Pharmacology Flashcards
Which drug can cause ototoxicity and nephrotoxicity?
Which disease is it contrindicated in?
Gentamicin
Myasthenia Gravis
How do you treat beta blocker overdose? What if 1st line doesn’t work?
Give atropine if bradycardic
If doesn’t work, give IV glucagon
(acts on glucagon receptors on heart, bypassing beta blockade)
How do you treat aspirin overdose? What are the criteria for haemodialysis?
IV bicarbonate
Haemodialysis criteria are acidosis, pulmonary oedema, seizure, coma..
What are the symptoms of CO poisoning?
Headache, confusion
Nausea vomiting
Cherry pink lips/mucosa
History of student accommodation/poorly maintained housing
Which investigation in suspected CO poisoning?
ABG!
Not pulse oximetry (will be artificially high from CO)
What symptoms does pesticide poisoning cause and why?
parasympathetic overactivation…
(because it inhibits acetylcholinesterase)
so increase in ACh
bradycardia
salivation
lacrimation
urination
diarrhoea
How to treat pesticide poisoning?
Atropine
Symptoms of lithium toxicity?
Coarse tremor
Acute Confusion
Hyperreflexia
CAH
Which NSAID is contra-indicated in CVS/VAscular disease?
Diclofenac!
Definition of prolonged QTc?
men >440
women >460
> 500 = increased risk TdP
Enzyme inducers
CRAP GPS induces rage
(St Johns wort)
Enzyme inhibitors
SICKFACE.COM Group
(Grapefruit juice)
What is danger of TCA overdose?
How do you treat overdose?
Metabolic acidosis and heart arrhythmia
Therefore, IV bicarbonate
Which medications can’t be used with methotrexate and why?
Trimethoprim
Co-trimoxazole
(they are both folate antagonists)
What medication can’t be given with Viagra?
Nitrates and nicorandil, due to over vasodilation and hypotension risk
What are features of lithium toxicity?
CAH
Coarse tremor (fine tremor at therapeutic levels)
Acute confusion
Hyperreflexia
What is therapeutic and toxic range of lithium?
0.4 - 1 therapeutic
> 1.5 toxicity seen
What can precipitate lithium toxicity?
Dehydration (D+V)
Kidney injury (including NSAID use)
Management of lithium toxicity?
IV Fluids to become euvolaemic
Then run mainatencne fluids at twice normal rate
Check Na 4hrly along with Lithium levels
Dose of adrenaline in anaphylaxis?
1:1000 IM 0.5mg
(in cardiac arrest it is 1:10,000 IV 1mg)
Which drugs cause urinary retention?
TCAs (e.g. amitriptyline)
Anticholinergics
Opioids!
Side effects of metformin?
GI upset
Lactic acidosis, because it promotes anaerobic respiration (particularly issue if preceding event which has caused Ischaemia such as MI)
Side effects of sulphonylureas (gliclazide, glimperide)?
Hypoglycaemia
Weight gain
SIADH!!!
Side effects of pioglitazone?
Fluid retention
Side effect of tamoxifen?
Is a SERM
Therefore through down modulating oestrogen receptors, can mimic symptoms of menopause - i.e. hot flushes!
(Also risk of endometrial cancer)
Which bloods need to be monitored on amiodarone?
TFT and LFTs
(amiodarone contains iodine, disrupts thyroid function and can cause hypo and hyperthyroidism)
(can also cause hepatotoxicity)
Which bloods need to be monitored on lithium?
FBC, UEs, TFTs
(lithium can affect thyroid function - can cause autoimmune Hashimoto’s thyroiditis)
Side effects of amiodarone?
Prolongs QT (is anantiarryhtmic which works by prolonging QT to get help terminate ventricular arrhythmia)
Can cause other arrhythmias however
Thyroid dysfunction
Pulmonary fibrosis
Side effects of TB meds?
Rifampicin - hepatoxicity, orange secretions
Isoniazid - peripheral neuropathy (prevent by giving vit B6 pyridoxine)
Pyrizinamide - hepatotoxicity
Ethambutol - optic neuritis
When should mefloquine not be given?
history of depression/anxiety
(is an anti-malarial)
Antidote to methanol poisoning?
Fomepizole (inhibits alcohol dehydrogenase)
Should you routinely monitor digoxin levels?
No, only If suspect toxicity
Toxicity can occur at normal levels
Symptoms of digoxin toxicity? what can precipitate?
Lethargy
Vision changes - yellow green vision
Nausea
Hypokalaemia
Loop and thiazide diuretics
Rate limiting CCBs (diltiazem, verapamil)
Spironoloactone
Antidote to benzo overdose?
Flumezanil (if cause is iatrogenic e.g. GA)
Otherwise, usually just supportive care. Because if someone who chronically uses benzos, overdoses, flumezanil can cause seizures.
How soon can you test paracetamol after an OD?
4hrs
(time it takes for all the paracetamol to be absorbed - taking any sooner will underestimate extent of overdose)
What are the King’s College Criteria for liver transplantation in paracetamol overdose?
Acidotic after a day
(i.e. pH <7.3 after 24hrs)
OR
All of below:
(basically hepatorenal failure)
PT >100 seconds
Creatinine >300
Grade 3 or 4 encephalopathy
How does metformin work?
Stops liver producing new glucose (gluconeogenesis) and increases insulin sensitivity
When should you not prescribe nitrofurantoin? Why?
- Avoid in third trimester of pregnancy (causes haemolysis of newborn)
- In CKD stage 3 or worse
Nitrofurantoin is a prodrug. Needs bacteria to convert it to active form. Needs to be adequately concentrated by working kidneys - otherwise won’t work. Also will build up in circulation and eventually human enzymes convert it to free radicals which can cause irreversible peripheral neuropathy!
What are the CYp450 inhibitors?
SICKFACES.COM
Sodium Valproate
Isoniazid
Cemitidine
Ketoconazole
Fluconazole
Acute Alcohol + Grapefruit Juice
Ciprolfloxacin
Erythromycin
Sulfsalazine
Chloramphenicol
Omeprazole
Metronidazole
What are the CYP450 inducers?
CRAP GPS
Carbamazapine
Rifampicin
Alcohol (chronic)
Phenytoin
Gleofulvin
Phenobarbitone
Sulfonylureas
What is a side effect of doxycycline?
Photosensitivity
What is a side effect of amoxicillin
Causes maculopapular rash in glandular fever
What do you need to be careful of when prescribing azathioprine/allopurinol?
NEVER PRESCRIBE THE TWO TOGETHER
Azathoprine is prodrug, converted to 6 mercaptopurine. Xanthine oxidise then converts this to uric acid.
Allopurinol inhibits xanthine oxidase, causing build up of 6-MP which causes myelosuppression and potentially neutropenic sepsis!
How soon after overdose can you give activated charcoal?
How soon can you do gastric lavage?
1hr
lavage - 1-2hrs
What are the important vs less important side effects of beta blockers?
IMPORTANT
BRONCHOSPASM
BRADYCARDIA
Less important
headaches
erectile dysfunction
sleep disturbance
insomnia
cold peripheries
Important adverse effects of ciprofloxacin?
Lowers seizure threshold
Achilles tendonitis +/- rupture
What is Herceptin used for and what must you do when using?
HER positive breast cancer
Can cause cardiomyopathy, so needs Echo prior to treatment and during, to check LVEF.
What are the symptoms/signs of aspirin toxicity?
Classic picture of mixed respiratory alkalosis (as resp centre stimulated initially) and metabolic acidosis (direct effect of drug plus renal failure it causes)
Can cause tinnitus due to ototoxicity
(aminoglycosides can also do this)
Which bloods need to be monitored with statin use in first 12 months, aside from lipids?
LFTs
(CK not indicated unless muscle symptoms)
Aside from thyroid dsyfunction, pulmonary fibrosis, hepatotoxicity, long QT, what other side effects can amiodarone cause?
Ocular - corneal opacities, optic neuritis
Side effects of aminoglycosides?
Includes gentamicin and amikacin
they cause nephrotoxicity and ototoxicity
CAN’T BE USED IN MYASTHENIA GRAVIS
What blood test needs to be monitored when on pioglitazone or sodium valproate?
LFTs
(as do TB drugs, amiodarone, statins)
Can you take Lithium in pregnancy?
No! It causes Ebstein’s anomaly = atrialization of right ventricle
Mechanism of action of aspirin?
Non reversible COX 1 and 2 inhibitor, so reduces production of prostaglandins and thromboxane A2
