Indications, Mechanisms, Adverse And Warnings Flashcards
Acetylecysteine mechanism
Replenishes supply of glutathione
Also antioxidant - why helps in contrast nephropathy
Adverse effect when large dose of Acetylcyteine for paracetamol poisoning
Anaphylactic
When Acetylcyteine administered as mucolytic what is a possible adverse reaction
Bronchospasm
Acetylcyteine dose for contrast nephropathy prophylaxis
600-1200mg 12 hourly for 2 days
Acetylcyteine dose for mucolysis
2.5-5 ml 10% solution by nebuliser every 6 hours
Acetylcyteine dose for paracetamol poisoning
Slow drip over 21 hours - consult BNF
Monitoring for paracetamol poisoning after Acetylcyteine
INR most sensitive marker for ongoing liver injury
ALT, creatinine conc
Activated charcoal uses
Reduce absorption of certain poisons / drugs in overdose from gut
Increase elimination of poisons (if readily diffuse back into gut)
Mechanisms of activated charcoal
Molecules are adsorbed onto surface of charcoal -> reduced absorption
Activated charcoal adverse effects
Black stools and vomiting
Intestinal obstruction
Aspiration -> pneumonitis, bronchospasm, airway obstruction
Who shouldn’t get activated charcoal
Reduced consciousness / persistent vomiting (aspiration)
Reduced GI motility (obstruction)
How do you prescribe Activated charcoal
Within 1 hour of injection of clinically significant amount of substance
50g orally in 250ml water suspension (drink)
When use adenosine
Supraventricular tachycardia
Adenosine mechanism
Increases AV node refractoriness -> breaks re entry circuit -> allows normal depolarisation
Adenosine adverse effects
Bradycardia - often like ‘sinking feeling in chest’ ->
Breathlessness
Who can’t receive adenosine
Hypotensive, Coronary ischemia, Decompensated heart failure (bradycardia)
Asthma (bronchospasm)
Heart transplant - very sensitive to effects
What blocks uptake of adenosine?
Effect?
Dipyridamole -> prolongs effect (should half dose)
Adenosine prescribing
6mg IV - increased to 12 if ineffective
What’s needed for administration of adenosine
Resuscitation facilities
What to tell patient p you are giving adenosine
Hopefully ‘reset heart’ to normal
Will make them feel terrible for about 30 seconds
Monitoring for adenosine
Continuous cardiac rhythm strip
Adrenaline uses
Cardiac arrest
Anaphylaxis
Local - vasoconstriction (eg stop mucosal bleeding), prolong local anaesthesia (with lidocaine)
Adrenaline mechanism
Agonist a1,a2,b1,b2
- > redistribution of blood favouring heart
- > bronchodilation and suppression of inflammatory mediator release from mast cells
Adrenaline adverse effects
Hypertension, tremor,manliest, headache, palpitations, arrythmias, angina
When should adrenaline not be used
Areas supplied by end artery (eg fingers and toes) -> necrosis
Cautious in heart disease
Adrenaline interactions
B blocker -> widespread vasoconstriction
Adrenaline prescription for cardiac arrest
1mg IV after third shock
Repeated every 3-5 mins after
Adrenaline prescription anaphylaxis
500mg IM
Aldosterone antagonists uses
Ascites and odema due to liver cirrhosis
Chronic heart failure
Primary hyperaldosteronism
Aldosterone antagonists adverse effects
Hyperkalaemia -> weakness, arrythmias
Gynaecomastia
When not to use aldosterone antagonists
Hyperkalaemia
Addison’s disease
Renal impairment
Breastfeeding women - crosses into milk
Aldosterone antagonists interactions
Potassium elevating drugs (ACEi, ARBs)
Eg of aldosterone antagonists
Spironolactone
(epleronone - only for heart failure)
Starting dose of spironolactone Ascites? Heart failure?
100mg daily for ascities
25mg daily for heart failure
What to tell men getting spironolactone
Growth and tenderness of tissue under vessels
Impotence
Benign and reversible
Issue with spironolactone effects? How to counteract
Takes several days for effect -> prescribed with a loop / thiazide diuretic
Alginates and antacids uses
GORD
Dyspepsia
How do alginates work
Increase viscosity of stomach contents
How do ant acids work
Buffer stomach acids
Eg of antacids
Sodium bicarbonates
Calcium carbonates
Magnesium salts
Aluminium salts
Antacid adverse effects
Magnesium - constipation
Aluminium - diarrhoea
When not to use alginates
Thickened milk preparations
Sodium / potassium antacids should not be used when?
Fluid overload / Hypercalcaemia eg. Renal failure
Alginates interactions ? How to prevent
Reduce serum conc of many drugs
- check book
Take at different times gap of at least 2 hours
Eg of name alginates and antacids
Gaviscon
Peptac
Allopurinol uses
Prevent acute attacks of gout
Prevent Uric acid and calcium oxalate renal stones
Prevent hyperuricaemia and tumour lysis syndrome associate with chemo
Mechanism of allopurinol
Xanthine oxidase inhibitor
Allopurinol adverse effects
Skin rash - maybe Stevens Johnson syndrome
Can trigger / worsen acute gout attack
When should allopurinol be avoided
Acute attacks of gout
Recurrent skin rash / signs of hypersensitivity
When should allopurinol dose be reduced
Renal / hepatic Impairment as excreted / metabolised
Allopurinol interactions
Mercaptopurine (and pro-drug azathiopine) as use xanthine oxidase
How is allopurinol prescribed
100mg daily oral. Titrate up according to serum Uric acid
When starting allopurinol for gout what else should be prescribed
NSAID / colchicine
When should allopurinol be started when used with chemo
Before chemo starts
When should allopurinol be taken
After meals - encourage good fluid intake 2-3 l per day
What should be told to patients getting allopurinol
Seek medical advice if they get a rash
Target of Uric acid concentrations with allopurinol
Which drugs increase serum Uric acid
Thiazide and loop diuretics
Low dose aspirin inhibits renal Uric acid excretion
Egs of alpha blockers
Doxazosin
Tamsulosin
Alfuzosin
Alpha blockers use
Benign prostatic hyperplasia
Add on treatment in resistant hypertension
Mechanism of alpha blockers
Highly sensitive to a1 (mainly smooth muscle)
-> vasodilation and reduced resistance to bladder outflow
Alpha blockers adverse effects
Postural hypotension
Dizziness
Syncope
When should alpha blockers not be used
Patients with postural hypotension
Doxazosin dose
1mg daily and increased at 1-2 week intervals dependent on response
Tamulosin only licensed for? Dose?
BPH
400mg daily
When is doxazosin ideally administered
Bed time - due to blood pressure lowering
Aminogycosides eg
Gentamycin
Amikacin
Amino glycosides uses
Severe sepsis
Pyelonephritis / complicated UTI
Biliary / intraabdominal sepsis
Endocarditis
Organism unknown in endocarditis - what should be given with amino glycosides
Penicillin / metronidazole
Mechanism of aminoglycosides
Bind irreversibly to bacterial ribosomes
Aminoglycosides adverse effects
Nephrotoxicity and ototoxicity
How does nephrotoxicity present
Reduced urine output and rising serum creatinine / urea
How does ototoxicity present
Hearing loss, tinnitus, vertigo
MAY BE IRREVESIBLE
Be careful with aminoglycosides in
Neonate, elderly, renal impaired Myasthenia gravis (can impair neuromuscular transmission)
When is ototoxicity more likely with aminoglycosides
When prescribed with loop diuretics / vancomycin
When is nephrotoxicity more likely with aminoglycosides
Prescribed with Vancomycin / cephlasopins
How are aminoglycosides administered
IV - can’t give oral as highly polarised (don’t cross lipid membrane)
Why are aminoglycosides diluted and administered slowly
Prevents ear exposure to high concentrations
What to tell patients with aminoglycosides
Tell you if any ringing / hearing changes / dizziness
Acetylcysteine indications
Paracetamol poisoning
Prevent renal injury during contrast nephropathy
Reduced viscosity of respiratory secretions
Amionosalicyates use
Ulcerative colitis
Rheumatoid arthritis
Eg of aminosalicyates
Mesalazine
Sulfasalazine
Aminosalicyates mechanism
Release 5-aminosalicylic acid -> anti inflammatory and immunosuppressive effects
Aminosalicyates adverse effects
GI upset
Headache
Rarely - thrombocytopenia / leucopenia, renal impairment , reduced sperm count
Hypersensitivity
Who should not take aminosalicyates
People with aspirin hypersensitivity (both are salicyates)
Aminosalicyates drug interactions
PPI - may cause coating to be broken down early
Lactulose - lowers stool ph -> may prevent release
Acute attack of UC how is mesalazine prescribed
Suppository 1-2 times daily for 4-6 weeks
Can be taken orally
What should be checked in patients getting oral mesalazine
Renal function
What should be checked in patients getting sulfasalazine
FBC and liver profile
Which aminosalicyates causes the lease adverse effects
Mesalazine
