Wood charcoal
The properties are similar to activated charcoal, so click to activated charcoal for the details.
Activated Charcoal
A fine, light, odourless, tasteless, black powder, free from grittiness. The Ph. Eur, describes material prepared from vegetable matter by carbonisation processes intended to confer a high adsorbing power. The USP describes the residue from the destructive distillation of various organic materials, treated to increase its adsorptive power.
The Ph. Eur. Specifies that it adsorbs not less than 40% of its own weight of phenazone, calculated with reference to the dried substance. The USP has tests for adsorptive power in respect of alkaloids and dyes. Practically insoluble in all usual solvents. Store in airtight containers.
Adverse Effects and Precautions
Activated charcoal is relatively non - toxic when given by mouth but gastro - intestinal disturbances such as vomiting, constipation, or diarrhoea have been reported. It may colour the faeces black.
Haemoperfusion with activated charcoal has produced various adverse effects including platelet aggregation, charcoal embolism, thrombocytopenia, haemorrhage, hypoglycaemia, hypocalcaemia, hypothermia, and hypotension.
Activated charcoal in contra - indicated when specific oral antidotes such as methionine are used (see Interactions, below).
Effects on the gastro - intestinal tract. Intestinal obstruction or faecal impaction, in one case resulting in rectal ulceration, has been reported following multiple oral doses of activated charcoal. Special care should be taken when treating overdoses of drugs with antimuscarinic activity, such as tricyclic antidepressants and phenothiazines. Two cases of pseudo - obstruction, one of which was fatal, have also been reported following the use of activated charcoal and sorbitol with opioid sedation for theophylline poisoning. Care should also be taken to prevent pulmonary aspiration (see below).
Effects on the lungs. Pulmonary aspiration of activated charcoal, sometimes with fatal results, has been reported following oral administration for the treatment of acute poisoning. Vomiting has been reported to be fairly common by some, but not all, correspondents following activated charcoal administration ; the water load resulting from repeated administration of charcoal slurry could contribute to the nausea and vomiting encountered and the use of sorbitol containing preparations has also been said to contribute to the vomiting. The use of a cuffed endotracheal tube has been recommended for any patients impaired laryngeal reflexes to prevent aspiration.
Interactions
Activated charcoal diminishes the action of ipecacuanha and other emetics when given concomitantly by mouth ; if indicated, emesis should be induced before activated charcoal is administered. Activated charcoal has the potential to reduce the absorption of many drugs from the gastro - intestinal tract and simultaneous oral therapy should therefore be avoided. In the management of acute poisoning, concurrent medication should be administered parenterally. Activated charcoal should not be administered when a specific oral antidote such as methionine is used since adsorption of the antidote may decrease its effectiveness.
Uses and Administration
Activated charcoal can adsorb a wide range of plant and inorganic poisons and many drugs including salicylates, paracetamol, barbiturates, and tricyclic antidepressants ; thus when administered by mouth it reduces their systemic absorption from the gastro - intestinal tract and is used in the treatment of acute oral poisoning. It is of no value in the treatment of poisoning by strong acids, alkalis, or other corrosive substances and its adsorptive capacity is too low to be of use in poisoning with iron salts, cyanides, lithium, malathion, dicophane, and some organic solvents such as methyl alcohol or ethylene glycol. Adsorption characteristics can be influenced by charcoal's particle size, thus different responses may be obtained with different preparations.
Activated charcoal is given by mouth usually as a slurry in water. The usual dose is 50 gm, but higher doses have been used. For maximum efficacy, activated charcoal should be administered as soon as possible after ingestion of the toxic compound. However, it may be effective several hours after poisoning with certain drugs that slow gastric emptying. In the case of drugs that undergo enterohepatic or enteroenteric recycling (e.g. phenobarbitone and theophylline) repeated doses of activated charcoal are of value in enhancing faecal elimination. Doses for repeated administration have varied but typically 50 gm may be given every 4 hours or 25 gm every 2 hours. Administration may also be via a nasogastric tube.
Mixtures such as 'universal antidote' that contained activated charcoal, magnesium oxide, and tannic acid should not be used ; activated charcoal alone is more effective and tannic acid may cause hepatotoxicity.
In the charcoal haemoperfusion treatment of poisoning, activated charcoal may be used to remove drugs from the blood stream. It may be of value in acute severe poisoning by drugs such as the barbiturates, glutethimide, or theophylline when other intensive measures fail to improve the condition of the patient.
Activated charcoal is used in dressings for ulcers and suppurating wounds to reduce malodour and may improve the rate of healing.
Activated charcoal has been used as a marker of intestinal transit and has also been tried in the treatment of flatulence. Both activated charcoal and vegetable charcoal (wood charcoal) are included in preparations for various gastro-intestinal disorders.
Technical grades of activated charcoal have been used as purifying and decolorising agents, for the removal of residual gases in low-pressure apparatus, and in respirators as a protection against toxic gases.
Administration. Activated charcoal is most commonly administered as a slurry in water but this is often found to be unpalatable because of the colour, gritty taste, lack of flavour, and difficulty in swallowing. Efforts have therefore been made to improve its palatability but studies in vitro or in healthy subjects have indicated that some foods such as ice cream, milk and cocoa might inhibit the adsorptive capacity of activated charcoal whereas starches and jams appeared to have no effect. Carmellose has been demonstrated to improve palatability though it might also reduce the adsorptive power of activated charcoal. Scholtz et al. Found that activated charcoal formulations containing sorbitol, carmellose sodium, or starch were more palatable and essentially equivalent to the aqueous slurry formulation in efficacy. When chocolate syrup was used as a sweet flavouring agent it had to be added just before administration as the sweetiness and flavour disappeared after a few minutes contact with the activated charcoal. Results of a study by Cooney also suggested that saccharin sodium, sucrose, or sorbitol might be suitable flavouring agents for activated charcoal formulations. A survey by Mcfarland and Chyka of commercially available ready - to - use charcoal preparations in the USA indicated that although differences did exist between the formulations, the clinical significance of such variations was unknown. They highlighted the problems associated with sorbitol-containing products (see also
Under Poisoning, below) and cautioned against their use, especially for repeated - dose therapy.
Poisoning. The administration of a single oral dose of activated charcoal has become a widespread method of preventing the absorption of ingested compounds and may be superior to gastric emptying. In addition, multiple oral doses of activated charcoal have been found to enhance the elimination of some drugs and toxic substances even after systemic absorption. Mechanisms by which activated charcoal may increase drug elimination from the body include interruption of the enterohepatic circulation of drugs excreted into the bile, reduction of the reabsorption of drugs which diffuse or are actively secreted into the intestines, and increased elimination of the drug via the gastro - intestinal tract when co - administered with a laxative to decrease gastro - intestinal transit time, although the practice of giving charcoal with a laxative has been questioned. Repeated oral doses of activated charcoal may therefore be considered for compounds that undergo enterohepatic or enteroenteric circulation, have a small volume of distribution, are not extensively bound to plasma proteins, and have a low endogenous clearance. Anecdotal reports and studies in acutely poisoned patients indicate that a technique of giving multiple doses of charcoal may offer an alternative to charcoal haemoperfusion or haemodialysis. However, while activated charcoal is generally well tolerated, major complications do occasionally occur, including pulmonary aspiration and bowel obstruction. Also, use of multiple doses of charcoal preparations containing sorbitol or sodium bicarbonate can result in increased vomiting or in electrolyte disturbances. Thus some have questioned the rose of multiple dose therapy.
HAEMOPERFUSION : - Haemoperfusion involves the passage of blood through an adsorbent material such as activated charcoal or synthetic hydrophobic polystyrene resins which can retain certain drugs and toxic agents. Early problems with charcoal haemoperfusion such as charcoal embolism, marked thrombocytopenia. Fibrinogen loss, and pytogen reactions have been largely overcome by purification procedures and by coating the carbon with biocompatible polymers. However, transient falls in platelet count, leucocyte count, and circulatory concentrations of clotting factors, calcium, glucose, urea, creatinine, and urate have been reported during haemoperfusion. While there is no substitute for supportive measures. Haemoperfusion can significantly reduce the body burden of certain compounds with a low volume of distribution within 4 to 6 hours in some severely poisoned patients ; haemoperfusion is not effective for drugs or poisons with very large volumes of distribution.
Porphyria : Activated charcoal may be used as part of the management of erythropoietic protoporphyria, one of the non-acute porphyrias. It acts as absorbent in the gut lumen, interrupting the enterohepatic recycling of protoporphyrin. It has also been tried in a patient with photomutilation diagonsed as having congenital erythropoitic prophyria, a very rare porphyria. Activated charcoal 30 gm given by mouth every 3 hours for 36 hours reduced the plasma - porphyrin concentration to normal values by 20 hours and was more effective than cholestyramine or transfusional therapy. After discontinuation of activated charcoal, plasmin - porphyrin concentrations rose rapidly to near pretreatment levels within 10 days. Long - term treatment with oral charcoal over a 9 month period effected a clinical remission with low concentrations of plasma and skin porphyrin and an absence of photocutaneous activity. The optimal dose was determined to be 60 gm three times a day. However, exacerbation following an initial period of remission has been reported in another patient and total lack of efficacy in a third.
Pruritus : Pruritus is usually treated symptomatically. Activated charcoal has been tried in pruritus associated with renal failure. In a double - blind corssover study, administration of activated charcoal 6 gm daily by mouth for 8 weeks was more effective than placebo in relieving generalised pruritus in 11 patients undergoing maintenance haemodialysis.
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