Darifenacin, oxybutynin, solifenacin, tolterodine, and trospium are contraindicated in patients at risk of or with known urinary or gastric retention or uncontrolled angle-closure glaucoma. Tolterodine and trospium are also contraindicated in myasthenia gravis (3
). Flavoxate is contraindicated in patients with pyloric or duodenal obstruction, obstructive intestinal lesions or ileus, achalasia, gastrointestinal hemorrhage, or obstructive uropathies of the lower urinary tract. In patients with known hypersensitivity to the specific product or any of its components, use is contraindicated. Because of the risk of urinary retention, darifenacin, oxybutynin, solifenacin, tolterodine, and trospium should be used with caution in patients with clinically important bladder outflow obstruction.
The antimuscarinic agents oxybutynin, tolterodine, trospium, solifenacin, and darifenacin may decrease gastrointestinal motility. Caution should be used in patients with severe constipation, intestinal atony, ulcerative colitis, or myasthenia gravis. Since diarrhea may be a symptom of partial intestinal obstruction, especially in patients with ileostomies or colostomies, the possibility of intestinal obstruction should be excluded before these agents are administered to patients with diarrhea. Because of the risk of gastric retention, darifenacin, oxybutynin, tolterodine, and trospium should be used with caution in patients with obstructive gastrointestinal disorders (e.g., pyloric stenosis). Fecal impaction, colonic obstruction, and intestinal obstruction have been reported rarely with solifenacin 10 mg daily. Severe constipation has been reported with darifenacin. Chronic constipation persisting for up to 9 months and requiring hospitalization was reported in at least one patient receiving darifenacin.
Oxybutynin also should be used with caution in patients with gastroesophageal reflux and/or in patients receiving oxybutynin concomitantly with drugs that can cause or exacerbate esophagitis (e.g., bisphosphonates). As with other nondeformable material, oxybutynin ER tablets should be used with caution in patients with preexisting severe gastrointestinal narrowing (pathologic or iatrogenic) since obstruction may occur. Tolterodine, solifenacin, darifenacin, and trospium should be used only if the potential benefits outweigh the risks in patients being treated for angle-closure glaucoma and then only when careful monitoring is available. Flavoxate, oxybutynin, and tolterodine should be administered with caution to patients performing hazardous tasks requiring mental alertness or physical coordination because of possible drowsiness, dizziness, and blurred vision. Alcohol or other sedative drugs may enhance these effects.
Solifenacin and tolterodine have been observed to cause prolongation of the QT interval. Caution should be used if a patient has a history of QT prolongation or is receiving class 1A or III antiarrhythmic agents that prolong the QT interval. In a study on the effects of solifenacin on QT interval, a dosage of 30 mg daily (three times the maximum recommended dosage) had a greater effect in prolonging the QT interval than a dosage of 10 mg daily. Prolongation of the QTc
interval has been observed following administration of therapeutic (2 mg twice daily) and supratherapeutic (4 mg twice daily) dosages of tolterodine in healthy adults. Administration of oxybutynin during hot weather can cause heat exhaustion (i.e., fever and heat stroke secondary to suppression of sweating). The possibility that these agents, especially oxybutynin, may aggravate the symptoms of hyperthyroidism, coronary heart disease, congestive heart failure, cardiac arrhythmias, hiatal hernia, tachycardia, hypertension, myasthenia gravis, or prostatic hypertrophy should be considered when prescribing (3