disopyramide: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
disopyramide: clinical details
Prescribing considerations
- Balance symptomatic benefit against proarrhythmia and cardiac-decompensation risks, particularly with structural heart disease.
- Life-threatening or haemodynamically significant arrhythmias should be initiated in hospital.
- Review glaucoma, prostatic enlargement, constipation, myasthenia gravis, cognitive vulnerability and medicines that lower potassium or prolong QT.
- Renal and hepatic function affect product selection and exposure; the modified-release formulation has stricter restrictions.
Contraindications and cautions
- Hypersensitivity to disopyramide or product excipients.
- Unpaced second- or third-degree atrioventricular block, specified bundle-branch or bifascicular block, pre-existing long-QT syndrome or severe sinus-node dysfunction.
- Severe heart failure unless secondary to the arrhythmia.
- Concomitant antiarrhythmics or other medicines liable to provoke ventricular arrhythmias, particularly torsades de pointes.
- For the selected modified-release product: renal impairment, hepatic impairment and use in children.
Monitoring
- Baseline and follow-up ECG, including QT interval, QRS duration and conduction.
- Serum potassium and correction of electrolyte disturbance.
- Blood glucose, particularly in older, malnourished or diabetic patients and those with renal impairment or heart failure.
- Renal and hepatic function.
- Evidence of heart failure, hypotension, urinary retention, ileus and cognitive or visual anticholinergic effects.
- Consider intraocular-pressure assessment with a personal or family history of glaucoma.
Clinical pharmacology
A class Ia sodium-channel blocker that decreases membrane responsiveness, slows abnormal automaticity and alters refractory periods. Negative inotropy, anticholinergic activity, CYP3A metabolism and substantial renal elimination contribute to its safety profile and interactions.
Formulation and product differences
- Immediate-release capsules and modified-release tablets are not directly interchangeable without prescriber review.
- Modified-release tablets must be swallowed intact and are contraindicated in renal or hepatic impairment and in children under the selected product information.
- The capsule formulation permits consideration in renal or hepatic impairment only with individualised prescribing and close monitoring.
disopyramide preparations and strengths
Capsule
Route: Oral
Strengths: 100 mg
Modified-release tablet
Route: Oral
Strengths: 250 mg
disopyramide interactions
Check all prescribed, over-the-counter and herbal products because some combinations can alter heart rhythm, potassium or disopyramide exposure.
Other antiarrhythmics and QT-prolonging medicines
The combination can worsen rhythm disturbances or increase torsades de pointes risk and is generally contraindicated or avoided.
Macrolide antibiotics and azole antifungals
They may prolong QT and inhibit CYP3A, potentially increasing disopyramide exposure and arrhythmia risk.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.