Pharmacology / toxicology Flashcards
ACEi angioedema
1) remove the drug
2) supportive airway protection
3) drug options: C1 esterase inhibitor concentrate / FFP / tranexamic acid
Antiemetic in last days of life
Levomepromazine - multiple pathways
Prokinetic antiemetics
Domperidone - does not cross BBB, reduced extrapyramidal symptoms
Metoclopramide
Rifampicin effect on steroids
Reduces availability
Lithium overdose features
Coarse tremor, hyperreflexia, confusion, seizure, coma
Lithium overdose mx
Mild - IV saline
IV sodium bicarbonate
haemodialysis if severe
Interferon beta
1st line RR-MS treatment (reduce frequency / severity of relapses)
Contraindicated in liver disease - use glatiramer
Cytochrome P450 inhibitors
6A, ISRV
Antibiotics: ciprofloxacin, erythromycin Amiodarone Allopurinol Alcohol (acute) Anti-acids: omeprazole, cimetidine Azoles: ketoconazole, fluconazole
Isoniazid
SSRIs: fluoxetine, sertraline
Ritonavir
Valproate
Cytochrome P450 inducers
A B C R Smoking S
Antiepileptics: phenytoin, carbamazepine (but not valproate!)
Barbiturates: phenobarbitone
Chronic alcohol intake
Rifampicin
St John’s Wort
Smoking (affects CYP1A2, reason why smokers require more aminophylline)
Griseofulvin
Cinchonism
= quinine toxicity
flash pulmonary oedema ECG changes: arrhythmias, prolonged QTc, broad QRS hypotension seizures tinnitus visual disturbance metabolic acidosis
Long term: renal failure
Mx: IV fluid, bicarb, supportive. Haemofiltration does not remove toxin
Anti TB drugs and their side effects
Rifampicin: cytochrome inducer, hepatitis, orange secretions, rash, flu-like symptoms
Isoniazid: cytochrome inhibitor, peripheral neuropathy (need pyridoxine), psychosis, hepatitis, agranulocytosis
Pyrazinamide: hyperuricaemia -> gout, arthralgia, myalgia, nausea, hepatitis
Ethambutol: optic neuritis, rash, need to dose adjust in renal impairment
Iron overdose symptoms
Symptoms over 20mg/kg
- GI corrosion: abdo pain, vomiting, diarrhoea, GI bleeding
- hyperglycaemia -> hypoglycaemia
- metabolic acidosis with high anion gap
- iron depsoition in organs -> cardiac failure, encephalopathy, liver failure
- renal failure
Fatal 200mg/kg
Mx iron overdose
- bowel decontamination
- deferoxamine
- treat if: shock, low gcs, persistent GI symptoms, metabolic acidosis, pills on radiograph, serum iron > 500mcg/dl or dose > 60mg/kg iron
Anticoagulation when egfr <30
NOACs e.g. rivaroxaban (15mg/day), edoxaban (30mg OD), apixaban (2.5mg BD)
Risks with zidovudine
- mitochondrial dysfunction -> dilated cardiomyopathy
Maximum lidocaine dose as local anaesthetic
3mg/kg
Treating VTE with egfr <30
- <15 -> IV unfractionated heparin
- 15-30 -> 1mg/kg/day enoxaparin
Organophosphate poisoning
Features secondary to ACh (SLUD)
- salivation
- lacrimation
- urination
- diarrhoea
- CV (hypotension, brady)
- miosis
- muscle fasciculation
Mx: atropine
Salicylate overdose
Features
- mixed respiratory alkalosis and metabolic acidosis
- hyperventilation
- tinnitus
- lethargy
- nausea / vomiting
- sweating
- BM changes
- seizure
- coma
Mx:
- charcoal
- IV bicarb
- haemodialysis (esp if ARF, pulm oedema, CNS)
TCA overdose
Worst causes: amitriptyline, dosulepin
Features
- anticholinergic: dry mouth, mydriasis, agitation, tachycardia, blurred vision
- arrhythmias
- seizure
- metabolic acidosis
ECG
- tachycardia
- widening QRS
- QT prolongation
Mx
1) IV bicarb
2) ?IV lipid emulsion
No role of dialysis
Beta blocker overdose mx
1) atropine
2) glucagon
Ethylene glycol / methanol OD mx
1) fomepizole
2) dialysis
Local anaesthetic toxicity
Features
- reduced GCS, seizure
- CV: arrhythmias, hypotension
Mx: IV lipid emulsion
