6343295
Description
Flashcards by Andrew Street, updated more than 1 year ago
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Created by Andrew Street
about 8 years ago
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| Question | Answer |
| Indications for activated charcoal. | Indications: • A single dose of activated charcoal may be used to reduce absorption of certain poisons (including some drugs in OD) from the gut • Multiple doses of activated charcoal may also be used to increase the elimination of certain poisons |
| MOA of activated charcoal. | MOA: Van der Waals (weak intermolecular) forces are responsible for the mechanism of action of activated charcoal. Molecules are adsorbed onto the surface of the charcoal as they travel through the gut, reducing their absorption into the circulation. Activated charcoal is only useful where the poison will be adsorbed onto it. The affinity of a substance for activated charcoal is determined by its ionic status and its solubility in water. Weakly ionic, hydrophobic substances (e.g. benzodiazepines, methotrexate) are generally well adsorbed to activated charcoal. By contrast, strongly ionic and hydrophilic substances (e.g. strong acids/bases, alcohols, lithium and iron) are not adsorbed. Activated charcoal can also increase the elimination of certain poisons. This may be useful for substances adsorbed by charcoal that can readily diffuse back into the gut. In this case, multiple doses of activated charcoal can be used to maintain a steep concentration gradient of the poison (high in the circulation, low in the gut), encouraging diffusion out of the circulation (aka 'gut dialysis'). |
| SE's of activated charcoal. | SE's: • Aspiration can lead to pneumonitis, bronchospasm, airway obstruction • GI obstruction • Black stools • Vomiting |
| CI's, cautions, & important drug interactions of activated charcoal. | CI's: • None Cautions: • Pt's with ↓ LOC unless they're intubated to protect airway • Pt's with persistent vomiting - as at risk of aspiration • Pt's with ↓ GI motility - risk of obstruction Important interactions: Activated charcoal prevents absorption of many drugs taken therapeutically as well as those taken in overdose. |
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