Charcoal

Common Name(s): Activated charcoal, Animal charcoal, Charcoal, Gas black, Lamp black, Oral charcoal adsorbent

Medically reviewed by Drugs.com. Last updated on Jan 1, 2023.

Clinical Overview

Use

Activated charcoal's main use is as an antidote in poisoning. It is promoted for use as an antiflatulent and in dyslipidemia, and has demonstrated benefit in wound healing, kidney disease, and diarrhea/gut dysbiosis. Activated charcoal is also commonly used in toothpastes and as a fine powder for brushing teeth. However, clinical studies to support these uses are lacking.

Activated charcoal's main use is as an antidote in poisoning; this is considered a medicinal use and should only be administered under medical supervision in an appropriate setting. The American Academy of Pediatrics does not recommend administration of activated charcoal in the home, especially in cases of acute poisoning in children.

Dosing

Clinical studies are lacking to provide dosing information for activated charcoal.

Contraindications

The American Academy of Pediatrics does not recommend administration of activated charcoal in the home, especially in cases of acute poisoning in children.

Charcoal is contraindicated in individuals with unprotected airways and decreased levels of consciousness if not intubated; after ingestion of acids or alkalis; cases in which the risk or severity of aspiration is increased; or after isolated ingestion of lithium, iron, heavy metals, or ethanol.

Pregnancy/Lactation

Avoid use. Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

Emesis is the most common adverse reaction. Use in poisoning is associated with a risk of aspiration and subsequent chemical pneumonitis. GI obstruction can develop in patients receiving repeated doses.

Caution should be used in those at risk of gastric hemorrhage or perforation, or in those who have ingested a substance that increases the risk of sudden onset of seizures or sudden decreases in mental status.

Toxicology

Minimal toxicity is associated with the use of charcoal in hemoperfusion.

Source

Charcoal is produced by pyrolysis and high temperature oxidation of organic materials. Animal charcoal is obtained from items such as charred bones, meat, and blood. Activated charcoal is obtained from charred wood or vegetable matter and treated with various substances to increase its adsorptive power. Amorphous carbons (or charcoals) are taken from the incomplete combustion of natural gas, fats, oils, or resins.(Lapus 2007)

History

Charcoal has been used for medicinal purposes for thousands of years. Ancient Egyptian papyri document use of charcoal as early as 1500 BC for the adsorption of odor from rotting wounds. Hindu documents from 450 BC record the use of charcoal and sand filters for the purification of drinking water. Hippocrates and Pliny describe the use of charcoal to treat epilepsy, chlorosis, and anthrax.(Lapus 2007)

In 1773, the German-Swedish pharmaceutical chemist Carl Scheele recognized the specific adsorptive powers of charcoal with various gases. At a meeting of the French Academy of Sciences in 1831, a pharmacist ingested several times the lethal dose of strychnine with equal amounts of charcoal and survived. However, the Academy members were unimpressed by this demonstration, and charcoal continued to be used primarily for industrial purposes.(Lapus 2007)

In 1911, the first industrially activated charcoal was made in Austria. Shortly afterward, the use of toxic gases in World War I drove the mass production of activated charcoal suitable for respirators. However, it was not until 1963, after a review article was published in the Journal of Pediatrics, that activated charcoal became more widely accepted in the management of ingested toxins.(Lapus 2007)

Chemistry

The chemistry of charcoal is complex. Although the purest forms essentially consist of all carbon, the small amounts of impurities that remain following combustion of the source material have been difficult to characterize. Medicinal charcoals have been developed with a high surface area-to-weight ratio in order to maximize adsorption capacity. The adsorptive properties of charcoal can be increased by treatment with substances such as carbon dioxide, oxygen, air, steam, sulfuric acid, zinc chloride, or phosphoric acid (or combinations of these) at high temperatures (500 to 900°C). These materials help remove impurities and reduce the particle size of carbon, allowing more adsorption due to increased surface area. One milliliter of finely subdivided and activated medicinal charcoal has a total surface area of approximately 1,000 m². Medicinal or activated charcoal is a fluffy, fine, black, odorless, and tasteless powder without gritty material. It is insoluble in water or other common solvents but may be suspended for a short time after vigorous shaking.(Gennaro 1995)

Uses and Pharmacology

Acute poisoning antidote

Activated charcoal has been used in the management of acute toxicity for almost a century. Its large surface area permits the adsorption of a variety of complex chemicals, thereby rendering toxic material unavailable for systemic absorption. In addition, charcoal may interrupt the enterohepatic circulation of compounds excreted into the bile. It is usually coadministered with a laxative, which may hasten the elimination of toxins from the GI tract, resulting in diarrhea and more rapid GI transit time.(Juurlink 2016)

The use of activated charcoal in the treatment of poisoning is associated with a risk of aspiration and subsequent chemical pneumonitis. Activated charcoal for this use should only be administered under medical supervision.

Charcoal products sold for dental/oral health or other purposes are not appropriate for use in the management of acute poisoning. The American Academy of Pediatrics does not recommend administration of activated charcoal in the home, especially in cases of acute poisoning in children.(AAP 2003)

Dental and oral health

Clinical data

A randomized controlled crossover trial in 25 healthy participants demonstrated significantly lower tooth wear (P=0.004) and plaque (P<0) when a toothbrush with charcoal-infused nylon bristles was used for toothbrushing for 6 weeks compared with regular nylon bristles. No significant difference in gingival index scores was observed between toothbrushes. Teeth were brushed with a fluoridated dentifrice for 2 minutes during each phase of the study.(Kini 2019)

In a noncomparative study in which 60 young adults used a charcoal dentrifice (toothpaste) twice a day for 8 weeks, a number of oral health markers improved. Compared to baseline, improvements were documented for dental plaque (36% lower), tooth sensitivity (91% lower), and pain on probing (97% lower) at month 3. Additionally, enamel remineralization assessments demonstrated improvement in resistance to acid (by 48% at month 2), and 33% of patients experienced whitening of up to 1 tone. The anticaries index remained unchanged.(Chirkova 2018)

Diarrhea/Intestinal microbiome protective effects

Clinical data

Limited studies evaluating the use of activated charcoal in irinotecan-induced diarrhea showed reduced severity of diarrhea, resulting in a parallel reduction in loperamide consumption.(Michael 2004, Sergio 2008)

A randomized, controlled, single-blind study investigated the effects of a proprietary charcoal product on antibiotic-induced gut dysbiosis in 44 healthy volunteers with a body mass index (BMI) of less than 30 kg/m². Participants received a 5-day regimen of the fluoroquinolone antibiotic moxifloxacin (with or without activated charcoal) or control (activated charcoal alone or nonactive substitute [negative control]). Coadministration of the delayed-release activated charcoal product prevented intestinal dysbiosis and maintained the gut microbiome richness to within 98% of baseline, which was comparable to untreated controls. The protective effect on gut microbiome was maintained for up to 16 days after antibiotic discontinuation. The marked microbiome composition changes observed in the moxifloxacin group were not observed in the activated charcoal alone or negative control groups.(de Gunzburg 2018)

Dyslipidemia

Animal data

In a study evaluating the effect of charcoal on induced atherosclerosis secondary to nephrectomy in rats, no effect on serum cholesterol or triglycerides was noted.(Yamamoto 2011)

Clinical data

Clinical studies from the 1970s and 1980s suggest that charcoal has an effect on dyslipidemia. Reductions in blood lipid levels have been observed in patients with uremia treated with charcoal hemoperfusion, and repeated oral doses of activated charcoal were effective in reducing blood lipid concentrations in patients with uremia(Friedman 1977) and diabetes.(Manis 1980) In a study of hypercholesterolemic patients given activated charcoal, total cholesterol and LDL cholesterol levels decreased. HDL cholesterol and the HDL to LDL ratio increased.(Kuusisto 1986) This study resulted in an increased interest in the use of oral charcoal for the reduction of blood lipid levels, but there is insufficient evidence to confirm the effect on lipid parameters or to determine an appropriate dose.

Face mask toxicity

Clinical data

Based on data collected from a study conducted in China, wearing face masks made from binchotan charcoal fibers for 20 minutes led to a significantly lower accumulation of toxic chemical residues (ie, phenoxyethanol, methylparabens) from the masks compared with bio-cellulase–, bamboo charcoal fiber–, and plant cellulose–based masks (P<0.05). A 20% increase in exposure amount was observed when consumers switched from the binchotan charcoal–based mask to the plant cellulose–based mask. A dramatic increase was also seen when masks were worn for longer than 20 minutes. Other factors that significantly affected toxic chemical exposure and accumulation included sex (lower for males; P<0.001), facial sebum content (increase in sebum reduced toxin exposure; P=0.006), and contact area of the mask on the face (less face contact reduced toxin exposure (P=0.022).(Zhou 2022)

Flatulence

Clinical data

Capsules of powdered medicinal charcoal are promoted for use in relieving the discomfort of abdominal gas and flatulence(Gennaro 1995); however, limited clinical studies have been conducted to support this concept, and 1 study in healthy volunteers and functional patients found no effect of charcoal on bloating, abdominal pain, number of flatus episodes, abdominal girth, or cumulative breath hydrogen excretion.(Di Stefano 2000)

Gout

Clinical data

The American College of Rheumatology guidelines on the management of gout (2012) state that evidence is lacking to support the use of charcoal for gout. The new guideline (2020) based on additional evidence regarding the management of gout no longer includes a statement regarding the use of charcoal.(Fitzgerald 2020, Khanna 2012)

Malignant hyperthermia

Clinical data

The Association of Anaesthetists of Great Britain and Ireland consensus guidelines for malignant hyperthermia (2020) recommend that activated charcoal filters be available at all UK hospital locations where general anesthesia is administered.(Hopkins 2021) The European Malignant Hyperthermia Group (EMHG) consensus guidelines on the perioperative management of malignant hyperthermia suspected or susceptible patients (2021) recommend that activated charcoal filters be placed on the inspiratory and expiratory limbs of the circle systems to reduce volatile anesthetic concentrations (strong recommendation; low-quality evidence).(Ruffert 2021)

Renal disease

Clinical data

Limited clinical studies report on adsorption of toxins by charcoal in patients with chronic kidney disease (CKD) and those on hemodialysis.(Liu 2018, Schulman 2006, Wang 2012) Charcoal tablets administered to stable patients on hemodialysis facilitated serum and fecal metabolomes approaching that of controls. Abnormal tricarboxylic acid cycle intermediates were partially reversed, and the oxidative stress biomarker N¹-acetyl-5-methoxykynuramine decreased significantly; however, uremic toxins were not significantly different compared to baseline.(Liu 2018)

A systematic review of clinical trials that investigated interventions to attenuate vascular calcification progression in CKD identified only one very low–quality study in which oral activated charcoal was administered. In 50 patients with stage 3 or 4 CKD enrolled in a randomized, controlled, phase 2 study, activated charcoal administered for 2 years reduced vascular calcification better than calcium carbonate but not as well as lanthanum carbonate.(Xu 2022)

Wound healing

Clinical data

Limited studies suggest accelerated healing rates using activated charcoal dressings with or without silver.(Keiheul 2010, Verdú 2004) In a study of rectal application of activated charcoal, 35.7% of patients had complete healing of chronic anal fistulas after 8 weeks.(Zawadzki 2017)

Dosing

Acute poisoning antidote: In the management of poisonings, contact a poison control center. The American Academy of Pediatrics does not recommend administration of activated charcoal in the home, especially in cases of acute poisoning in children.(AAP 2003)

Pregnancy / Lactation

Avoid use. Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

Because activated charcoal can adsorb drugs in the GI tract, it should be taken 2 hours before or 1 hour after other medications.(Gennaro 1995)

The American Academy of Pediatrics and the American Association of Poison Control Centers recommend that ipecac syrup and charcoal not be stocked at home.(AAP 2003) Simultaneous administration of charcoal and the emetic ipecac should be avoided; charcoal may adsorb the ipecac and render it ineffective.

Acetylcysteine: Activated charcoal may decrease the serum concentration of acetylcysteine. Monitor therapy. This interaction is only expected to occur with orally administered acetylcysteine.(Ekins 1987)

Amlodipine: Activated charcoal may decrease the serum concentration of amlodipine. Monitor therapy.(Laine 1997, Tanaka 2007)

Atazanavir: Activated charcoal may decrease the serum concentration of atazanavir. Monitor therapy.(Tseng 2013)

Chloroquine: Activated charcoal may decrease the serum concentration of chloroquine. Monitor therapy.(Neuvonen 1992)

Ciprofloxacin (systemic): Activated charcoal may decrease the serum concentration of ciprofloxacin (systemic). No action needed. This interaction is only expected to occur with orally administered ciprofloxacin.(Torre 1988)

Fluoxetine: Activated charcoal may decrease serum concentrations of the active metabolite(s) of fluoxetine. Activated charcoal may decrease the serum concentration of fluoxetine. Monitor therapy.(Laine 1996)

Leflunomide: Activated charcoal may decrease serum concentrations of the active metabolite(s) of leflunomide. Consider therapy modification.(Arava April 2009, Hassikou 2008, Knab 2005, Koenig 2002, Kozer 2001, Ochi 2006, Otsuka 2008, Richards 2007, Savage 2006, Takeishi 2005, Toyokawa 2007)

Moxifloxacin (systemic): Activated charcoal may decrease the serum concentration of moxifloxacin (systemic). Monitor therapy. This interaction is likely of greater significance when moxifloxacin is administered orally.(Stass 2005)

Phenobarbital: Activated charcoal may decrease the serum concentration of phenobarbital. Monitor therapy. This interaction is likely of greater clinical significance with orally administered phenobarbital.(Tanaka 2004)

Propranolol: Activated charcoal may diminish the therapeutic effect of propranolol. Monitor therapy. This interaction is only expected to occur with orally administered propranolol.(Sood 1999)

Rifampin: Activated charcoal may decrease the absorption of rifampin. Monitor therapy. This interaction is only expected to occur with orally administered rifampin.(Orisakwe 1996)

Teriflunomide: Activated charcoal may decrease the serum concentration of teriflunomide. Consider therapy modification.(Arava April 2009, Aubagio September 2012)

Unithiol: Activated charcoal may diminish the therapeutic effect of unithiol. Avoid combination. This interaction is only applicable to orally administered unithiol.(Dimaval June 2020)

Valproate products: Activated charcoal may decrease the serum concentration of valproate products. No action needed. This interaction is only expected to occur with orally administered valproate products.(al-Shareef 1997)

Adverse Reactions