Corrections 2 Flashcards
How often should digoxin levels be monitored?
Digoxin level is not monitored routinely, except in suspected toxicity.
Management of hypomagnesaemia?
If <0.4, or tetany, arrhythmias, or seizures–> IV magnesium sulphate
If >0.4 –> oral magnesium salts
What is a key side effect of oral magnesium salts?
Diarrhoea
Features of hypomagnesaemia?
Features may be similar to hypocalcaemia:
- paraesthesia
- tetany
- seizures
- arrhythmias
- decreased PTH secretion → hypocalcaemia
- ECG features similar to those of hypokalaemia
- exacerbates digoxin toxicity
What is a key feature on an ECG in TCA overdose?
QRS widening, due to sodium channel blockade.
This can be associated with ventricular arrhythmias and cardiac arrest.
What is Ethylene glycol?
Ethylene glycol is a type of alcohol used as a coolant or antifreeze
Management for Ethylene glycol toxicity?
fomepizole (this is an inhibitor of alcohol dehydrogenase)
Management of carbon monoxide poisoning?
Hyperbaric oxygen
Which NSAID is associated with a significantly increased risk of cardiovascular events?
Diclofenac
Contraindications of diclofenac?
1) ischaemic heart disease
2) peripheral arterial disease
3) cerebrovascular disease
4) congestive heart failure (New York Heart Association classification II-IV)
In patients with MI secondary to cocaine use, what should they be given as part of acute (ACS) treatment?
IV benzodiazepines
Give 3 drug causes of gingival hyperplasia
1) phenytoin
2) ciclosporin
3) calcium channel blockers (especially nifedipine)
Why should verpamil not be used alongside beta blockers?
As may cause heart block
Which CCB is most negatively inotropic?
Verapamil
Which CCBs result in ankle swelling?
Nifedipine, amlodipine & felodipine
Why can nifedipine result in reflex tachycardia?
Due to peripheral vasodilation
Name the inducers of the P450 system (6)
Carbamazepine
St John’s Wort
Chronic alcohol intake
Rifampicin
Barbiturates: phenobarbitone
Smoking
Name the inhibitors of the P450 system (9)
Erythromycin
Ciprofloxacin
Sodium valproate
Acute alcohol intake
Isoniazid
Amiodarone
Imidazoles: ketoconazole, fluconazole
SSRIs: fluoxetine, sertraline
Allopurinol
Management of heparin-induced thrombocytopenia (HIT)?
Switch to direct thrombin inhibitor e.g. argatroban
Is bleeding more common with LMWH or UH in those with severe renal impairment?
LMWH
Anticoagulant of choice in those with severe renal impairment?
UH
Organophosphates stimulate sympathetic and parasympathetic nervous systems.
However, in clinical practice and in typical scenarios, what presentation predominates?
Overstimulation of the parasympathetic system predominates.
Key features of organophosphate poisoning: DUMBELS
D - defaecation & diaphoresis
U - urinary incontinence
M - miosis (pupil constriction)
B - bradycardia
E - emesis
L - lacrimation
S - salivation
How do organophosphates affect HR?
Bradycardia
What is a key side effect of diclofenac?
Significantly increased risk of cardiovascular events compared with other NSAIDs.
Contraindications for diclofenac?
ischaemic heart disease
peripheral arterial disease
cerebrovascular disease
congestive heart failure
Which NSAIDs have the best cardiovascular risk profiles?
Naproxen & low dose ibuprofen
What is the Yellow Card scheme?
The standard way to report adverse reactions to medications
What should be reported in the Yellow Card scheme?
1) all suspected adverse drug reactions for new medicines (identified by the black triangle symbol)
2) all suspected adverse drug reactions occurring in children, even if a medicine
What is a black triangle drug?
A black triangle indicates that the medication is new to the market, or that an existing medicine is being used for a new reason or by a new route of administration.
What is the most appropriate time to take blood samples for therapeutic monitoring of digoxin levels?
At least 6 hours after last dose
What is the most appropriate time to take blood samples for therapeutic monitoring of phenytoin levels?
Immediately before next dose
How can amiodarone affect the thyroid?
Hypothyroidism and thyrotoxicosis
In patients with HTN and gout requiring a 2nd antihypertensive (after ACEi), what is recommended next?
Amlodipine.
Why are thiazide-like diuretics not indicated in gout?
Thiazide-like diuretics can lead to hyperuricemia and therefore exacerbate the incidence of gout in patients who are already diagnosed or at high risk.
In amiodarone induced hypothyroidism, what is the management?
Continue amiodarone and add levothyroxine
Which CCB is most likely to precipitate pulmonary oedema in a patient with known chronic heart failure?
Verapmil –> egative inotropic effects, meaning it decreases the strength of heart muscle contraction.
How does digoxin toxicity affect K+?
Hyperkalaemia
How does digoxin toxicity lead to hyperkalaemia?
As digoxin inhibits the Na-K pump, so less potassium can be pumped into cells, and thus, extracellular potassium increases.
Relationship between potassium levels and digoxin?
Hypokalaemia predisposes to digoxin toxicity.
Digoxin toxicity results in hyperkalameia.
How may digoxin toxicity affect appetite?
Loss of appetite and interest in food (anorexia)
When is immediate acetylcysteine treatment indicated in paracetamol overdose with presentation 8-24 hours after ingestion?
If overdose was more than 150 mg/kg, even if the plasma-paracetamol concentration is not yet available
What is 1st line for patients with ischaemic heart disease?
Aspirin
How long should you wait after starting metformin before increasing dose?
1 week
What is a key side effect of ethambutol (TB drug)?
Optic neuritis –> visual acuity testing before and during treatment
What investigation should be done before starting Herceptin (Trastuzumab)? Why?
ECHO - as cardiotoxicity is a common side effect
What is a common cause of drug-induced urticaria?
Aspirin (and other salicylates)
What is the most important antidote in organophosphate poisoning?
Atropine
Role of atropine in organophosphate poisoning?
It competitively limits cholinergic activation
What investigation should be done before using flecainide?
ECHO - to look for signs of structural heart disease.
What routine monitoring is there for patients on digoxin?
No routine monitoring
Features of organophosphate poisoning?
Meumonic: SLUD
Salivation
Lacrimation
Urination
Defecation/diarrhoea
CVS: hypotension, bradycardia
Also: small pupils, muscle fasciculation
How does salicylate poisoning affect acid base balance?
First causes respiratory alkalosis, then metabolic acidosis
What routine monitoring is required for LMWH?
No routine monitoring, but in special situations (e.g. obesity, renal impairment or pregnancy), monitoring of Factor Xa levels can be done.
Management of widened QRS or arrythmia in TCA overdose?
IV bicarb
What class of medication is amiloride?
Potassium sparing diuretic –> epithelial sodium channel blocker
Is bleeding more common with LMWH or UH among patients with severe renal impairment?
LMWH
If the patient is opioid naive, what is the usual starting dose of immediate release morphine (oramorph)?
5mg PRN up to 4 hourly
What is the conversion of codeine dose to morphine?
Divide by 10
When is it appropriate to convert a patient from co-codamol to morphine?
If the patient has been on maximum strength co-codamol (30/500mg two tablets QDS), then it is appropriate to convert this to modified release morphine.
If a patient has been on 30/500mg two tablets QDS of co-codamol, convert this to a morphine MST dose
30/500mg –> use the 30mg (as this is codeine dose)
30x2 = 60mg (as patient is taking 2 tablets)
60x4 = 240mg (as QDS)
240/10 = 24mg PO morphine
/2 = 12mg MST BD
Round to 10mg MST BD
What should all patients on modified release morphine have?
Immediate release morphine available PRN for breakthrough pain.
A patient with lung cancer and bone metastases is taking MST 40mg bd, movicol and ibuprofen.
Over the last week he has required on average 3 doses of 10mg of oramorph for break through pain in his chest. The oramorph works well for the pain after about ½ hour and he has no adverse effects.
What are 2 suitable management plans?
1) Titrate dose upwards by 30-50% increments
40x2=80
80x1.3 = 104mg
104/2 =52 –> round to 50mg BD (new dose)
OR
40x2=80mg
80x1.5=120mg
120/2=60mg BD (new dose)
2) Add daily oramorph dose to background dose
3x10=30mg
80+30=110
110/2 = 55mg BD (new dose)
What is the 1st line opioid for patients with moderate renal impairment?
Oxycodone
eGFR <50 –> use oxygodone
If the eGFR is <12, what is the 1st line opioid?
Alfentanil or fentanyl.
What is the conversion between morphine and oxycodone?
Divide the morphine dose by 2 to calculate oxycodone dose.
What is the mechanism of action of octreotide used to treat acromegaly?
Somatostatin analogue that blocks the production of GH.
What medications can be used to manage an oculogyric crisis? (2)
Benzotropine or procyclidine
Top 3 medications for motion sickness?
1) Hyoscine (e.g. transdermal patch): most effective but use is limited due to side effects
2) Non-non-sedating antihistamines –> cyclizine > promethazine
Management of taking aspirin in a dental procedure?
continue taking anti-platelets as normal
What is important in patients with symptomatic caustic ingestion (i.e. bleach)?
Endoscopy & CT scan
1st line management of methanol poisoning?
Fomepizole or ethanol
Haemodialysis
1st line management of ethylene glycol poisoning?
Fomepizole (an inhibitor of alcohol dehydrogenase)
where is ethylene glycol found?
E.g. antifreeze
What class of diuretics can precipitate lithium toxicity?
Thiazides
Which antihypertensive can cause peripheral vasodilation which may result in reflex tachycardia?
Nifedipine
1st line management of organophosphate insecticide poisoning?
IV atropine
Which diuretics may cause precipitation of digoxin toxicity?
Thiazides
The following symbol appears in the British National Formulary: PoM
What does it mean?
Prescription only medicine
Management of suspected digoxin toxicity?
Temporarily cease digoxin, remeasure conc within 8-12 hours after last dose
