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Drug Interactions between Avonex Prefilled Syringe and Truxophyllin

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

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Interactions between your drugs

Moderate

theophylline interferon beta-1a

Applies to: Truxophyllin (theophylline) and Avonex Prefilled Syringe (interferon beta-1a)

MONITOR: The coadministration with interferons has been associated with decreases in clearance and increases in plasma concentration and elimination half-life of theophylline. The mechanism is unknown but may be related to interferon-induced suppression of hepatic CYP450 enzymes, particularly, CYP450 1A2. Physiologic events and drugs that induce interferon synthesis (e.g., viral infection, influenza vaccination) have also been reported to decrease metabolism and potentiate the effects of certain drugs including theophylline. Some authorities suggest that the interaction with peginterferon alfa-2a may be maximal after more than 4 weeks of concomitant therapy.

MANAGEMENT: Caution is advised if theophylline or other methylxanthines are administered with an interferon. Pharmacologic response and serum theophylline levels should be monitored and the dosage adjusted accordingly, particularly following initiation or discontinuation of interferon therapy in patients who are stabilized on their methylxanthine regimen. Patients should be advised to contact their physician if they experience signs and symptoms of theophylline toxicity such as nausea, vomiting, diarrhea, headache, restlessness, insomnia, or irregular heartbeat.

References

  1. Kramer P, Tsuru M, Cook CE, et al. "Effect of influenza vaccine on warfarin anticoagulation." Clin Pharmacol Ther 35 (1984): 416-8
  2. Upton RA "Pharmacokinetic interactions between theophylline and other medication (Part II)." Clin Pharmacokinet 20 (1991): 135-50
  3. Williams SJ, Baird-Lambert JA, Farrell GC "Inhibition of theophylline metabolism by interferon." Lancet 10/24/87 (1987): 939-41
  4. Jonkman JH, Nicholson KG, Farrow PR, et al. "Effects of alpha-interferon on theophylline pharmacokinetics and metabolism." Br J Clin Pharmacol 27 (1989): 795-802
  5. Okuno H, Takasu M, Kano H, Seki T, Shiozaki Y, Inoue K "Depression of drug-metabolizing activity in the human liver by interferon-beta." Hepatology 17 (1993): 65-9
  6. "Product Information. Intron A (interferon alfa-2b)." Schering Corporation PROD (2001):
  7. Sakai H, Okamoto T, Kikkawa Y "Suppression of hepatic drug metabolism by the interferon inducer polyriboinosinic acid:polyribocitidylic acid." J Pharmacol Exp Ther 263 (1992): 381-6
  8. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  9. Cerner Multum, Inc. "Australian Product Information." O 0
View all 9 references

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Drug and food interactions

Moderate

theophylline food

Applies to: Truxophyllin (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: Truxophyllin (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.

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