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Drug interactions between Flomax and Tylenol Allergy Complete NightTime

Results for the following 2 drugs:
Flomax (tamsulosin)
Tylenol Allergy Complete NightTime (acetaminophen/diphenhydramine/pseudoephedrine)

Interactions between your drugs


diphenhydramine ↔ tamsulosin

Applies to:Tylenol Allergy Complete NightTime (acetaminophen/diphenhydramine/pseudoephedrine) and Flomax (tamsulosin)

Tamsulosin and diphenhydrAMINE may have additive effects in lowering your blood pressure. You may experience headache, dizziness, lightheadedness, fainting, and/or changes in pulse or heart rate. These side effects are most likely to be seen at the beginning of treatment, following a dose increase, or when treatment is restarted after an interruption. Let your doctor know if you develop these symptoms and they do not go away after a few days or they become troublesome. Avoid driving or operating hazardous machinery until you know how the medications affect you, and use caution when getting up from a sitting or lying position. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

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pseudoephedrine ↔ tamsulosin

Applies to:Tylenol Allergy Complete NightTime (acetaminophen/diphenhydramine/pseudoephedrine) and Flomax (tamsulosin)

Consumer information for this interaction is not currently available.

MONITOR: Sympathomimetic agents, such as pseudoephedrine, may antagonize the effects of antihypertensives that interfere with sympathetic activity, such as alpha- and beta-adrenergic blocking agents. In contrast, alpha- and beta-blockers may diminish the vasoconstrictive effects of sympathomimetics. The mechanism of this interaction has not been reported, but may involve competitive inhibition at the adrenergic receptor. Severe hypertension may occur in patients receiving beta-blockers.

MANAGEMENT: Caution and close monitoring of blood pressure is recommended if pseudoephedrine is administered with these antihypertensives. Discontinuation of the sympathomimetic may be necessary if hypertension develops.


  1. Cerner Multum, Inc. "Australian Product Information." O 0
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. "Product Information. Allegra-D (fexofenadine-pseudoephedrine)." Hoechst Marion-Roussel Inc, Kansas City, MO.

Drug and food interactions


tamsulosin food

Applies to: Flomax (tamsulosin)

Food may affect the intestinal absorption of tamsulosin. You should take tamsulosin approximately one-half hour following the same meal each day to ensure steady absorption and blood levels of the drug.

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Therapeutic duplication warnings

No therapeutic duplications were found for your selected drugs.

Drug Interaction Classification

The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
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 information available.

Do not stop taking any medications without consulting your healthcare provider.

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