What the label lists and what reports show
Oxybutynin side effects
Oxybutynin's FDA label: “The most common (incidence ≥5%) adverse reactions were dry mouth, constipation, diarrhea, headache, somnolence, and dizziness.” FAERS holds 37,662 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is fatigue (2,279 reports).
- Generic listed
Check it at the source: the oxybutynin FDA label on DailyMed (effective December 16, 2025, Accord Healthcare, Inc.); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of OXYTROL?OXYTROL may cause serious side effects, including: • inability to empty your bladder (urinary retention). OXYTROL may increase your chances of not being able to empty your bladder if you have a blockage at the base of your bladder that decreases or stops the flow of urine into the urethra, the tube that carries urine out of the body (bladder outlet obstruction). Tell your doctor right away if you are unable to empty your bladder. • increased risk of stomach and esophagus problems in certain p eople. OXYTROL may cause stomach and esophagus problems in people who have a history of stomach or intestinal blockage, ulcerative colitis, intestinal atony, hiatal hernia, gastroesophageal reflux disease, or who are taking certain medicines called bisphosphonates. • central nervous system effects. […]
Source: FDA drug label (OXYTROL), Allergan, Inc., effective May 29, 2024 (SPL set 20dee37f-1412-44ed-9e8b-f4379ce23eb0), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common (incidence ≥5%) adverse reactions were dry mouth, constipation, diarrhea, headache, somnolence, and dizziness.
Table 1: Adverse Drug Reactions Reported by ≥ 1% of Oxybutynin Chloride Extended-Release Tablets-treated Adult Subjects in Five Double-blind, Controlled Clinical Trials of Oxybutynin Chloride Extended-Release Tablets
| System/Organ Class Preferred Term | Oxybutynin Chloride Extended-Release Tablets 5 to 30 mg/day n = 774 % | Oxybutynin IR IR = immediate release 5 to 20 mg/day n = 199 % |
|---|---|---|
| Insomnia | 3.0 | 5.5 |
| Headache | 7.5 | 8.0 |
| Somnolence | 5.6 | 14.1 |
| Dizziness | 5.0 | 16.6 |
| Dysgeusia | 1.6 | 1.5 |
| Vision blurred | 4.3 | 9.6 |
| Dry eye | 3.1 | 2.5 |
| Cough | 1.9 | 3.0 |
| Oropharyngeal pain | 1.9 | 1.5 |
| Dry throat | 1.7 | 2.5 |
| Nasal dryness | 1.7 | 4.5 |
| Dry mouth | 34.9 | 72.4 |
| Constipation | 8.7 | 15.1 |
| Diarrhea | 7.9 | 6.5 |
| Dyspepsia | 4.5 | 6.0 |
| Nausea | 4.5 | 11.6 |
| Abdominal pain | 1.6 | 2.0 |
| Vomiting | 1.3 | 1.5 |
| Flatulence | 1.2 | 2.5 |
| Gastro-esophageal reflux disease | 1.0 | 0.5 |
| Dry skin | 1.8 | 2.5 |
| Pruritus | 1.3 | 1.5 |
| Dysuria | 1.9 | 2.0 |
| Urinary hesitation | 1.9 | 8.5 |
| Urinary retention | 1.2 | 3.0 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe most common (incidence ≥5%) adverse reactions were dry mouth, constipation, diarrhea, headache, somnolence, and dizziness. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Accord Healthcare Inc. at 1-866-941-7875 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, the adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The safety and efficacy of oxybutynin chloride extended-release tablets (5 to 30 mg/day) was evaluated in 774 adult subjects who participated in five double-blind, controlled clinical trials. In four of the five studies, oxybutynin IR (5 to 20 mg/day in 199 subjects) was an active comparator. Adverse reactions reported by ≥ 1% of subjects are shown in Table 1.
Source: FDA drug label, Accord Healthcare, Inc., effective December 16, 2025 (SPL set 61496a1e-17bf-4f45-a20c-5bb98fe545ee), via openFDA; the full label on DailyMed
What do FAERS reports show?
37,662 reports list oxybutynin among the medicines taken, each a report of something that happened, not proof the medicine caused it; 2,238 are coded as a death and 9,373 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 22 reactions below, 11 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Oxybutynin: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions