Quibron-T/SR Side Effects

Generic name: theophylline

Medically reviewed by Drugs.com. Last updated on Apr 3, 2025.

Note: This document provides detailed information about Quibron-T/SR Side Effects associated with theophylline. Some dosage forms listed on this page may not apply specifically to the brand name Quibron-T/SR.

Applies to theophylline: oral capsule extended release 24 hr, oral elixir, oral solution, oral tablet extended release, oral tablet extended release 12 hr, oral tablet extended release 24 hr.

Other dosage forms:

• intravenous solution

Precautions

It is very important that your doctor check the progress of you or your child at regular visits, especially for the first few weeks after you begin using this medicine. Blood tests may be needed to check for unwanted effects.

A change in your usual behavior or physical well-being may affect the way this medicine works in your body. Tell your doctor if you or your child:

• Have had a fever of 102 degrees F or higher for at least 24 hours or more.
• Have started or stopped smoking tobacco or marijuana in the last few weeks.
• Have started or stopped taking another medicine in the last few weeks.
• Have changed your diet in the last few weeks.

Stop using this medicine and check with your doctor right away if you or your child have the following symptoms while using this medicine: nausea or vomiting that continues, headaches, trouble with sleeping, seizures, or irregular heartbeats.

Do not stop or change the dose of this medicine without checking first with your doctor.

Before you have any medical tests, tell the medical doctor in charge that you or your child are using this medicine. The results of some tests may be affected by this medicine.

This medicine may add to the central nervous system (CNS) stimulant effects of caffeine-containing foods or beverages such as chocolate, cocoa, tea, coffee, and cola drinks. Avoid eating or drinking large amounts of these foods or beverages while using this medicine. If you have questions about this, check with your doctor.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, and herbal (e.g., St. John's wort) or vitamin supplements.

Serious side effects of Quibron-T/SR

Along with its needed effects, theophylline (the active ingredient contained in Quibron-T/SR) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking theophylline:

Get emergency help immediately if any of the following symptoms of overdose occur while taking theophylline:

Symptoms of overdose

• abdominal or stomach pain
• blurred vision
• confusion
• confusion about identity, place, and time
• dark-colored urine
• decrease in frequency of urination
• decreased urine
• diarrhea
• difficulty in passing urine (dribbling)
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• dry mouth
• fast, pounding, or irregular heartbeat or pulse
• fever
• increased thirst
• irregular heartbeat
• loss of appetite
• mood changes
• muscle cramps or spasms
• muscle pain or stiffness
• nausea or vomiting
• nervousness
• numbness or tingling in the hands, feet, or lips
• pain or discomfort in the arms, jaw, back, or neck
• painful urination
• shakiness in the legs, arms, hands, or feet
• shortness of breath
• sweating
• unusual tiredness or weakness
• vomiting of blood or material that looks like coffee grounds

Other side effects of Quibron-T/SR

Some side effects of theophylline may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

For healthcare professionals

Applies to theophylline: compounding powder, intravenous solution, oral capsule, oral capsule extended release, oral elixir, oral solution, oral syrup, oral tablet, oral tablet extended release.

General adverse events

Adverse events are generally mild when theophylline (the active ingredient contained in Quibron-T/SR) levels are under 20 mcg/mL; the most common adverse events were caffeine-like adverse effects like nausea, vomiting, headache, and insomnia.

When theophylline concentrations exceed 20 mcg/mL, many adverse effects may occur, including persistent vomiting, cardiac arrhythmias, and intractable seizures, which may be fatal.^[Ref]

Cardiovascular

• Very common (10% or more): Sinus tachycardia (up to 100% in acute overdose, up to 100% with chronic overdose), ventricular arrhythmias with hemodynamic instability (14% in acute overdose, 40% with chronic overdose), other supraventricular tachycardias (21% in acute overdose, 14% with chronic overdose), ventricular premature beats (21% in acute overdose, 19% with chronic overdose), hypotension/shock (21% in acute overdose, 8% with chronic overdose), atrial fibrillation or flutter (1% in acute overdose, 12% with chronic overdose)
• Common (1% to 10%): Multifocal atrial tachycardia (2% with chronic overdose)
• Frequency not reported: Cardiac arrhythmias (at serum concentrations over 20 mcg/mL), multifocal atrial tachycardia and flutter (at serum concentrations 15 mcg/mL and over in hypoxia secondary to COPD patients)^[Ref]

Nervous system

• Very common (10% or more): Tremors (38% in acute overdose, 16% with chronic overdose), seizures (14% in acute overdose, 14% with chronic overdose)
• Frequency not reported: Headache, intractable seizures (at serum concentrations over 20 mcg/mL), seizures^[Ref]

A few seizures have been reported in patients with underlying neurological disease or in elderly patients with serum theophylline under 20 mcg/mL.

Seizures in elderly patients with serum theophylline under 20 mcg/mL may be due to decreased protein binding causing higher unbound (pharmacologically active) theophylline levels.

Seizures in patients with serum theophylline under 20 mcg/mL were generally milder (than those from overdose) such as being transient, not requiring anticonvulsants, and no neurological residuals.

Consider the possibility of non-convulsive status epilepticus in patients with abnormal central nervous system function and theophylline use.^[Ref]

Gastrointestinal

• Very common (10% or more): Vomiting (93% in acute overdose, 61% with chronic overdose), abdominal pain (21% in acute overdose, 12% with chronic overdose), diarrhea (14% with chronic overdose)
• Common (1% to 10%): Hematemesis (2% with chronic overdose)
• Frequency not reported: Nausea, vomiting, persistent vomiting (at serum concentrations over 20 mcg/mL), diarrhea^[Ref]

Metabolic

• Very common (10% or more): Hyperglycemia (98% in acute overdose, 18% with chronic overdose), hypokalemia (85% in acute overdose, 44% with chronic overdose), acid/base disturbance (34% in acute overdose, 9% with chronic overdose)
• Frequency not reported: Hypercalcemia (in a hyperthyroid patient), hypervolemia^[Ref]

Psychiatric

• Very common (10% or more): Nervousness (64% in acute overdose, 21% with chronic overdose), disorientation (7% in acute overdose, 12% with chronic overdose)
• Frequency not reported: Insomnia, irritability, restlessness^[Ref]

Musculoskeletal

• Uncommon (0.1% to 1%): Rhabdomyolysis (7% in acute overdose)
• Frequency not reported: Fine skeletal muscle tremors^[Ref]

Other

• Very common (10% or more): Death (21% in acute overdose, 10% with chronic overdose)
• Frequency not reported: Febrile response^[Ref]

Genitourinary

• Frequency not reported: Transient diuresis^[Ref]

Local

• Frequency not reported: Infection at the site of injection, venous thrombosis or phlebitis extending from the site of injection, extravasation^[Ref]

See also:

Further information

Quibron-T/SR side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer