Formoterol Inhalation, oral/nebulization and Theo-Dur

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Using theophylline together with formoterol may increase cardiovascular side effects such as heart palpitations, increased heart and pulse rates, and blood pressure elevations. Combining these medications may also increase the risk of developing hypokalemia, or low blood potassium. Although the hypokalemia associated with these drugs is generally mild and does not cause problems, severe cases can occasionally lead to muscle weakness, paralysis, breathing and swallowing difficulties (due to muscle paralysis), and irregular heart rhythm. Side effects may be more likely if you are receiving formoterol or similar medications in the nebulized, oral, or injectable form. In addition, these medications given orally or by injection may sometimes reduce the blood levels and effects of theophylline. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Let your doctor know if your breathing worsens or you experience nausea, vomiting, constipation, abdominal cramping, confusion, dizziness, lightheadedness, fainting, muscle weakness, muscle cramps, numbness, tingling, rapid heartbeat, chest pain, and/or swelling in the legs or feet, as these may be symptoms of hypokalemia. 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.

MONITOR: Concomitant use of beta-2 adrenergic agonists with theophylline may increase the risk and/or severity of hypokalemia and adverse cardiovascular effects such as palpitation, tachycardia, and blood pressure elevation. Adverse events, especially hypokalemia, may be more likely with systemic or nebulized formulations of beta-2 agonists or high dosages of theophylline. Beta-2 agonists can cause clinically significant but usually transient decreases in serum potassium concentrations, while hypokalemia associated with theophylline often occurs in toxicity. Serious events including rare cases of cardiorespiratory arrest and intestinal pseudo-obstruction have been reported in association with hypokalemia induced by these agents. Moreover, since QT prolongation is a possible side effect of beta-2 agonists, development of hypokalemia may potentiate the risk of torsade de pointes and other serious arrhythmias. Pharmacokinetically, some beta-2 agonists given systemically may decrease the plasma concentrations of theophylline. Albuterol, isoproterenol, and terbutaline have been specifically implicated, usually increasing theophylline clearance by approximately 10% to a third, although some studies with albuterol and terbutaline failed to demonstrate a significant effect on theophylline pharmacokinetics. The interaction also did not occur in studies with fenoterol, formoterol, and metaproterenol. A case report describes a significant increase in theophylline clearance during intravenous administration of albuterol in a 19-month-old child with severe asthma, who subsequently required a threefold increase in theophylline dosage. Theophylline clearance decreased by 50% upon discontinuation of albuterol. In another case, a greater than 4-fold increase in theophylline clearance was reported following the intravenous administration of isoproterenol and methylprednisolone in a critically patient receiving aminophylline and nebulized terbutaline.

MANAGEMENT: Although theophylline and beta-2 agonists are commonly used together to produce bronchodilation, it may be appropriate to monitor patient response as well as serum potassium level, blood pressure and heart rate during coadministration, especially if the beta-2 agonist is administered systemically or by nebulizer. Close monitoring is particularly important in patients with severe asthma, since the potential increases in blood pressure and heart rate may have more serious consequences in the presence of hypoxemia or hypercapnia due to increased myocardial oxygen consumption. Patients should be advised to notify their physician if they experience worsening of their respiratory condition or potential signs and symptoms of hypokalemia such as fatigue, weakness, myalgia, muscle cramps, numbness, tingling, abdominal pain, constipation, palpitation, and irregular heartbeat.

Formoterol Inhalation, oral/nebulization

Generic Name: formoterol

Brand name: Perforomist, Foradil Aerolizer, Foradil Aerolizer>

Synonyms: Formoterol (inhalation), Formoterol

What is Formoterol Inhalation, oral/nebulization?

Theo-Dur

Generic Name: theophylline

Brand name: Elixophyllin, Theo-24, Respbid, T-Phyl, Aerolate III, Slo-Bid Gyrocaps, Slo-Phyllin, Theobid, Theo-Dur, Theolair, Theovent, Bronkodyl, Theo-X, Theo-Time, Theochron, Slo-Phyllin 125, Theoclear LA-130, Aerolate JR, Theolair-SR, Theoclear LA-260, Quibron-T, Quibron-T/SR, Uniphyl, Uni-Dur, Aerolate SR, Slo-Phyllin 80, Theoclear-80, Theo-Dur Sprinkles, Theosol-80, Asmalix, Aquaphyllin, Truxophyllin, Slo-Phyllin 250, TheoCap

Synonyms: Theo-Dur (Oral)

What is Theo-Dur?