Singulair Drug Interactions

by on July 20, 2012

Combining Singulair with other drugs, medications or herbal products can cause certain interactions and side effects. Some drugs increase your risk for adverse effects or may cause Singulair not to work effectively. Although these drug interactions are possible, they do not happen all the time. Your healthcare provider or pharmacist can give you recommendations on how to prevent or manage drug interactions. You may require some dose adjustments or close monitoring to avoid adverse effects.

Significant Drug Interactions

Drugs that interact with Singulair usually affect its processing and excretion in the body. Some of the drugs that can cause significant drug interactions with Singulair include the following:

Certain antiseizure medications – Some anticonvulsants can reduce the serum levels of Singulair in the body, probably making it less effective. Usually, there is no need to adjust the dose of Singulair due to this drug interaction. However, you should inform your healthcare provider if your symptoms of asthma or allergy worsen while taking antiseizure medications. Some anticonvulsant drugs that interact with Singulair include:

  • Carbamazepine (Carbatrol, Epitol, Equetro, Tegretol)
  • Fosphenytoin (Cerebyx)
  • Oxcarbazepine (Trileptal)
  • Phenobarbital (Luminal)
  • Pentobarbital (Nembutal)
  • Phenytoin (Dilantin)
  • Primidone (Mysoline)

Certain Antibiotics – Some antibiotics, specifically rifamycin, can decrease the blood levels of Singulair, probably making it less effective. Usually, dose adjustments are not necessary. However, if your symptoms worsen while using rifamycin antibiotics, inform your healthcare provider. Rifamycin antibiotics include:

  • Rifabutin (Mycobutin)
  • Rifampin (Rifadin)
  • Rifapentine (Priftin)

If you are using any of these drugs, consult your healthcare provider of pharmacist. Depending on your condition, your healthcare provider may recommend stopping or changing one of the drugs, changing the dosing schedule of one or both drugs, or discontinuing both medications.

However, an interaction between two drugs does not always require stopping one of the drugs. Talk with your healthcare provider about how to prevent or manage any potential drug interactions.

This medication guide does not discuss all drugs that can potentially interact with Singulair. Inform your healthcare provider or pharmacist about all prescription, nonprescription (over-the-counter), and herbal medications you take. Also discuss with your healthcare provider any health supplement you are taking. It would help if you make a list of all healthcare products you use. Share your list with your healthcare provider or pharmacist so that he or she can make necessary recommendations.

Singulair can potentially interact with alcohol, caffeine, and some street drugs. Discuss with your healthcare provider use of these substances to prevent drug interactions.