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Drug Interactions between butabarbital / hyoscyamine / phenazopyridine and tasimelteon

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

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Interactions between your drugs

Moderate

butabarbital tasimelteon

Applies to: butabarbital / hyoscyamine / phenazopyridine and tasimelteon

MONITOR: Coadministration with inducers of CYP450 1A2 and/or 3A4 may decrease the plasma concentrations of tasimelteon, which is primarily metabolized by these isoenzymes. When tasimelteon was administered after 11 days of treatment with the potent CYP450 inducer rifampin 600 mg/day, tasimelteon systemic exposure (AUC) decreased by approximately 90% compared to tasimelteon administered alone. No data are available for use with other, less potent inducers.

MANAGEMENT: The potential for diminished therapeutic effects of tasimelteon should be considered during coadministration with inducers of CYP450 1A2 and/or 3A4. Alternative treatments may be required if an interaction is suspected.

References

  1. "Product Information. Hetlioz (tasimelteon)." Vanda Pharmaceuticals Inc (2014):

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Drug and food interactions

Major

butabarbital food

Applies to: butabarbital / hyoscyamine / phenazopyridine

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

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

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Moderate

tasimelteon food

Applies to: tasimelteon

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of tasimelteon. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

ADJUST DOSING INTERVAL: Food may delay the absorption and onset of action of tasimelteon. According to the product labeling, administration of tasimelteon with a high-fat meal decreased peak plasma concentration (Cmax) by 44% and delayed the median time to reach Cmax by approximately 1.75 hours compared to administration in the fasted state.

MONITOR: Smoking induces CYP450 1A2 and may reduce the plasma concentrations of tasimelteon, which is metabolized by the isoenzyme. According to the product labeling, tasimelteon systemic exposure was approximately 40% lower in smokers than in nonsmokers.

MANAGEMENT: Patients receiving tasimelteon should be advised to avoid or limit consumption of alcohol. Tasimelteon should be taken without food. Patients who smoke may have a reduced therapeutic response to tasimelteon.

References

  1. "Product Information. Hetlioz (tasimelteon)." Vanda Pharmaceuticals Inc (2014):

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Moderate

hyoscyamine food

Applies to: butabarbital / hyoscyamine / phenazopyridine

GENERALLY AVOID: Use of anticholinergic agents with alcohol may result in sufficient impairment of attention so as to render driving and operating machinery more hazardous. In addition, the potential for abuse may be increased with the combination. The mechanism of interaction is not established but may involve additive depressant effects on the central nervous system. No effect of oral propantheline or atropine on blood alcohol levels was observed in healthy volunteers when administered before ingestion of a standard ethanol load. However, one study found impairment of attention in subjects given atropine 0.5 mg or glycopyrrolate 1 mg in combination with alcohol.

MANAGEMENT: Alcohol should generally be avoided during therapy with anticholinergic agents. Patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them.

References

  1. Linnoila M "Drug effects on psychomotor skills related to driving: interaction of atropine, glycopyrrhonium and alcohol." Eur J Clin Pharmacol 6 (1973): 107-12

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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

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