Comprehensive exams for Mental Health Q 144
After taking an overdose of phenobarbital (Barbita), Mario is admitted to the emergency department. Dr. Trinidad prescribes activated charcoal (Charcocaps) to be administered by mouth immediately. Before administering the dose, the nurse verifies the dosage ordered. What is the usual minimum dose of activated charcoal?
A. 5 g mixed in 250 ml of water
B. 15 g mixed in 500 ml of water
C. 30 g mixed in 250 ml of water
D. 60 g mixed in 500 ml of water
Correct Answer: C. 30 g mixed in 250 ml of water
The usual adult dosage of activated charcoal is 5 to 10 times the estimated weight of the drug or chemical ingested, or a minimum dose of 30 g, mixed in 250 ml of water. Doses less than this will be ineffective; doses greater than this can increase the risk of adverse reactions, although toxicity doesn’t occur with activated charcoal, even at the maximum dose. Activated charcoal is widely used in Emergency Departments to treat many types of toxic ingestions. Its use significantly prevents the absorption of many toxic drugs and other poisons if given early post-ingestion.
Option A: An oral suspension of activated charcoal (AC) should merit consideration in poisonings when there is an indication for gastrointestinal decontamination of an ingested toxin, and the clinician can administer activated charcoal within 1 hour of ingestion. When the dose of the ingested toxin is known, experts recommend activated charcoal at a 10 to 1 ratio of activated charcoal to the ingested toxin. This ratio may be impractical to achieve when the patient has ingested large doses of a toxin.
Option B: When the amount of toxin ingested is unknown, or it is impractical to achieve a 10 to 1 ratio in large dose toxic ingestions, SDAC should be administered at a dose of 1g/kg of body weight or using a simplified age-based dosing scheme. Formulations have been attempted to increase the palatability of activated charcoal, which is black and has a gritty texture. Ready-to-use aqueous suspensions of activated charcoal are available in 15 g, 25 g, and 50 g doses as well as formulations premixed with sorbitol.
Option D: Pulmonary aspiration and a resulting aspiration pneumonitis are the most concerning risks of administration of activated charcoal. Aspiration from emesis and misplaced nasogastric tubes for activated charcoal administration can lead to severe respiratory compromise and even death. Therefore, an adequate airway assessment must take place before the administration of activated charcoal.