Clinical Pharmacology, Therapeutics and Toxicology Flashcards
what is the drug in anti-freeze
ethylene glycol
features of ethylene glycol poisoning
stage 1: similar to alcohol, confusion, ataxia, slurred speech
2: metabolic acidosis with high anion gap and high osmolar gap. Also tachycardia and hypertension
3: acute renal failure
Mx of ethylene glycol poisoning
fomepizole (alcohol dehydrogenase inhibitor)
used to use alcohol
haemodialysis in refractory cases
role of somatostatin
inhibits GH, glucagon and insulin release
indications for octreotide
acute variceal haemorrhage acromegaly carcinoid syndrome (flushing, diarrhoea, restrictive cardiomyopathy) post pancreatic surgery VIPomas refractory diarrhoea
features of carcinoid syndrome
flushing
diarrhoea
restrictive cardiomyopathy
secondary to carcinoid tumours (neuroendocrine)
Side effects of ciclosporin
everything increased
BP, fluid, gums, hair, K, glucose
drugs with zero-order kinetics:
metabolism independent of reactant concentration phenytoin salicylates heparin ethanol
how common is a deficiency of hepatic N-acetyltransferase?
which drugs are affected by this?
50% PISHD Procainamide (1a antiarrhythmic) Isoniazid Sulfasalazine Hydralazine (vascular smooth m relaxant) Dapsone
effect of macrolides on other medications
macrolides (erythromycin, clarithromycin, azithromycin)
macrolides inhibit P450 enzymes which metabolise statins, significantly increasing risk of myopathy and rhabdomyolysis therefore stop statins whilst on macrolides
mechanism of action of bezafibrate
SE
PPAR-alpha agonist, increasing lipoprotein lipase expression.
SE: myositis, cholestasis, pruritis
ECG changes of TCA overdose
sinus tachy
wide QRS
prolonged QT interval
how long do you have to take steroids for before needing osteoporosis prophylaxis
prednisolone 7.5mg or equivalent for >3months
how long may it take for finasteride to work?
mechanism of action
SE
can be up to 6 months
5-alpha reductase inhibitors (blocks testosterone -> DHT)
SE: ED, decreased libido, ejaculation problems, gynaecomastia
Mx of Beta blocker OD
atropine and glucagon
glucagon is positively ionotropic and decreases renal vascular resistance
If above fails then pacing
adverse features of cocaine use
Cardiac: MI, tachy or brady, HTN, QRS widening and QT prolongation, aortic dissection
Neuro: seizures, hypertonia, hyperreflexia, mydriasis
psych: agitation, psychosis, hallucinations
other: hyperthermia, metabolic acidosis, rhabdomyolysis
Cocaine
Mechanism of action
Mx
D, NA, and 5HT reuptake inhibitor
Mx: Benzos
BZD + GTN (if chest pain, PCI if MI)
BDZ + sodium nitroprusside (if HTN)
features of paracetamol OD
n&v
24 hrs later: RUQ pain, jaundice, encephalopathy
causes of gingival hyperplasia
ciclosporin
calcium channel blockers
phenytoin
AML
Mx of cyanide poisoning
IV hydroxycobalamin
Dicobalt edetate
inhaled amyl nitrite, IV sodium nitrite (oxidises Fe2 to Fe3, forming methaemoglobin which binds to cyanide)
thiosulphate also used to metabolise cyanide
What is the mode of action of ciprofloxacin?
Bacterial DNA gyrase inhibitors.
What is the mechanism of action of trimethoprim
bacterial folate synthesis inhibitor
