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Understanding Asthma Medications (cont.)


Theophylline (Theo-24, Theolair, Theo-Dur, Slo-Bid, Slo-Phyllin) may be prescribed to take with other controller medications.

How methylxanthines work

Methylxanthines are related to caffeine. These drugs provide mild to moderate relaxation of muscles in the airway to decrease bronchospasm. Essentially, they work as long-acting bronchodilators. These medications may have a mild antiinflammatory effect.

Who should not use these medications

  • Individuals who are allergic to methylxanthines
  • Individuals with abnormal heart rhythms that are poorly controlled
  • Individuals with seizures (epilepsy) that are poorly controlled
  • Individuals diagnosed with hyperactive thyroid
  • Individuals with active peptic ulcer disease


Methylxanthines are administered orally as tablets, capsules, liquid preparations, or sprinkles (tiny beads that may be sprinkled on the tongue or on soft food). Some oral preparations are available in long-acting doses, allowing the dose to be taken once or twice each day. Your doctor will adjust the dose to maintain specific blood levels known to be effective to decrease bronchospasm.

Drug or food interactions

Ingesting large amounts of caffeine contained in coffee, tea, or soft drinks may increase theophylline side effects. Some drugs that may increase theophylline blood levels include cimetidine (Tagamet), erythromycin (E-Mycin, E.E.S.), and ciprofloxacin (Cipro). Some drugs that may decrease theophylline blood levels include phenytoin (Dilantin) and carbamazepine (Tegretol). Check with your doctor or pharmacist before taking or stopping other medications to know how your theophylline blood levels will be affected by the change.

Side effects

Side effects include severe nausea or vomiting, tremors, muscle twitching, seizures, severe weakness or confusion, and irregular heartbeat. Less severe side effects include heartburn, loss of appetite, upset stomach, nervousness, restlessness, insomnia, headache, and loose bowel movements.

Medically Reviewed by a Doctor on 8/15/2014

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