Theophylline Side Effects

Brand Names: Theochron, Elixophyllin, TheoCap, Theolair, Uniphyl, Quibron-T, Theo-24

Please note - some side effects for Theophylline may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Theophylline - for the Consumer

Theophylline

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Theophylline:

Mild and temporary changes in behavior; temporary increased urination.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); confusion; diarrhea; dizziness; fast breathing; heart rhythm problems or irregular heartbeats; nausea; persistent headache; seizures; sleeplessness; tremors; vomiting.

Theophylline Elixir

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Theophylline Elixir:

Mild and temporary changes in behavior; temporary increased urination.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); confusion; diarrhea; dizziness; fast breathing; heart rhythm problems or irregular heartbeats; nausea; persistent headache; seizures; sleeplessness; tremors; vomiting.

Theophylline Sustained-Release Capsules

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Theophylline Sustained-Release Capsules:

Mild and temporary changes in behavior; temporary increased urination.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); confusion; diarrhea; dizziness; fast breathing; heart rhythm problems or irregular heartbeats; nausea; persistent headache; seizures; sleeplessness; tremors; vomiting.

Theophylline Sustained-Release Tablets

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Theophylline Sustained-Release Tablets:

Mild and temporary changes in behavior; temporary increased urination.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); confusion; diarrhea; dizziness; fast breathing; heart rhythm problems or irregular heartbeats; nausea; persistent headache; seizures; sleeplessness; tremors; vomiting.

Theophylline Side Effects - for the Professional

Theophylline

Adverse reactions associated with Theophylline are generally mild when peak serum Theophylline concentrations are <20 mcg/mL and mainly consist of transient caffeine-like adverse effects such as nausea, vomiting, headache, and insomnia. When peak serum Theophylline concentrations exceed 20 mcg/mL, however, Theophylline produces a wide range of adverse reactions including persistent vomiting, cardiac arrhythmias, and intractable seizures which can be lethal. The transient caffeine-like adverse reactions occur in about 50% of patients when Theophylline therapy is initiated at doses higher than recommended initial doses (e.g., >300 mg/day in adults and >12 mg/kg/day in children beyond 1 year of age). During the initiation of Theophylline therapy, caffeine-like adverse effects may transiently alter patient behavior, especially in school age children, but this response rarely persists. Initiation of Theophylline therapy at a low dose with subsequent slow titration to a predetermined age-related maximum dose will significantly reduce the frequency of these transient adverse effects. In a small percentage of patients (<3% of children and <10% of adults) the caffeine-like adverse effects persist during maintenance therapy, even at peak serum Theophylline concentrations within the therapeutic range (i.e., 10-20 mcg/mL). Dosage reduction may alleviate the caffeine-like adverse effects in these patients, however, persistent adverse effects should result in a reevaluation of the need for continued Theophylline therapy and the potential therapeutic benefit of alternative treatment.

Other adverse reactions that have been reported at serum Theophylline concentrations <20 mcg/mL include diarrhea, irritability, restlessness, fine skeletal muscle tremors, and transient diuresis. In patients with hypoxia secondary to COPD, multifocal atrial tachycardia and flutter have been reported at serum Theophylline concentrations ≥15 mcg/mL. There have been a few isolated reports of seizures at serum Theophylline concentrations <20 mcg/mL in patients with an underlying neurological disease or in elderly patients. The occurrence of seizures in elderly patients with serum Theophylline concentrations <20 mcg/mL may be secondary to decreased protein binding resulting in a larger proportion of the total serum Theophylline concentration in the pharmacologically active unbound form. The clinical characteristics of the seizures reported in patients with serum Theophylline concentrations <20 mcg/mL have generally been milder than seizures associated with excessive serum Theophylline concentrations resulting from an overdose (i.e., they have generally been transient, often stopped without anticonvulsant therapy, and did not result in neurological residua).

Theophylline Elixir

Adverse reactions associated with Theophylline are generally mild when peak serum Theophylline concentrations are <20 mcg/mL and mainly consist of transient caffeine-like adverse effects such as nausea, vomiting, headache, and insomnia. When peak serum Theophylline concentrations exceed 20 mcg/mL, however, Theophylline produces a wide range of adverse reactions including persistent vomiting, cardiac arrhythmias, and intractable seizures which can be lethal. The transient caffeine-like adverse reactions occur in about 50% of patients when Theophylline therapy is initiated at doses higher than recommended initial doses (e.g.,>300 mg/day in adults and >12 mg/kg/day in children beyond >1 year of age). During the initiation of Theophylline therapy, caffeine-like adverse effects may transiently alter patient behavior, especially in school age children, but this response rarely persists. Initiation of Theophylline therapy at a low dose with subsequent slow titration to a predetermined age-related maximum dose will significantly reduce the frequency of these transient adverse effects. In a small percentage of patients (<3% of children and <10% of adults) the caffeine-like adverse effects persist during maintenance therapy, even at peak serum Theophylline concentrations within the therapeutic range (i.e., 10-20 mcg/mL). Dosage reduction may alleviate the caffeine-like adverse effects in these patients, however, persistent adverse effects should result in a reevaluation of the need for continued Theophylline therapy and the potential therapeutic benefit of alternative treatment.

Other adverse reactions that have been reported at serum Theophylline concentrations <20 mcg/mL include diarrhea, irritability, restlessness, fine skeletal muscle tremors, and transient diuresis. In patients with hypoxia secondary to COPD, multifocal atrial tachycardia and flutter have been reported at serum Theophylline concentrations >15 mcg/mL. There have been a few isolated reports of seizures at serum Theophylline concentrations <20 mcg/mL in patients with an underlying neurological disease or in elderly patients. The occurrence of seizures in elderly patients with serum Theophylline concentrations <20 mcg/mL may be secondary to decreased protein binding resulting in a larger proportion of the total serum Theophylline concentration in the pharmacologically active unbound form. The clinical characteristics of the seizures reported in patients with serum Theophylline concentrations <20 mcg/mL have generally been milder than seizures associated with excessive serum Theophylline concentrations resulting from an overdose (i.e., they have generally been transient, often stopped without anticonvulsant therapy, and did not result in neurological residua).

Side Effects by Body System

General

The majority of side effects have been dependent on the serum concentration. Generally, serum concentrations of theophylline ranging from 10 to 20 mcg/mL are considered therapeutic, and serum concentrations greater than 20 mcg/mL are associated with greater toxicity.

There are several factors which may predispose a patient to higher serum concentrations and, thus, toxicity. These factors may include increased age, concomitant drugs which reduce the clearance of theophylline, hypothyroidism, congestive heart failure, liver disease, renal failure, and alterations in smoking habits. One series of patients with theophylline intoxication had recent upper respiratory tract infections.

The nature of acute toxicity of theophylline differs from chronic toxicity. Acute overdose is associated with higher theophylline concentrations and younger patients. In acute overdose the severity of toxicity is correlated with peak serum concentrations. Chronic overdosage is seen more commonly in older patients, and severe toxicity may occur with serum concentrations which are much lower than those seen in severe acute toxicity. In these patients, age is a predictor of severe toxicity.

Gastrointestinal

Gastrointestinal side effects have included anorexia, nausea, vomiting, and abdominal pain. Theophylline may also cause locally-mediated gastrointestinal upset.

Nervous system

Nervous system side effects have included generalized seizures, most commonly in patients with elevated serum concentrations, although seizures have occurred at therapeutic concentrations. Theophylline may also cause nervousness and tremor at therapeutic dosages, which become worse as serum concentrations increase.

The mechanism of theophylline-induced seizures has not been determined. Seizures are generally focal with secondary generalization. Permanent neurologic deficits have been reported and morbidity may be high, especially in the elderly, patients with severe underlying disease, and patients with prolonged, uncontrolled seizure activity. The onset of seizures is not always preceded by less severe symptoms of theophylline toxicity. Patients with an abnormal neurologic history, including a history of seizures, cerebral infarct, or head trauma, may be predisposed to seizure activity. If theophylline is used in these types of patients, serum concentrations should be monitored closely and maintained in the low, therapeutic range.

Cardiovascular

Cardiovascular side effects have included increases in heart rate which have progressed to supraventricular tachycardia or ventricular tachycardia. Patients with a history of arrhythmias may be predisposed to this effect. Hypotension has occurred with rapid intravenous administration.

Theophylline serum concentrations have been a significant predictor of arrhythmias. One study reported multifocal atrial tachycardia in 8% and 16% of patients with a serum concentration between 10 and 20 mcg/mL and greater than 20 mcg/mL, respectively. The onset of serious arrhythmias is not always preceded by less severe signs of theophylline toxicity.

Elevated serum CK-MB levels have been associated with theophylline toxicity in the absence of cardiac disease. CK-MB levels have returned to normal following discontinuation of theophylline therapy.

Metabolic

Metabolic side effects have included hypokalemia, hyperglycemia, respiratory alkalosis, hypophosphatemia, and hypomagnesemia, especially in the situation of acute overdosage. The magnitude of these abnormalities have been correlated with theophylline concentrations. Hypercalcemia has been reported in a patient with hyperthyroid disease with theophylline at therapeutic concentrations.

In one group of patients with theophylline concentrations greater than 20 mcg/mL, hyperglycemia was present in approximately 50%, hypokalemia in 15%, and hypomagnesemia in 20%. Hyponatremia and hypophosphatemia were seen less frequently.

Genitourinary

Genitourinary side effects have included urinary retention.

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