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Drug Interactions between Charcoaid-G and Theo-24

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

theophylline charcoal

Applies to: Theo-24 (theophylline) and Charcoaid-G (charcoal)

GENERALLY AVOID: Charcoal may reduce the absorption of many drugs and can absorb enterohepatically circulated drugs. Clinical utility may be the reduction either of the effects or of the toxicity of many drugs. Activated charcoal may adsorb any therapeutic agents administered while it is in the gastrointestinal tract.

MANAGEMENT: The regular ingestion of charcoal should be avoided by patients requiring maintenance medications. If concomitant use is necessary, the dosage or route of administration may need to be altered.

References

  1. Decker WJ, Shpall RA, Corby DG "Inhibition of aspirin absorption by activated charcoal and apomorphine." Clin Pharmacol Ther 10 (1969): 710-3
  2. Knadler MP, Bergstrom RF, Callaghan JT, Obermeyer BD, Rubin A "Absorption studies of the H2-blocker nizatidine." Clin Pharmacol Ther 42 (1987): 514-20
  3. Wing LM, Miners JO, Birkett DJ, et al. "Lidocaine disposition: sex differences and effects of cimetidine." Clin Pharmacol Ther 35 (1984): 695-701
  4. Scheufler E, Bos I "Influence of peroral charcoal on pharmacokinetics and intestinal toxicity of intravenously given methotrexate." Arch Int Pharmacodyn Ther 261 (1983): 180-5
  5. Gadgil SD, Damle SR, Advani SH, Vaidya AB "Effect of activated charcoal on the pharmacokinetics of high-dose methotrexate." Cancer Treat Rep 66 (1982): 1169-71
  6. Park GD, Spector R, Goldberg MJ, Johnson GF "Expanded role of charcoal therapy in the poisoned and overdosed patient." Arch Intern Med 146 (1986): 969-73
  7. Watson WA "Factors influencing the clinical efficacy of activated charcoal." Drug Intell Clin Pharm 21 (1987): 160-6
  8. Kivisto KT, Neuvonen PJ "The effect of cholestyramine and activated charcoal on glipizide absorption." Br J Clin Pharmacol 30 (1990): 733-6
  9. Dolgin JG, Nix DE, Sanchez J, Watson WA "Pharmacokinetic simulation of the effect of multiple-dose activated charcoal in phenytoin poisoning: report of two pediatric cases." DICP 25 (1991): 646-9
  10. Rowden AM, Spoor JE, Bertino JS, Jr "The effect of activated charcoal on phenytoin pharmacokinetics." Ann Emerg Med 19 (1990): 1144-7
  11. Farrar HC, Herold DA, Reed MD "Acute valproic acid intoxication: enhanced drug clearance with oral-activated charcoal." Crit Care Med 21 (1993): 299-301
  12. Howard CE, Roberts RS, Ely DS, Moye RA "Use of multiple-dose activated charcoal in phenytoin toxicity." Ann Pharmacother 28 (1994): 201-3
  13. Chernish SM, Wolen RL, Rodda BE "Adsorption of propoxyphene hydrochloride by activated charcoal." Clin Toxicol 5 (1972): 317-29
  14. Glab WN, Corby DG, Decker WJ, Coldiron VR "Decreased absorption of propoxyphene by activated charcoal." J Toxicol Clin Toxicol 19 (1982): 129-38
  15. Karkkainen S, Neuvonen PJ "Effect of oral charcoal and urine pH on dextropropoxyphene pharmacokinetics." Int J Clin Pharmacol Ther Toxicol 23 (1985): 219-25
  16. Wakabayashi Y, Maruyama S, Hachimura K, Ohwada T "Activated charcoal interrupts enteroenteric circulation of phenobarbital." J Toxicol Clin Toxicol 32 (1994): 419-24
  17. Reed MD "Oral activated charcoal therapy." Am J Emerg Med 6 (1988): 318
  18. Neuvonen PJ "Clinical pharmacokinetics of oral activated charcoal in acute intoxications." Clin Pharmacokinet 7 (1982): 465-89
  19. Naveau S, Bonhomme L, Preaux N, Chaput JC "A pure charcoal suspension for colonoscopic tattoo." Gastrointest Endosc 37 (1991): 624-5
  20. Ilkhanipour K, Yealy DM, Krenzelok EP "Activated charcoal surface area and its role in multiple-dose charcoal therapy." Am J Emerg Med 11 (1993): 583-5
  21. Saetta JP "Gastric decontaminating procedures: is it time to call a stop?" J R Soc Med 86 (1993): 396-9
  22. Orisakwe OE "Activated charcoal: is failure to use it negligence or ignorance?" South Med J 87 (1994): 165-8
  23. Herrington AM, Clifton GD "Toxicology and management of acute drug ingestions in adults." Pharmacotherapy 15 (1995): 182-200
  24. Bonuccelli U, Piccini P, Del Dotto P, Pavese N, D'Antonio P, Muratorio A "Apomorphine test in de novo Parkinson's disease." Funct Neurol 7 (1992): 295-8
  25. "Product Information. Trileptal (oxcarbazepine)." Novartis Pharmaceuticals PROD (2001):
View all 25 references

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Drug and food interactions

Moderate

theophylline food

Applies to: Theo-24 (theophylline)

GENERALLY AVOID: Coadministration with caffeine may increase the serum concentrations of theophylline. The proposed mechanism involves competitive inhibition of theophylline metabolism via CYP450 1A2, as well as metabolic conversion of caffeine to theophylline in vivo and saturation of theophylline metabolism at higher serum concentrations. In six healthy male volunteers (all smokers), serum concentrations of theophylline (administered as aminophylline 400 mg single oral dose) were significantly higher following consumption of caffeine (2 to 7 cups of instant coffee over 24 hours, equivalent to approximately 120 to 630 mg of caffeine) than after caffeine deprivation for 48 hours. Caffeine consumption also increased the apparent elimination half-life of theophylline by an average of 32% and reduced its total body clearance by 23%. In another study, steady-state concentration and area under the concentration-time curve of theophylline (1200 mg intravenously over 24 hours) increased by 23% and 40%, respectively, in eight healthy volunteers following administration of caffeine (300 mg orally three times a day).

MANAGEMENT: Given the narrow therapeutic index of theophylline, patients should limit or avoid significant fluctuations in their intake of pharmacologic as well as dietary caffeine.

ADJUST DOSING INTERVAL: Administration of theophylline with continuous enteral nutrition may reduce the serum levels or the rate of absorption of theophylline. The mechanism has not been reported. In one case, theophylline levels decreased by 53% in a patient receiving continuous nasogastric tube feedings and occurred with both theophylline tablet and liquid formulations, but not with intravenous aminophylline.

MANAGEMENT: When administered to patients receiving continuous enteral nutrition , some experts recommend that the tube feeding should be interrupted for at least 1 hour before and 1 hour after the dose of theophylline is given; rapid-release formulations are preferable, and theophylline levels should be monitored.

References

  1. Jonkman JH, Sollie FA, Sauter R, Steinijans VW "The influence of caffeine on the steady-state pharmacokinetics of theophylline." Clin Pharmacol Ther 49 (1991): 248-55
  2. Sato J, Nakata H, Owada E, Kikuta T, Umetsu M, Ito K "Influence of usual intake of dietary caffeine on single-dose kinetics of theophylline in healthy human subjects." Eur J Clin Pharmacol 44 (1993): 295-8
  3. Wohlt PD, Zheng L, Gunderson S, Balzar SA, Johnson BD, Fish JT "Recommendations for the use of medications with continuous enteral nutrition." Am J Health Syst Pharm 66 (2009): 1438-67

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Moderate

theophylline food

Applies to: Theo-24 (theophylline)

GENERALLY AVOID: Coadministration with caffeine may increase the serum concentrations of theophylline. The proposed mechanism involves competitive inhibition of theophylline metabolism via CYP450 1A2, as well as metabolic conversion of caffeine to theophylline in vivo and saturation of theophylline metabolism at higher serum concentrations. In six healthy male volunteers (all smokers), serum concentrations of theophylline (administered as aminophylline 400 mg single oral dose) were significantly higher following consumption of caffeine (2 to 7 cups of instant coffee over 24 hours, equivalent to approximately 120 to 630 mg of caffeine) than after caffeine deprivation for 48 hours. Caffeine consumption also increased the apparent elimination half-life of theophylline by an average of 32% and reduced its total body clearance by 23%. In another study, steady-state concentration and area under the concentration-time curve of theophylline (1200 mg intravenously over 24 hours) increased by 23% and 40%, respectively, in eight healthy volunteers following administration of caffeine (300 mg orally three times a day).

MANAGEMENT: Given the narrow therapeutic index of theophylline, patients should limit or avoid significant fluctuations in their intake of pharmacologic as well as dietary caffeine.

References

  1. Jonkman JH, Sollie FA, Sauter R, Steinijans VW "The influence of caffeine on the steady-state pharmacokinetics of theophylline." Clin Pharmacol Ther 49 (1991): 248-55
  2. Sato J, Nakata H, Owada E, Kikuta T, Umetsu M, Ito K "Influence of usual intake of dietary caffeine on single-dose kinetics of theophylline in healthy human subjects." Eur J Clin Pharmacol 44 (1993): 295-8

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Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

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