• seizure (convulsions);

• worsening of your condition, or symptoms of new illness;

• severe or ongoing nausea and vomiting, headache, fast or uneven heart rate, and trouble sleeping (insomnia);

• coughing up blood or vomit that looks like coffee grounds;

• ongoing fever;

• feeling restless, irritable, nervous, or jittery.

• tremors; or

• urinating more than usual.

Less serious side effects may include:

• mild nausea, loss of appetite, weight loss;

• restlessness, tremor, or insomnia; or

• headache, lightheadedness, or dizziness.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.

What other drugs will affect theophylline?

Before taking theophylline, tell your doctor if you are using any of the following drugs:

• carbamazepine (Carbatrol, Tegretol);

• cimetidine (Tagamet);

• enoxacin (Penetrx);

• ephedrine or similar medications found in cold medicine or diet pills;

• erythromycin (E.E.S., E-Mycin, Ery-Tab);

• fluvoxamine (Luvox);

• propranolol (Inderal, InnoPran);

• rifampin (Rifadin, Rifater, Rifamate, Rimactane);

• St. John's wort; or

• thiabendazole (Mintezol).

This list is not complete and there are many other medicines that can interact with theophylline. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor. Keep a list with you of all the medicines you use and show this list to any doctor or other healthcare provider who treats you.

Where can I get more information?

Your pharmacist can provide more information about theophylline.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.