Cisapride: Do Not Use Due to Fatal Cardiac Risk
Cisapride has been withdrawn from the market due to an increased risk of fatal cardiac arrhythmias related to QT interval prolongation and should not be used in clinical practice. 1
Critical Safety Information
Why Cisapride Was Withdrawn
Cisapride is a 5-HT4 agonist that enhances acetylcholine release in the myenteric plexus and was previously used for gastrointestinal dysmotility. Despite showing efficacy in improving abdominal pain, gastric emptying, and migrating motor complexes (MMCs) in controlled trials, the drug was withdrawn due to fatal cardiac arrhythmias caused by prolonged QT interval 1. Between 1993 and 2000,341 cases of ventricular arrhythmias were reported to the FDA, including 80 deaths 2. The drug was removed from general distribution in the United States in July 2000 3.
Mechanism of Cardiac Toxicity
The cardiac risk stems from:
- QT interval prolongation leading to torsades de pointes and ventricular arrhythmias
- Particularly dangerous when combined with medications that inhibit cytochrome P450 3A4 (cisapride's primary metabolic pathway), causing elevated drug levels 2
- Risk amplified in patients with underlying cardiac conditions or electrolyte disturbances 1
Absolute Contraindications
Do not prescribe cisapride with any of the following:
Drug Interactions (CYP3A4 Inhibitors)
- Macrolide antibiotics: clarithromycin, erythromycin, troleandomycin (azithromycin is safe alternative) 2
- Azole antifungals: fluconazole, itraconazole, ketoconazole 2
- HIV protease inhibitors: amprenavir, indinavir, nelfinavir, ritonavir 2
- Antidepressants: nefazodone, fluvoxamine (avoid fluoxetine; alternatives include citalopram, paroxetine, sertraline) 2
- Other: amiodarone, cimetidine, diltiazem, verapamil, metronidazole, grapefruit juice 2
Drugs Prolonging QT Interval
- Class Ia and III antiarrhythmics
- Antipsychotics (haloperidol, phenothiazines)
- Tricyclic and tetracyclic antidepressants 2
Patient Conditions
- History of cardiac dysrhythmias
- Congenital long QT syndrome
- Uncorrected electrolyte disturbances (hypokalemia, hypomagnesemia, hypocalcemia)
- Significant hepatic dysfunction 4, 5
Historical Dosing (For Reference Only)
When cisapride was available, recommended dosing was:
- Maximum pediatric dose: 0.8 mg/kg/day divided into 3-4 doses (not exceeding 40 mg/day) 4
- Adult dose: 900 mg/day was mentioned in some contexts 1
ECG monitoring was required before initiation and after 3 days of treatment in at-risk patients, with QTc intervals >470 milliseconds considered abnormal 4.
Safer Alternatives
Use prucalopride instead - a selective 5-HT4 receptor agonist that does not affect the QT interval and lacks the cardiac risks of cisapride. Prucalopride has no significant action on 5-HT1B/D receptors or cardiac potassium channels 1.
Other alternatives for gastrointestinal dysmotility:
- Erythromycin (motilin agonist): 900 mg/day for absent/impaired migrating complexes, though subject to tachyphylaxis 1
- Octreotide: 50-100 μg once or twice daily, particularly effective in systemic sclerosis 1
Critical Clinical Pitfall
Despite FDA warnings in 1995,1998, and 1999, contraindicated coprescribing remained common - studies showed 3.4% of cisapride prescriptions overlapped with contraindicated drugs even after warnings, with 89% dispensed by the same pharmacies 6, 3. This regulatory failure underscores that the only safe approach is complete avoidance of cisapride in modern practice.