Skip to main content

Drug Interactions between delavirdine and dyphylline / ephedrine / guaifenesin / phenobarbital

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

Edit list (add/remove drugs)

Interactions between your drugs

Major

PHENobarbital delavirdine

Applies to: dyphylline / ephedrine / guaifenesin / phenobarbital and delavirdine

GENERALLY AVOID: Coadministration with potent inducers of CYP450 3A4 may significantly decrease the plasma concentrations of delavirdine, which is primarily metabolized by the isoenzyme. In seven HIV-infected subjects, administration of delavirdine (400 mg three times a day for 30 days) in combination with the potent CYP450 3A4 inducer rifampin (600 mg once daily on days 16 thru 30) decreased mean delavirdine peak plasma concentration (Cmax), systemic exposure (AUC) and trough plasma concentration (Cmin) by approximately 92%, 97% and 100%, respectively, compared to administration of delavirdine alone. Oral clearance of delavirdine also increased by nearly 27-fold in the presence of rifampin. When delavirdine (400 mg three times a day for 30 days) was given with rifabutin (300 mg once daily on days 16 thru 30) in seven HIV-positive subjects, mean delavirdine Cmax, AUC and Cmin decreased by about 75%, 84% and 95%, respectively, and oral clearance increased by approximately 5-fold. Likewise, population pharmacokinetic data from efficacy studies showed that delavirdine Cmin was reduced by approximately 90% in patients (n=8) treated with various dosages of phenytoin, phenobarbital, and/or carbamazepine who were given delavirdine 300 to 400 mg three times a day.

MANAGEMENT: Given the risk of reduced viral susceptibility and resistance development associated with subtherapeutic antiretroviral drug levels, concomitant use of delavirdine with potent CYP450 3A4 inducers should generally be avoided.

References (6)
  1. Borin MT, Chambers JH, Carel BJ, Gagnon S, Freimuth WW (1997) "Pharmacokinetic study of the interaction between rifampin and delavirdine mesylate." Clin Pharmacol Ther, 61, p. 544-53
  2. (2001) "Product Information. Rescriptor (delavirdine)." Pharmacia and Upjohn
  3. Borin MT, Chambers JH, Carel BJ, Freimuth WW, Aksentijevich S, Piergies AA (1997) "Pharmacokinetic study of the interaction between rifabutin and delavirdine mesylate in HIV-1 infected patients." Antiviral Res, 35, p. 53-63
  4. Burman WJ, Jones BE (2001) "Treatment of HIV-related tuberculosis in the era of effective antiretroviral therapy." Am J Respir Crit Care Med, 164, p. 7-12
  5. Tran JQ, Gerber JG, Kerr BM (2001) "Delavirdine: clinical pharmacokinetics and drug interactions." Clin Pharmacokinet, 40, p. 207-26
  6. (2000) "Notice to readers: updated guidelines for the use of rifabutin or rifampin for the treatment and prevention of tuberculosis among HIV-infected patients taking protease inhibitors or nonnucleoside reverse transcriptase inhibiotrs." MMWR Morb Mortal Wkly Rep, 49, p. 185-9
Minor

ePHEDrine dyphylline

Applies to: dyphylline / ephedrine / guaifenesin / phenobarbital and dyphylline / ephedrine / guaifenesin / phenobarbital

Ephedrine-methylxanthine combinations are used for the treatment of asthma but the efficacy of the combination has been questioned. This combination may lead to increased xanthine side effects. The mechanism is unknown, but may be related to synergistic pharmacologic effects. Patients using this combination should be closely monitored for side effects such as nausea, vomiting, tachycardia, nervousness, or insomnia. If side effects are noted, the dosage of the xanthine may need to be decreased.

References (5)
  1. Weinberger M, Bronsky E, Bensch GW, Bock GN, Yecies JJ (1975) "Interaction of ephedrine and theophylline." Clin Pharmacol Ther, 17, p. 585-92
  2. Sims JA, doPico GA, Reed CE (1978) "Bronchodilating effect of oral theophylline-ephedrine combination." J Allergy Clin Immunol, 62, p. 15-21
  3. Tinkelman DG, Avner SE (1977) "Ephedrine therapy in asthmatic children. Clinical tolerance and absence of side effects." JAMA, 237, p. 553-7
  4. Weinberger MM, Brousky EA (1974) "Evaluation of oral bronchodilator therapy in asthmatic children: bronchodilators in asthmatic children." J Pediatr, 84, p. 421-7
  5. Badiei B, Faciane J, Sly M (1975) "Effect of throphylline, ephedrine and theri combination upon exercise-induced airway obstruction." Ann Allergy, 35, p. 32-6

Drug and food interactions

Major

PHENobarbital food

Applies to: dyphylline / ephedrine / guaifenesin / phenobarbital

GENERALLY AVOID: Concurrent acute use of barbiturates and ethanol may result in additive CNS effects, including impaired coordination, sedation, and death. Tolerance of these agents may occur with chronic use. The mechanism is related to inhibition of microsomal enzymes acutely and induction of hepatic microsomal enzymes chronically.

MANAGEMENT: The combination of ethanol and barbiturates should be avoided.

References (5)
  1. Gupta RC, Kofoed J (1966) "Toxological statistics for barbiturates, other sedatives, and tranquilizers in Ontario: a 10-year survey." Can Med Assoc J, 94, p. 863-5
  2. Misra PS, Lefevre A, Ishii H, Rubin E, Lieber CS (1971) "Increase of ethanol, meprobamate and pentobarbital metabolism after chronic ethanol administration in man and in rats." Am J Med, 51, p. 346-51
  3. Saario I, Linnoila M (1976) "Effect of subacute treatment with hypnotics, alone or in combination with alcohol, on psychomotor skills related to driving." Acta Pharmacol Toxicol (Copenh), 38, p. 382-92
  4. Stead AH, Moffat AC (1983) "Quantification of the interaction between barbiturates and alcohol and interpretation of fatal blood concentrations." Hum Toxicol, 2, p. 5-14
  5. Seixas FA (1979) "Drug/alcohol interactions: avert potential dangers." Geriatrics, 34, p. 89-102
Moderate

ePHEDrine food

Applies to: dyphylline / ephedrine / guaifenesin / phenobarbital

MONITOR: Coadministration of two or more sympathomimetic agents may increase the risk of adverse effects such as nervousness, irritability, and increased heart rate. Central nervous system (CNS) stimulants, particularly amphetamines, can potentiate the adrenergic response to vasopressors and other sympathomimetic agents. Additive increases in blood pressure and heart rate may occur due to enhanced peripheral sympathetic activity.

MANAGEMENT: Caution is advised if two or more sympathomimetic agents are coadministered. Pulse and blood pressure should be closely monitored.

References (7)
  1. Rosenblatt JE, Lake CR, van Kammen DP, Ziegler MG, Bunney WE Jr (1979) "Interactions of amphetamine, pimozide, and lithium on plasma norepineophrine and dopamine-beta-hydroxylase in schizophrenic patients." Psychiatry Res, 1, p. 45-52
  2. Cavanaugh JH, Griffith JD, Oates JA (1970) "Effect of amphetamine on the pressor response to tyramine: formation of p-hydroxynorephedrine from amphetamine in man." Clin Pharmacol Ther, 11, p. 656
  3. (2001) "Product Information. Adderall (amphetamine-dextroamphetamine)." Shire Richwood Pharmaceutical Company Inc
  4. (2001) "Product Information. Tenuate (diethylpropion)." Aventis Pharmaceuticals
  5. (2001) "Product Information. Sanorex (mazindol)." Novartis Pharmaceuticals
  6. (2001) "Product Information. Focalin (dexmethylphenidate)." Mikart Inc
  7. (2002) "Product Information. Strattera (atomoxetine)." Lilly, Eli and Company

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.

See also

Report options

Loading...
QR code containing a link to this page

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

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer