This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.
Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
When these two medicines are taken together, your body may process theophylline more quickly.
What might happen:
The blood level of your theophylline may decrease, so it may not work as well.
What you should do about this interaction:
Let your healthcare professionals know you are taking these medicines together. If your doctor prescribes these two medicines together, you may need your theophylline level checked to be sure you are receiving the right dose.If you have been medicines together on a regular schedule, and then the barbiturate (e.g. phenobarbital) or hydantoin (e.g. phenytoin) is stopped by your doctor, your may also need to have your theophylline level checked to make sure you are at a safe and effective dose.If you experience problems with your breathing, severe nausea/vomiting, tremors, heart palpitations or other effects, contact your doctor. It may be necessary to adjust the dose of your medicine.Your healthcare professionals (e.g. doctor or pharmacist) may already be aware of this drug interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Levy RH Thummel KE Trager WF. Metabolic Drug Interactions (textbook). Metabolic Drug Interactions 2000.
2.Piafsky KM, Sitar DS, Ogilvie RI. Effect of phenobarbital on the disposition of intravenous theophylline. Clin Pharmacol Ther 1977 Sep; 22(3):336-9.
3.Landay RA, Gonzalez MA, Taylor JC. Effect of phenobarbital on theophylline disposition. J Allergy Clin Immunol 1978 Jul;62(1):27-9.
4.Paladino JA, Blumer NA, Maddox RR. Effect of secobarbital on theophylline clearance. Ther Drug Monit 1983;5(1):135-9.
5.Saccar CL, Danish M, Ragni MC, Rocci ML Jr, Greene J, Yaffe SJ, Mansmann HC Jr. The effect of phenobarbital on theophylline disposition in children with asthma. J Allergy Clin Immunol 1985 Jun;75(6):716-9.
6.Gibson GA, Blouin RA, Bauer LA, Rapp RP, Tibbs PA. Influence of high-dose pentobarbital on theophylline pharmacokinetics: a case report. Ther Drug Monit 1985;7(2):181-4.
7.Yazdani M, Kissling GE, Tran TH, Gottschalk SK, Schuth CR. Phenobarbital increases the theophylline requirement of premature infants being treated for apnea. Am J Dis Child 1987 Jan;141(1):97-9.
8.Wilschanski M, Kaplan M. Phenobarbital increases aminophylline requirement in premature infants. Am J Dis Child 1988 Feb;142(2):122-3.
9.Dahlqvist R, Steiner E, Koike Y, von Bahr C, Lind M, Billing B. Induction of theophylline metabolism by pentobarbital. Ther Drug Monit 1989; 11(4):408-10.
10.Kandrotas RJ, Cranfield TL, Gal P, Ransom JL, Weaver RL. Effect of phenobarbital administration on theophylline clearance in premature neonates. Ther Drug Monit 1990 Mar;12(2):139-43.
11.Nicholson JP, Basile SA, Cury JD. Massive theophylline dosing in a heavy smoker receiving both phenytoin and phenobarbital. Ann Pharmacother 1992 Mar;26(3):334-6.
12.Taylor JW, Hendeles LWeinberger M, Lyon LW, Wyatt R, Riegelman S. The interaction of phenytoin and theophylline. Drug Intell Clin Pharm 1980; 14(9):638.
13.Marquis JF, Carruthers SG, Spence JD, Brownstone YS, Toogood JH. Phenytoin-theophylline interaction. N Engl J Med 1982 Nov 4; 307(19):1189-90.
14.Sklar SJ, Wagner JC. Enhanced theophylline clearance secondary to phenytoin therapy. Drug Intell Clin Pharm 1985 Jan;19(1):34-6.
15.Miller M, Cosgriff J, Kwong T, Morken DA. Influence of phenytoin on theophylline clearance. Clin Pharmacol Ther 1984 May;35(5):666-9.
16.Crowley JJ, Cusack BJ, Jue SG, Koup JR, Park BK, Vestal RE. Aging and drug interactions. II. Effect of phenytoin and smoking on the oxidation of theophylline and cortisol in healthy men. J Pharmacol Exp Ther 1988 May;245(2):513-23.
17.Adebayo GI. Interaction between phenytoin and theophylline in healthy volunteers. Clin Exp Pharmacol Physiol 1988 Nov;15(11):883-7.
18.Landsberg K, Shalansky S. Interaction between phenytoin and theophylline. Can J Hosp Pharm 1988 Feb;41(1):31-2.