Disopyramide
Antiarrhythmics
Antiarrhythmics
An oral class IA antiarrhythmic with strong anticholinergic and negative inotropic effects. It can worsen heart failure and cause urinary retention.
Quick facts
- Group
- Antiarrhythmics
- Target
- Cardiac sodium channel Nav1.5 (and muscarinic receptors)
- Key effects
- Dry mouth · Urinary hesitancy and constipation
- Monitor
- ECG · Signs of heart failure · Kidney function
- ATC
- C01BA03
No doses: the clinician sets them by the current guideline.
Mechanism of action
Disopyramide blocks cardiac sodium channels and lengthens repolarisation (class IA: wider QRS and longer QT). It depresses contractility more than other class I drugs and has marked anticholinergic activity, which explains dry mouth, constipation and urinary retention.
- Disopyramide blocks sodium channels and lengthens repolarisation
- Contractility falls (negative inotropic effect)
- Muscarinic block causes anticholinergic effects
Indications
- Documented life-threatening ventricular arrhythmias such as sustained ventricular tachycardia Ventricular tachycardia →
Adverse effects
Common
- Dry mouth
- Urinary hesitancy and constipation
- Blurred vision and dry eyes
Contraindications
- Cardiogenic shock
- Second- or third-degree AV block without a pacemaker
- Congenital long QT
- Hypersensitivity to disopyramide
- Glaucoma, urinary retention, prostatic hypertrophy or myasthenia gravis, unless managed (anticholinergic)
Key interactions
- Other class IA or IC antiarrhythmics and propranolol
- Additive negative inotropy and conduction slowing
- Erythromycin and other CYP3A4 inhibitors
- Higher disopyramide levels, QT prolongation
What is monitored
- ECG: QRS and QT
- Signs of heart failure and blood pressure
- Kidney function
- Blood glucose in at-risk patients
Administration and safety
- Immediate-release and controlled-release capsules are different products: the product is checked.
- In cardiomyopathy or possible decompensation, it is started cautiously without a loading phase.
Pregnancy and breastfeeding
It has been found in fetal blood and can stimulate uterine contractions, so it is used in pregnancy only if clearly needed.
Nursing care
- Ask about difficulty passing urine, constipation and dry mouth, especially in older men.
- Watch for breathlessness, swelling and low blood pressure.
- Teach signs of low blood sugar.
Pharmacokinetics
- Metabolism
- Liver, by CYP3A4
- Elimination
- More than half unchanged in urine, so the dose is reduced in kidney impairment
Test yourself
Think of the answer, then tap the question to see it.
Which two properties set disopyramide apart from other class IA drugs?
Strong negative inotropic effect and marked anticholinergic activity.
Why is disopyramide avoided in glaucoma and prostatic hypertrophy?
Its anticholinergic effect can raise eye pressure and cause urinary retention.
Why is the disopyramide dose reduced in kidney failure?
More than half is excreted unchanged in the urine.
Connections
← Back to the class: Antiarrhythmics
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - DISOPYRAMIDE PHOSPHATE capsule, gelatin coated (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.