Drug side effects
theophylline Side Effects
The reactions most often reported to the FDA for theophylline (also sold as Theo-24, Elixophyllin), with demographics, serious outcomes, and reporting trends.
Data updated 2026-05-15
- 11,723
- FAERS reports
Data from the FDA Adverse Event Reporting System (FAERS), 1995 to 2025. A FAERS report records a temporal association, not proof of cause. See our methodology for how figures are compiled and de-duplicated.
The most commonly reported side effects of theophylline come from 11,723 reports to the FDA, broken down here by frequency, patient demographics, and serious outcomes.
This page analyzes 11,723 reports to the FDA Adverse Event Reporting System (FAERS) for theophylline (Theo-24): the reactions reported most often, who reported them, serious outcomes such as hospitalization, and year-over-year trends. A FAERS report does not prove the drug caused the effect, and report volume tracks how widely a drug is used, not how likely an effect is for any one person. Educational information, not medical advice.
Total Reports
11,723
Reports Mentioning Death
1,708
14.6% of reports — not proof the medicine caused the death
Hospitalizations
5,109
43.6% of reports
Top Indication
Asthma
Most Reported Adverse Reactions
Who Reports Side Effects
Gender Distribution
Age Distribution
Reporting Trend by Year
Reactions in Death Reports
Top reactions reported in 1,708 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| DEATH | 351 |
| CHRONIC OBSTRUCTIVE PULMONARY DISEASE | 200 |
| DYSPNOEA | 185 |
| TOXICITY TO VARIOUS AGENTS | 152 |
| PNEUMONIA | 141 |
| RESPIRATORY FAILURE | 124 |
| COMPLETED SUICIDE | 105 |
| VOMITING | 105 |
| CONDITION AGGRAVATED | 104 |
| ANAEMIA | 103 |
| NAUSEA | 102 |
| SEPSIS | 100 |
| SOMNOLENCE | 88 |
| CARDIAC ARREST | 85 |
| DRUG INTERACTION | 83 |
| ABDOMINAL DISTENSION | 79 |
| GENERAL PHYSICAL HEALTH DETERIORATION | 78 |
| ABDOMINAL PAIN | 76 |
Reactions in Hospitalization Reports
Top reactions in 5,109 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| DYSPNOEA | 1,026 |
| ASTHMA | 850 |
| PNEUMONIA | 595 |
| CHRONIC OBSTRUCTIVE PULMONARY DISEASE | 497 |
| WHEEZING | 477 |
| COUGH | 407 |
| VOMITING | 383 |
| NAUSEA | 379 |
| THERAPEUTIC PRODUCT EFFECT INCOMPLETE | 316 |
| CONDITION AGGRAVATED | 302 |
| HYPERTENSION | 289 |
| FATIGUE | 276 |
| ANXIETY | 271 |
| PRODUCTIVE COUGH | 268 |
| ATRIAL FIBRILLATION | 261 |
| PYREXIA | 257 |
| DIZZINESS | 255 |
| DRUG INTERACTION | 237 |
Nearby, Related Medications
What the FAERS Data Reveals About theophylline Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 11,723 voluntary reports linked to theophylline and its brand equivalents (Theo-24, Elixophyllin), spanning 1995 through 2025. Of those, 1,708 (14.6%) listed death as an outcome and 5,109 (43.6%) involved hospitalization. The most common indication reported alongside adverse events was Asthma.
Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 59% were female and 40% male; age distribution skews toward 45-64, with 2,683 reports in that bracket. The single most reported reaction is dyspnoea with 2,273 submissions, followed by asthma and pneumonia.
How to read these numbers
FAERS is a signal-detection tool, not a scorecard. Reports are voluntary, and a single case may list multiple suspect drugs, so numbers above should not be read as incidence rates or per-patient risk. Widely prescribed drugs naturally accumulate more reports than niche therapies even when individual risk is low. These aggregates are useful for spotting patterns that merit further pharmacovigilance, not for choosing between medications. This page is for educational reference only and is not medical advice, speak with a licensed clinician about any side-effect concerns.
Drugs With a Similar FAERS Report Volume
Other medications with a total FDA adverse-event report count closest to theophylline's 11,723.
Read our methodology - how this data is sourced, computed, and verified.