Oxybutynin: uses, appearance and warnings

Oxybutynin chloride tablets are indicated for the relief of symptoms of bladder instability associated with voiding in patients with uninhibited neurogenic or reflex neurogenic bladder (i.e., urgency, frequency, urinary leakage, urge incontinence, dysuria).

Oxybutynin Chloride Tablets USP, 5 mg, are round, blue, scored tablets debossed "5" and "T" on one side separated by a vertical score and plain on the reverse side. The tablets are supplied as follows: Bottles of 100: NDC 52817-260-10 Bottles of 500: NDC 52817-260-50 Oxybutynin Chloride Tablets USP, 2.5 mg, are round, blue, debossed "1" and "T" on one side and plain on the reverse side. The tablets are supplied as follows: • Bottles of 100: NDC 52817-261-10

Oxybutynin chloride is contraindicated in patients with urinary retention, gastric retention and other severe decreased gastrointestinal motility conditions, uncontrolled narrow-angle glaucoma and in patients who are at risk for these conditions. Oxybutynin chloride is also contraindicated in patients who have demonstrated hypersensitivity to the drug substance or other components of the product.

Angioedema of the face, lips, tongue and/or larynx has been reported with oxybutynin. In some cases, angioedema occurred after the first dose. Angioedema associated with upper airway swelling may be life-threatening. If involvement of the tongue, hypopharynx, or larynx occurs, oxybutynin should be promptly discontinued and appropriate therapy and/or measures necessary to ensure a patent airway should be promptly provided.

The safety and efficacy of oxybutynin chloride was evaluated in a total of 199 patients in three clinical trials. These participants were treated with oxybutynin chloride 5 to 20 mg/day for up to 6 weeks. Table 3 shows the incidence of adverse events judged by investigators to be at least possibly related to treatment and reported by at least 5% of patients. The most common adverse events reported by patients receiving oxybutynin chloride 5 to 20 mg/day were the expected side effects of anticholinergic agents. The incidence of dry mouth was dose-related. In addition, the following adverse events were reported by 1 to < 5% of patients using oxybutynin chloride (5 to 20 mg/day) in all studies. …

The concomitant use of oxybutynin with other anticholinergic drugs or with other agents which produce dry mouth, constipation, somnolence (drowsiness), and/or other anticholinergic-like effects may increase the frequency and/or severity of such effects. Anticholinergic agents may potentially alter the absorption of some concomitantly administered drugs due to anticholinergic effects on gastrointestinal motility. This may be of concern for drugs with a narrow therapeutic index. Anticholinergic agents may also antagonize the effects of the prokinetic agents, such as metoclopramide. Mean oxybutynin chloride plasma concentrations were approximately 3 to 4 fold higher when oxybutynin chloride was administered with ketoconazole, a potent CYP3A4 inhibitor. …