You recieve a handover from your junoir of a lady with history of sucidal attempt by overdose of multiple medications including antidepressant and .She presented to ED 4 hours after ingestion. She was drowsy but normal with vitals .
She had NGT inserted and activated charcoal (AC) given.
You were unhappy about the decision and wanted to explain to your junoir why
Q1 List the contraindications for AC including what this patient had?
Q2 What substances/drugs are not adsorbed by AC?
Black Medicine , Cont’
Thanks to all of you for the excellent comments
AC is s a highly adsorbent powdered material made from distillation of wood pulp. It have very large surface area , it is highly effective in adsorbing most of the toxin in ration to charcoal to toxin ( 10:1). In some toxins like cyanide ratio may go higher like (100:1). Dose is 1 gram/kg.
This is and example of the AC we have and if anyone interested in trying it let me know 😎 , it is tasteless but could taste good with chocolate pudding
Indications:
1-In general, the risk of poisoning should justify the risk of charcoal administration
2- It should be given within 1 hour of ingestion and sometimes upto 2 hours if the ingestion is known to delay gastric emptying
3- If there are no contraindications
4. Sometimes it is used as multiple dose activated charcoal to enhance elimination from enterohepatic /entroenteric circulation e.g carbamazepine , phenytoin, salicylate
Contraindications:
1- Known/suspected GI obstruction or perforation
2- If the airway is not protected or the patients is drowsy due to risk of aspiration
3- Is the substance taken is not adsorbed by charcoal
In this lady AC was contraindication as she was drowsy and presented late and NGT was inserted to give AC which could have increased her risk of aspiration and complication as well. She also had iron which is not adsorbed by AC . However ,if there is co ingestion with other substances that is adsorbed by AC , it can be given if no contraindications.
PHALES mnemonic can be used to remember drugs that are not adsorbed by AC as well as contraindications
P – Pesticides, petroleum distillates, unprotected airway
H – Hydrocarbons, heavy metals, >1 h
A – Acids, alkali, alcohols, altered level of consciousness, aspiration risk
I – Iron, ileus, intestinal obstruction
L – Lithium, lack of gag reflex
S – Solvents, seizure
References:
1- Poisoning & Drug Overdose , Kent Olson 6th edition