Activated charcoal is a type of amorphous carbon prepared by destructive distillation of such materials as wood, vegetables and coconut shells, materials that have much higher surface areas than charcoal itself. It is a fine, black powder of largely pure carbon. The large surface area of activated charcoal confers a great adsorptive capacity to this material. It is this great adsorptive capacity that is the basis for its many industrial as well as medical uses. There are different types of activated charcoal with different adsorption characteristics. The adsorptive characteristics are determined by the configuration of the surface of activated charcoal.
Activated charcoal is widely used in the treatment of acute poisoning (overdose) with such substances as acetaminophen, salicylates, barbiturates and tricyclic antidepressants. Activated charcoal strongly adsorbs aromatic substances such as the above, reducing their absorption from the gastrointestinal tract. Most inorganic poisons are not significantly adsorbed by activated charcoal. A major industrial use of activated charcoal is as a decolorizer. For example, it is used in the late stages of sugar refining to produce white sugar. Activated charcoal is commonly used in air and water filters.
Activated charcoal, in addition to some other substances, has been used in Russia for the treatment of a number of disorders and diseases, including hyperlipidemia, liver, biliary tract and renal diseases. The practice is known as enterosorption and carbon sorption therapy, when activated charcoal is the principle therapeutic component. Oral activated charcoal is known to lower cholesterol levels.
Activated charcoal is also known as active carbon, activated carbon, adsorbent charcoal, carbo activatus, carbo medicinalis, carbon active, carbon attivo, decolorizing charcoal, activkohle (German) and medicinal charcoal.
Actions & Pharmacology
Activated charcoal is a gastrointestinal adsorbent. It may also have hypocholesterolemic activity.
Mechanism of Action
The large surface area of activated charcoal confers a great adsorptive capacity to this material. The adsorptive capacity of this substance differs for various chemical entities. Activated charcoal is most effective in adsorbing aromatic or benzenoid-type substances. Less well adsorbed are non-aromatic (non-benzenoid) substances, such as the various fatty acids and fatty alcohols. Inorganic substances are poorly adsorbed by activated charcoal. Aromatic substances, such as acetaminophen, salicylates, barbiturates and tricyclic antidepressants, are very strongly adsorbed by activated charcoal, and that is why activated charcoal is commonly used in the management of overdosage of these substances. Adsorption of these drugs reduces their absorption from the gastrointestinal tract.
The mechanism of the hypocholesterolemic effect of activated charcoal is not entirely clear. It is thought that the cholesterol-lowering effect of activated charcoal is caused by its interference with the enterohepatic circulation of bile acids.
Activated charcoal is not absorbed via the gastrointestinal tract, and all ingested activated charcoal is excreted in the feces.
Indications & Usage
Results have been mixed in studies using charcoal in patients with gas complaints. There is some evidence that activated charcoal can favorably affect lipids and that it might be helpful in alleviating symptoms associated with cholestasis of pregnancy. Activated charcoal looks promising for the treatment of uremic pruritis, as well as for congenital erythropoietic porphyria.
Those who use activated charcoal as an antflatulant typically use 500 to 1000 milligrams as needed. Those who use activated charcoal for its possible cholesterol-lowering effect take 5 to 8 grams two to three times daily. Those who use activated charcoal combine it with plenty of water and must not use it within two hours before or after ingesting any drug, food, nutritional supplement or herb.
LiteratureFriedman EA, Saltzman MJ, Delano BG, Bayer MM. Reduction in hyperlipidemia in hemodialysis patients treated with charcoal and oxidized starch (oxystarch). Am J Clin Nutr. 1978; 31:1903-1914.Giovannetti S, Barsotti G, Cupisti A, et al. Oral activated charcoal in patients with uremic pruritis. Nephron. 1995; 70:193-196.Kaaja RJ, Kontula KK, Raiho A, Laatikainen T. Treatment of cholestasis of pregnancy with peroral activated charcoal. A preliminary study. Scand J Gastroenterol. 1994; 29:178-181.Korkushko OV, Bogatskaia LN, Novikova SN, et al. [Use of enterosorption for correction of dyslipoproteinemias in patients with ischemic heart disease in geriatric patients]. [Article in Russian]. Klin Med (Mosk). 1991; 69:51-53.Kuusisto P, Vapaatalo H, Manninen V, et al. Effect of activated charcoal on hypercholesterolaemia. Lancet. 1986; 2(8503):366-367.Neuvonen PJ, Kuusisto P, Manninen V, et al. The mechanism of the hypocholesterolaemic effect of activated charcoal. Eur J Clin Invest. 1989; 19:251-254.Neuvonen PJ, Kuusisto P, Vapaatalo H, Manninen V. Activated charcoal in the treatment of hypercholesterolaemia: dose-response relationships and comparison with cholestyramine. Eur J Clin Pharmacol. 1989; 37:225-230Nikolaev VG. Peroral application of synthetic activated charcoal in USSR. Biomater Artif Cells Artif Organs. 1990; 18:555-568.Pimstone NR, Gandhi SN, Mukerji SK. Therapeutic efficacy of oral charcoal in congenital erythropoietic porphyria. N Engl J Med. 1987; 316:390-393.Robertson KE, Mueller BA. Uremic pruritis. Am J Health Syst Pharm. 1996; 53:2159-2170.Suarez FL, Furne J. Springfield J, Levitt MD. Failure of activated charcoal to reduce the release of gases produced by the colonic flora. Am J Gastroenterol. 1999; 94:208-212.Windrum P, Hull DR, Morris TCM. Herb-drug interactions. Lancet. 2000; 355:1019-1020.
Research & Summary
There are inconsistent results in studies related to activated charcoal's efficacy in reducing intestinal gas and symptoms related thereto. In one double-blind study, the substance significantly reduced bloating and abdominal cramps associated with gaseousness. Some other studies have confirmed this effect, and some others have not, discrepancies that may be related to dosing and sampled populations. One researcher reported that activated charcoal effectively adsorbs intestinal gas in healthy subjects but that it ""has not been properly investigated in patients with gas complaints.''
Oral activated charcoal has significantly lowered plasma total cholesterol and LDL-cholesterol in both animals and humans. It has also raised HDL-cholesterol in some studies. In one crossover study of seven subjects ingesting 4, 8, 16 or 32 grams per day of activated charcoal, serum total and LDL-cholesterol were decreased (maximum 29% and 41% respectively) and the ratio of HDL/LDL-cholesterol was increased (maximum 121%) by activated charcoal in a dose-dependent pattern.
Ten additional subjects with severe hypercholesterolemia took daily, in random order, for three weeks, 16 grams of activated charcoal, 16 grams of cholestyramine or 8 grams of activated charcoal plus 8 grams of cholestyramine. Activated charcoal reduced total and LDL-cholesterol concentrations 23% and 29%, respectively; cholestyramine reduced them 32% and 39%; in combination, they reduced them 30% and 38%. The ratio of HDL/LDL-cholesterol increased from 0.13 to 0.23 with activated charcoal, to 0.29 with cholestyramine and to 0.25 with the combination. Cholestyramine increased serum triglycerides, but activated charcoal did not. Research is ongoing.
Given that elevated serum bile acid levels are thought to play a role in cholestasis of pregnancy, activated charcoal was administered to women with this condition to see if it could decrease these levels. The women were given 50 grams of the substance three times a day for eight days. By day eight, serum total bile acid concentrations were significantly reduced. Outcome of pregnancy was good. This preliminary study needs followup to see whether activated charcoal might be an option in the treatment of entrahepatic cholestasis of pregnancy.
Activated charcoal given as an oral dose of 6 grams provided symptomatic relief in nearly 50% of patients with uremic pruritis, a poorly understood symptom of uremia. The studies have, however, been limited. More research is needed.
Finally, activated charcoal was more effective in reducing plasma porphyrin levels than oral cholestyramine in a patient with congenital erythropoietic porphyria or Gunther's disease. Again, more research is needed.
Contraindications, Precautions & Adverse Reactions
Activated charcoal is contraindicated in those whose gastrointestinal tract is not anatomically intact.
Activated charcoal adsorbs a wide range of drugs and nutrients. Those using activated charcoal should avoid using it within two hours of drug, food, nutritional supplement or herb intake or within two hours before their intake.
Black stools (from the activated charcoal) occur frequently. Other reported adverse reactions include nausea, vomiting, blackening of the teeth and mouth, abdominal discomfort, diarrhea (more frequent) and constipation (less frequent).
There are occasional reports of drug failure in those who use activated charcoal concomitantly with a drug.
Activated charcoal adsorbs a wide range of drugs and nutrients. Therefore, those using activated charcoal should avoid using it within two hours of drug, food, nutritional supplement or herb intake or within two hours before their intake.