Raised bilirubin on its own
What is the pattern of LFT derrangement in intrahepatic jaundice?
Raised bilirubin
raised ALT/AST