Pharmacology Flashcards
What are the properties of the main three DOACs?
- Mechanism
- Excretion
- Indications
Apixaban
- Factor Xa inhibitor
- Faecal excretion
Rivaroxaban
- Factor Xa inhibitor
- Liver excretion
Dabigatran
- Thrombin inhibitor
- Renal excretion
All are indicated for:
- Prevention of VTE following hip/knee surgery
- Treatment of DVT and PE
- Prevention of stroke in non-valvular AF*
All are taken orally
What info do you need to include on a PRN medication ?
Indication and maximum frequency (max dose or BD etc.)
Mnemonic for enzyme (p450) inducers?
PC BRAS
Phenytoin
Carbamazepine
Barbiturates
Rifampicin
Alcohol (chronic)
Sulphonylureas
Mnemonic for enzyme inhibitors?
AO DEVICES
Allopurinol
Omeprazole
Disulfiram
Erythromycin
Valproate
Isoniazid
Ciprofloxacin
Ethanol
Sulphonamides
What should you do with prescribing long-term drugs if patient is having surgery?
Some need to be stopped (I LACK OP)
Most should be continued
Steroids need to be increased (and given IV)
What drugs need to be stopped before surgery?
I LACK OP
Insulin
Lithium - day before
Anticoag/platelets
COCP/HRT - 4 weeks before
K+ sparing diuretics - Day of
Oral hypoglycaemics
Perindopril (and other ACEI) - Day of
Mnemonic to use when looking for prescription errors?
PReSCRIBER
Patient details
Reaction
Sign the front of the chart
Contraindications for each drug check
Route of each drug check
IV fluid if needed
Blood clot prohylaxis if needed
ant-Emetic if needed
Relief from pain - prescribe if necessary
4 main groups of drugs that can be contraindicated?
- Drugs that increase bleeding risk should not be given to a bleeding patient, a suspected bleeding patient, or one at risk.
- Steroids (if showing S/Es) (STEROIDS)
- Stomach ulcers
- Thin skin
- Edema
- Right and left HF
- Osteoporosis
- Infection
- Diabetes
- Syndrome of Cushings - NSAIDS for NSAIDS
No urine -
Systolic dysfunction (HF)
Asthma
Indigestion
Dyscrasia (clotting disorder)
- (Aspirin only in Indigestion and clotting).
- Antihypertensives have three categories
- Hypotension
- Mechanisms
a. Electrolyte disturbance with ACEI
b. Bradycardia with B-blockers - Specific S/Es
- ACEI - dry cough
- BBlockers - wheeze in asthmatics
- Calcium channel blockers - peripheral oedema and flushing
- Diuretics - renal failure
When is erythromycin most commonly contraindicated?
Concomitant prescription with warfarin (Enzyme inhibitor)
When is prophylactic heparin commonly contraindicated?
Acute ischaemic stroke
Steroid S/Es mnemonic?
(STEROIDS)
- Stomach ulcers
- Thin skin
- Edema
- Right and left HF
- Osteoporosis
- Infection
- Diabetes
- Syndrome of Cushings
NSAIDS contraindication mnemonic?
NSAID
No urine -
Systolic dysfunction (HF)
Asthma
Indigestion
Disordered clotting
In what two situations do you prescribe fluids?
Replacement fluids
Maintenance fluids
Which fluids should you use in replacement?
0.9% saline in ALL unless:
- Pt is hypernatraemic or hypoglycaemic: 5% dextrose
- Has Ascites: Human-Albumin Solution (HAS)
- Is shocked, with systolic BP <90mmHg: give gelofusin (apparently)
- Is shocked after bleeding (give blood).
How much fluid should you give when giving as replacement?
If tachycardic/hypotensive then give 500ml bolus (250 in HF)
If only oliguric then give 1L over 2-4 hours then reassess (HR, BP and urine O/P) then change according to their response.
As a general rule don’t prescribe >2L of fluid for a sick patient
What fluids should you give and how much (vol) should you give in maintenance therapy?
General rule: Adults 3L over 24 hours, Elderly 2L.
1 salty 2 sweet: 1L 0.9% saline followed by 2L 5% Dextrose.
Potassium should be guided by U&Es. If normal then:
- 40mmol KCL (20mmol in two bags).
- NO MORE THAN 10mmol AN HOUR)
How fast should you give maintenance fluids?
3L a day = 8hrly bags (24hrs/3)
2L a day = 12 Hrly bags (24hrs/3)
In RL must:
- Check U&Es
- Check fluid status (JVP, oedema)
- Check pts bladder is not palpable (obstruction)
When are compression stockings contraindicated?
Patient with peripheral arterial disease (PAD)
What antiemetic should you prescribe, and when?
Cyclizine in most cases (50mg) any route, apart from heart failure (worsens fluid retention)
In Heart Failure metoclopramide 10mg, however is dopamine antagonist so not in:
- Parkinson’s disease
- Young women (dyskinesia)
Pain control prescribing guidance/rules?
No pain
- PRN Paracetamol 1g up to 6hrly, oral
Mild Pain
- Paracetamol 1g 6hrly, oral
- PRN Codeine 30mg, up to 6-hrly oral
Severe pain
- co-codamol 30/500 2 tablets 6 hrly oral
- PRN morphine sulphate 10mg up to 6-hrly oral
Can introduce ibuprofen (400mg 8-hrly) if not contraindicated
Neuropathic pain is different (amitriptyline or pregabalin)
Electrolyte disturbance caused by thiazide diuretics (e.g. bendroflumethiazide)
Hypokalaemia
What main class of medications should be stopped in constipation?
Opiates - constipation.
What diuretics might cause both hypokalaemia and hyponatraemia?
All diuretics can cause hyponatraemia
Loop and thiazide diuretics can also cause hypokalaemia
Pt is on Furosemide, paracetamol, aspirin, enalapril, amlodipine and enoxaparin, pt has peripheral oedema (not caused by HF) what is the most likely culprit?
Amlodipine - Peripheral oedema is S/E of Ca++ channel blockers
What two commonly prescribed drug classes can exacerbate asthma?
NSAIDS, B-Blockers
What calcium channel antagonist can’t be used with beta blockers?
Verapamil
What route do you give insulin? When is this not so?
Given Subcut, apart from in sliding scales where is is IV - rapid acting
If a patient has asthma (but is asymptomatic) and is on ibuprofen, does it need to be stopped?
No it doesn’t - probably not NSAID-sensitive.
However with symptoms i.e. wheeze, then should be stopped.
General causes of anaemia as per their MCV?
Microcytic
- Iron deficiency anaemia
Normocytic anaemia
- Anaemia of chronic disease
- Acute blood loss
Macrocytic anaemia
- B12/Folate deficiency
- Excess alcohol intake/Liver disease
How to remember causes of hypernatraemia?
Begins with d Hyper-big d?
Dehydration
Drips (too much IV saline)
Drugs (with high sodium content)
Diabetes insipidus
Common causes of high neutrophils, low neutrophils and high lymphocytes (separately)?
High neutrophils
- Bacterial infection
- (tissue damage/steroids)
Low Neutrophils
- Viral infection
- Clozapine
- Carbimazole
High lymphocytes
- Viral infection
- (Lymphoma/CLL)
Common causes of low platelets (thrombocytopenia)
Reduced production
- Viral infection
- DRUGS (penicillamine)
Increased destruction
- Heparin
- Hypersplenism
- (DIC/ITP)
Common causes of high platelets (thrombocytosis)?
Reactive:
- Tissue damage (Infection/inflammation)
- Bleeding
Primary
- Myeloproliferative disorders
How do you remember the causes of SIADH?
SIADH
- Small cell lung cancer
- Infection
- Abscess
- Drugs (carbamazepine)
- Head injury
Causes of hyponatraemia? (just the important/common ones)
Hypovolaemia
- Fluid loss (vomiting/diarrhoea)
- Diuretics
Euvolaemic
- SIADH
Hypervolaemia
- Heart, Renal and Liver failure
How do you remember causes of hypokalaemia?
DIRE
Drugs (loop and thiazide diuretics)
Inadequate intake/Intestinal losses
Renal tubular acidosis
Endocrine
How do you remember causes of hyperkalaemia?
DREAD
Drugs (K+ sparing diuretics and ACEI)
Renal failure
Endocrine (addisons)
Artefact due to clotted sample
DKA
What are the three different types (causes) of AKI, their respective biochemical disturbance and their causes?
Prerenal (70%)
- Urea will be higher than creatinine
- Dehydration
- Shock
- Renal artery stenosis
Intrarenal (intrinsic) (10%)
- Creatinine rise much higher than urea
- Most importantly: Nephrotixic abx, DAMN drugs
Postrenal
- Urea rise is smaller than creatinine rise
- Something in the Urinary tract, stone, tumour, fibrosis, BPH/prostatic cancer.
How do you remember the other causes of an ALP rise?
ALKPHOS
Any fracture
Liver damage
K for kancer
Pagets disease of bone
Hyperparathyroidism
Osteomalacia
Surgery
What is the trick to changing the dose of Levothyroxine following TFTs?
Use TSH as a guide - aim for 0.5-5
If <0.5 then need to decrease (Hi TSH - too much thyroid, need to reduce)
If above then need to increase (Still hypothyroid).
Change by smallest amount offered
LFT results in prehepatic jaundice?
Isolated raise in Bilirubin (Haemolysis, Gilberts)
LFT results in intrahepatic jaundice?
Bilirubin rise in addition to ALP/ALT
LFT results in post-hepatic jaundice?
Raised bilirubin and ALP (Not ALT/AST).
ABG interpretation routine (PSA)?
- Check FiO2 (%)
- If on O2 and not sure about PaO2, subtract 10 from FiO2 and if PaO2 is lower then the pt is hypoxic. - Check PaO2 and PaCO2
- T1RF (Low pO2 and low/normal CO2) - Heart/Lung damage
- T2RF (Low pO2 and high CO2) - COPD, neuromuscular failure, chest wall deformity - Acid/base
- Look at pH, then PCO2 and HCO3
- Only CO2 abnormal = resp cause
- Only HCO3 abnormal = metabolic cause
- If both high or both low then there is compensation (if pH is not normal only partially compensated)
- if they are both abnormal but in opposite directions then there is both metabolic disorder and respiratory disorder, - Think about cause
Resp alkalosis - rapid breathing
Resp acidosis - COPD, neuromuscular failure, chest wall deformity
Metabolic alkalosis - Vomiting, diuretics, conns syndrome
Metabolic acidosis - DKA, Renal failure, ethanol/methanol
What are the DAMNN drugs that can cause AKI?
Diuretics
ACEI
Metformin
Nitrofurantoin/trimethoprim
NSAIDS
What are the cholinergic S/Es?
SLUD
Salivation
Lacrimation
Urination
Diarrhoea
(also midriasis, fasciculation, Hypotension and bradycardia)
Apart from the William Marrow technique what else will you see in Bundle branch block?
Wide QRS = >3 small squares, if they are wide check for BBB
Most common drugs that require monitoring?
Digoxin
Theophylline
Lithium
Phenytoin
Abx - Gent, vancomycin
Warfarin (obvs)
If the serum drug level is high, but the patient has serum level what should you do?
Still decrease the drug dose, apart from gent
If there are signs of toxicity, omit the drug for several days
What symptoms do you get in Digoxin Toxicity?
Confusion, Nausea, Visual halos, arrhythmias
What symptoms do you get in lithium toxicity?
Early: tremor
Mid: Lethargy
Late: arrhythmias, seizures, coma, renal failure
Phenytoin toxicity symptoms?
Gum hypertrophy, ataxia, nystagmus, peripheral neuropathy and teratogenicity.
Gentamicin toxicity symptoms?
Ototoxicity and nephrotoxicity
Vancomycin toxicity symptoms?
Ototoxicity and nephrotoxicity
Treatment if there is a major bleed whilst on warfarin?
Stop warfarin
Give 5-10mg IV Vitamin K
Give prothrombin complex
(if minor bleed give IV Vit k 1-3mg)
What is the treatment for over-anticoagulation whilst on warfarin (depending on the INR)?
<6 reduce warfarin dose
6-8 omit warfarin for 2 days then reduce the dose
>8 omit warfarin and give 1-5mg oral Vit K
When do you need bloods to monitor renal function in a patient who has just started ramipril?
1-2 weeks after starting
1% equals what in terms of mg to ml?
1g in 100ml
What medication do you give first in stable angina?
GTN
In pregnancy what is the best anti-epileptic medication to give?
Lamotrigine
If underweight or high creatinine then what medication should you avoid with diabetes?
Avoid metformin, give sulphonylurea
If a phenytoin trough dose is within normal ranges is this acceptable?
Yes this is, the dose is suitable.
What is the recommended sampling time for lithium levels? How often do you need to monitor?
12 hours after last dose.
Weekly and ofter each dose change until levels are stable, then 3 months after.
At what level are you likely to see the toxic effects of lithium manifest?
> 1.5mmol/L
Methotrexate is predominantly excreted how?
Renally
Methotrexate can’t be started if pt has what abnormal tests?
LFTs - Hepatotoxicity
Do you need a baseline CXR before starting methotrexate?
No, but it is recommended.
For Olanzipine and other antipsychotics what tests need to be performed prior to treatment?
Fasting Blood Glucose in all
ECG if pt has cardiovascular disease
(also whole load of others, but not mentioned in PSA)
What blood tests do you need before and during amiodarone therapy?
Full TFTs before and every 6 months
Liver function tests required before treatment and then every 6 months.
Serum potassium concentration should be measured before treatment.
Chest x-ray required before treatment.
Sore throat when taking carbimazole may indicate…?
Agranulocytosis, need to check FBC
Common antibiotics that have adverse drug reactions, and their respective reactions?
Gent and Vancomycin
- Nephrotixicity
- Ototoxicity
Cephalosporins or ciprofoxacin (any abx but these common)
- C diff
ACEI S/Es?
- Hypotension
- Electrolyte abnormalities
- AKI
- Dry cough
Beta blockers S/Es?
- Hypotension
- Bradycardia
- Wheeze in asthmatics
- Worsens acute HF (helps chronic HF)
Calcium channel blockers S/Es?
Hypotension
Bradycardia
Peripheral oedema
Flushing
Diuretics S/Es?
Hypotension
Electrolyte abnormalities
AKI
Heparins Common S/Es?
Haemorrhage
Heparin induced thrombocytopenia
Warfarin S/Es?
Haemorrhage
Aspirin S/Es?
Haemorrhage
Peptic Ulcers
Tinnitus (large dose - ?toxicity)
Digoxin S/Es?
N&V&D
Blurred vision
Confusion
Drowsiness
Yellow/green vision
Amiodarone S/Es?
Interstitial lung disease
Thyroid disease - both ways, similar to iodine amIODarone
Skin greying
Lithium S/Es?
Early - Tremor
Mid - Tiredness
Late - Arrhythmias, seizures, coma, renal failure
Haloperidol S/Es?
Dyskinesias
Clozapine S/Es
Agranulocytosis
Statins S/Es?
Myalgia, Abdo pain, Increased ALT/AST, Rhabdomyolysis
When spotting drug interactions in a question what three type of drugs are normally the culprit?
Drugs with Narrow therapeutic index e.g. Warfarin, Digoxin, Phenytoin.
Drugs that require titration according to effect
- Antihypertensives
- Antidiabetic
- If low GCS or acidotic, look for metformin
Enzyme inducers/inhibitors
In what situation might Trimethoprim put a pt at risk of neutropenia?
If co-prescribed with methotrexate (due to low folate)
At what level of paracetamol overdose do you give NAC before you have seen the paracetamol levels?
> 150 mg/kg
Aspirin, ibuprofen in breast feeding?
Aspirin should be avoided
Ibuprofen okay.
What are the three main drugs to avoid in asthma?
NSAIDS
B-blockers
Adenosine
Digoxin monitoring following prescription for AF?
Ventricular rate at rest
concentration (atl 6 hours after dose) normally before next/second dose
Drugs that interfere with seizure meds?
alcohol, cocaine, amphetamines
ciprofloxacin, levofloxacin
aminophylline, theophylline
bupropion
methylphenidate
mefenamic acid
If trough levels of gentamicin are raised what should you do?
Increase the interval between the doses
What is the toxic dose of paracetamol levels (give NACT immediately)?
150mg per kg
so 60kg is 9000 mg
Approximately what percentage of patients who are allergic to penicillin are also allergic to cephalosporins?
Around 0.5-6.5% of patients who are allergic to penicillin are also allergy to cephalosporins.
Breakthrough pain management for oral morphine?
It is recommended that patients take one-sixth of their total oral morphine dose for breakthrough pain.
What drugs reduce hypoglycaemic awareness?
Beta blockers
Drugs that can cause SIADH?
sulfonylureas
SSRIs, tricyclics
carbamazepine
vincristine
cyclophosphamide
What diabetes meds should you start someone with CKD on?
Not metformin (if GFR below 30)
Gliclazide
COPD acute exacerbation management?
Salbutamol, O2 (28% venturi), Ipratropium, aminophylline
When working out breakthrough pain for opioids that aren’t morphine, what is a good method?
First work out what that opioid is equivalent to, then do 1/6 of the dose in morphine breakthrough/
When prescribing for a UTI, and choosing between nitro and trimeth, what should you take into account?
Pregnancy and breast feeding
eGFR - Nitro should be avoided if below 45
What is the target INR before surgery? What can you give if too hig>
1, if too high can give vit K (phytomenadione)
What to look out for with the efficacy of POP medications?
Enzyme-inducing drugs (PC BRAS. topiramate)
What diabetes meds should you start someone with CKD on?
Not metformin (if GFR below 30)
Gliclazide
COPD acute exacerbation management?
Salbutamol, O2 (28% venturi), Ipratropium, aminophylline
What drug can you withhold in iron deficiency anaemia?
Aspirin
What do you monitor to evaluate the success of fluid therapy?
Blood pressure
What do you monitor for adverse effects in HRT?
Blood pressure
If a trough level is too high what should you do?
Increase the time interval between doses
Beta blocker overdose medicine?
Atropine - If brady
Glucagon if atropine doesn’t work
Drugs to give in antifreeze overdose?
Fomepizole
Organophosphate poisoning overdose management?
Atropine
Classic electrolyte abnormality that can precipitate digoxin toxicity?
Hypokalaemia
oculogyric/dystonic crisis management?
Procyclidine
Drugs to stop in PVD?
Vasoconstrictors, e.g. atenolol,
ACEI in severe PVD
Drugs to stop in heart failure?
Steroids, Calcium channel blockers
First and second line treatment for hypoglycaemia in hospitalised patient?
First is 75ml of 20% glucose
then 1mg IM glucagon
If IV access is not available then it’s glucagon first
Best way to monitor sepsis treatment efficacy?
Resolution of symptoms
Management of rhabdomyolysis in statin treatment?
First stop it, then restart it at a lower dose if symptoms resolve
When do you give prothrombin in warfarin pts?
If there is a heavy bleed causing haemodynamic instability or into a confined space such as the skull
What have you got to avoid in your diet if you start taking statins?
Grapefruit
When should you prescribe pain relief as required and regularly?
If it is constant pain prescribe it regularly. Even if the pt is on the lower rung regularly if it is constant pain add the next rung regularly. Do not add co-codamol if already on paracetamol, add codeine.
When do you dose adjust enoxaparin?
GFR below 30 or weighing less than 50kg
If a pt is oliguric (but not in retention) what is the best choice of fluid prescription?
1 L (n saline) over 2-4hrs
In DKA what do you do in terms of insulin management?
Stop short acting insulin, continue long acting and start fixed rate infusion
In neuropathic pain, what is the first line treatment?
First line is always paracetamol, can go on to others, but try this first
Screening for adverse effects of the COCP is done with what parameter?
Blood pressure
In renal failure what is the best opiate to use?
Oxycodone
Fluid and electrolyte requirements per kg?
25-30ml/kg/day of water
1mmol/kg/day for sodium, chloride and potassium
How long do you observe patients following serious allergic reaction to a drug?
6-12 hours
What are the three steps of the WHO pain ladder?
Step 1:
- Paracetamol (or other non opioid).
Step 2:
- weak opioid and non opioid (co-codamol)
Step 3:
- Strong opioid and non opioid
Plus adjuvants is required
