ADVERSE REACTIONS Adverse Events with Oxybutynin Chloride Extended-release Tablets The safety and efficacy of oxybutynin chloride was evaluated in a total of 580 participants who received oxybutynin chloride extended-release tablets in four clinical trials (429 patients) and four pharmacokinetic studies (151 healthy volunteers). The 429 patients were treated with 5 to 30 mg/day for up to 4.5 months. Three of the four clinical trials allowed dose adjustments based on efficacy and adverse events and one was a fixed dose escalation design. Safety information is provided for 429 patients from these three controlled clinical studies and one open-label study in the first column of Table 3 below. Adverse events from two additional fixed dose, active controlled, 12-week treatment duration, post-marketing studies, in which 576 patients were treated with oxybutynin chloride extended-release tablets 10 mg/day, are also listed in Table 3 (second column). The adverse events are reported regardless of causality. Table 3 Incidence (%) of Adverse Events Reported by ≥ 5% of Patients Using Oxybutynin Chloride Extended-release Tablets (5 to 30 mg/day) and % of Corresponding Adverse Events in Two Fixed Dose (10 mg/day) Studies Body System Adverse Event Oxybutynin Chloride ER Tablets 5 to 30 mg/day (n = 429) Oxybutynin Chloride ER Tablets 10 mg/day (n = 576) General headache 10 6 asthenia 7 3 pain 7 4 Digestive dry mouth 61 29 constipation 13 7 diarrhea 9 7 nausea 9 2 dyspepsia 7 5 Nervous somnolence 12 2 dizziness 6 4 Respiratory rhinitis 6 2 Special senses blurred vision 8 1 dry eyes 6 3 Urogenital urinary tract infection 5 5 The most common adverse events reported by the 429 patients receiving 5 to 30 mg/day oxybutynin chloride extended-release tablets were the expected side effects of anticholinergic agents. The incidence of dry mouth was dose related. The discontinuation rate for all adverse events was 6.8% in the 429 patients from the four studies of efficacy and safety who received 5 to 30 mg/day. The most frequent adverse event causing early discontinuation of study medication was nausea (1.9%), while discontinuation due to dry mouth was 1.2%. In addition, the following adverse events were reported by ≥ 1 to < 5% of all patients who received oxybutynin chloride extended-release tablets in the six adjustable and fixed dose efficacy and safety studies. Infections and Infestations: nasopharyngitis, upper respiratory tract infection, sinusitis, bronchitis, cystitis; Psychiatric Disorders: insomnia, depression, nervousness, confusional state; Nervous System Disorders: dysgeusia; Cardiac Disorders: palpitations; Vascular Disorders: hypertension; Respiratory, Thoracic and Mediastinal Disorders: nasal dryness, cough, pharyngolaryngeal pain, dry throat; Gastrointestinal Disorders: gastroesophageal reflux disease, abdominal pain, loose stools, flatulence, vomiting; Skin and Subcutaneous Tissue Disorders: dry skin, pruritis; Musculoskeletal and Connective Tissue Disorders: back pain, arthralgia, pain in extremity; Renal and Urinary Disorders: urinary retention, urinary hesitation, dysuria; General Disorders and Administration Site Conditions: fatigue, edema peripheral, asthenia, chest pain; Investigations: blood pressure increased. Post-Marketing Surveillance Because post-marketing reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. The following additional adverse drug reactions have been reported from worldwide post-marketing experience with oxybutynin chloride extended-release tablets: Psychiatric Disorders: psychotic disorder, agitation, hallucinations, memory impairment; Nervous System Disorders: convulsions; Cardiac Disorders: arrhythmia; tachycardia, QT interval prolongation; Vascular Disorders: flushing; Skin and Subcutaneous Tissue Disorders: rash; Renal and Urinary Disorders: impotence; Injury, Poisoning and Procedural Complications: fall. Additional adverse events reported with some other oxybutynin chloride formulations include: cycloplegia, mydriasis, and suppression of lactation.