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Drug Interactions between aminophylline / ephedrine / guaifenesin / phenobarbital and mifepristone

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

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Interactions between your drugs

Moderate

PHENobarbital aminophylline

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

MONITOR: Barbiturates may decrease serum levels and therapeutic effects of the methylxanthines. The mechanism is barbiturate induction of CYP450 3A4 and 1A2 hepatic metabolism of methylxanthines.

MANAGEMENT: Close observation for clinical and laboratory evidence of decreased methylxanthine effect is indicated if these drugs must be used together. Patients should be advised to notify their physician if they experience a worsening of their respiratory symptoms.

References (4)
  1. Upton RA (1991) "Pharmacokinetic interactions between theophylline and other medication (Part I)." Clin Pharmacokinet, 20, p. 66-80
  2. Bukowskyj M, Nakatsu K, Munt PW (1984) "Theophylline reassessed." Ann Intern Med, 101, p. 63-73
  3. Landay RA, Gonzalez MA, Taylor JC (1978) "Effect of phenobarbital on theophylline disposition." J Allergy Clin Immunol, 62, p. 27-9
  4. Dahlqvist R, Steiner E, Koike Y, von Bahr C, Lind M, Billing B (1989) "Induction of theophylline metabolism by pentobarbital." Ther Drug Monit, 11, p. 408-10
Moderate

PHENobarbital miFEPRIStone

Applies to: aminophylline / ephedrine / guaifenesin / phenobarbital and mifepristone

GENERALLY AVOID: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of mifepristone, which is primarily metabolized by the isoenzyme. However, the interaction has not been studied, and the clinical impact is unknown.

MANAGEMENT: When mifepristone is prescribed daily to control hyperglycemia secondary to hypercortisolism in patients with endogenous Cushing's syndrome, concomitant use with potent CYP450 3A4 inducers such as carbamazepine, phenobarbital, phenytoin, and rifamycins should generally be avoided. Other, less potent inducers such as aminoglutethimide, barbiturates, bexarotene, bosentan, dabrafenib, efavirenz, nafcillin, nevirapine, somatrem, somatropin, and various other anticonvulsants may also interact. Caution is advised if they are used with mifepristone.

References (2)
  1. (2001) "Product Information. Mifeprex (mifepristone)." Danco Laboratories
  2. (2012) "Product Information. Korlym (mifepristone)." Corcept Therapeutics Incorporated
Minor

ePHEDrine aminophylline

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

miFEPRIStone food

Applies to: mifepristone

ADJUST DOSING INTERVAL: Food may significantly increase the plasma concentrations of mifepristone.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of mifepristone. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Because pharmacokinetic interactions involving grapefruit juice are often subject to a high degree of interpatient variability, the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: When mifepristone is used daily to control hyperglycemia secondary to hypercortisolism in patients with endogenous Cushing's syndrome, it should be taken with food to achieve consistent plasma drug levels. Patients should be advised to avoid consuming grapefruit or grapefruit juice during treatment with mifepristone, as it may cause increased adverse effects such as headache, dizziness, fatigue, nausea, vomiting, cramping, diarrhea, hypokalemia, adrenal insufficiency, vaginal bleeding, arthralgia, peripheral edema, and hypertension. Because mifepristone is eliminated slowly from the body, the interaction with grapefruit juice may be observed for a prolonged period.

References (2)
  1. (2001) "Product Information. Mifeprex (mifepristone)." Danco Laboratories
  2. (2012) "Product Information. Korlym (mifepristone)." Corcept Therapeutics Incorporated
Moderate

ePHEDrine food

Applies to: aminophylline / 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
Moderate

aminophylline food

Applies to: aminophylline / 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.

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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

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

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