Rythmol SR Side Effects
Generic name: propafenone
Medically reviewed by Drugs.com. Last updated on Mar 22, 2022.
Note: This document contains side effect information about propafenone. Some of the dosage forms listed on this page may not apply to the brand name Rythmol SR.
Common side effects of Rythmol SR include: constipation, dyspnea, nausea, and dysgeusia. Other side effects include: cardiac rate disturbance, death, atrial flutter, blurred vision, heart murmur, myasthenia, asthenia, diarrhea, first degree atrioventricular block, vomiting, and ecchymoses. See below for a comprehensive list of adverse effects.
For the Consumer
Applies to propafenone: oral capsule extended release, oral tablet
Oral route (Tablet; Capsule, Extended Release)
It is prudent to consider any Class 1C antiarrhythmic to have a significant proarrhythmic risk in patients with structural heart disease. Given the lack of any evidence that these drugs improve survival, antiarrhythmic agents should generally be avoided in patients with non-life-threatening ventricular arrhythmias, even if the patients are experiencing unpleasant, but not life-threatening, symptoms or signs.
Side effects requiring immediate medical attention
Along with its needed effects, propafenone (the active ingredient contained in Rythmol SR) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur while taking propafenone:
- Chest pain
- fast, irregular, or slow heartbeat
- lightheadedness, dizziness, or fainting
- shortness of breath
- swelling of the feet or lower legs
- weight gain
- joint pain
- trembling or shaking
Side effects not requiring immediate medical attention
Some side effects of propafenone may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.
Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- Change in taste or bitter or metallic taste
- Blurred vision
- dryness of the mouth
- nausea or vomiting
- skin rash
- unusual tiredness or weakness
For Healthcare Professionals
Applies to propafenone: oral capsule extended release, oral tablet
Adverse reactions occurred most commonly in the cardiovascular, gastrointestinal, and nervous systems.[Ref]
Common (1% to 10%): Palpitation, angina pectoris, atrial flutter, first-degree atrioventricular block, bradycardia, congestive heart failure, cardiac murmur, left bundle branch block, right bundle branch block, conduction disorders, sinus bradycardia, hypotension, wide complex tachycardia, ventricular tachycardia or ventricular fibrillation, recurrent supraventricular tachycardia
Uncommon (0.1% to 1%): Premature ventricular contractions increased
Frequency not reported: PR interval prolongation, QRS interval prolongation, unstable angina, atrial hypertrophy, cardiac arrest, coronary artery disease, extrasystoles, myocardial infarction, nodal arrhythmia, pericarditis, sinoatrial block, sinus arrest, sinus arrhythmia, supraventricular extrasystoles, ventricular extrasystoles, ventricular hypertrophy, abnormal heart sounds, abnormal pulse, carotid bruit, blood pressure decreased, blood pressure increased, limb arterial embolism, deep limb venous thrombosis, flushing, hematoma, hypertension, hypertensive crisis, labile blood pressure, pallor, peripheral coldness, peripheral vascular disease, thrombosis, intraventricular conduction delay, second-degree atrioventricular block, atrioventricular dissociation, hot flashes, sick sinus syndrome, sinus pause or arrest, supraventricular tachycardia, torsade de pointes, asystole[Ref]
Very common (10% or more): Nausea and/or vomiting (11%)
Common (1% to 10%): Constipation, diarrhea, dry mouth, flatulence
Frequency not reported: Abdominal distention, abdominal pain, duodenitis, dyspepsia, dysphagia, eructation, gastritis, gastroesophageal reflux disease, gingival bleeding, glossitis, glossodynia, gum pain, halitosis, intestinal obstruction, melena, mouth ulceration, pancreatitis, peptic ulcer, rectal bleeding, gastroenteritis[Ref]
Very common (10% or more): Unusual taste (up to 14%)
Common (1% to 10%): Dizziness, headache, tremor, somnolence, ataxia
Uncommon (0.1% to 1%): Seizures
Frequency not reported: Tinnitus, vertigo, sciatica, amnesia, balance impaired, brain damage, cerebrovascular accident, dementia, gait abnormal, hypertonia, hypoesthesia, paralysis, paresthesia, peripheral neuropathy, speech disorder, syncope, tongue hypoesthesia, memory loss, numbness, unusual smell sensation, myasthenia gravis exacerbated
Postmarketing reports: Coma[Ref]
Frequency not reported: Sore throat, atelectasis, breath sounds decreased, chronic obstructive airways disease, cough, epistaxis, hemoptysis, lung disorder, pleural effusion, pulmonary congestion, respiratory failure, rhinitis, throat tightness
Postmarketing reports: Apnea[Ref]
Common (1% to 10%): Chest pain, fatigue, edema, weakness
Frequency not reported: Hearing impaired, feeling hot, malaise, pain, pyrexia, breast pain, death[Ref]
Common (1% to 10%): Ecchymosis
Common (1% to 10%): Hematuria
Frequency not reported: Glycosuria present, prostatic specific antigen increased, ketonuria present, proteinuria present, dysuria, nocturia, oliguria, pyuria, urinary casts, urinary frequency, urinary incontinence, urinary retention, urine abnormal, impotence, prostatism, sperm count decreased[Ref]
Common (1% to 10%): Blood alkaline phosphatase increased
Frequency not reported: Hepatomegaly, ALT increased, AST increased, blood bilirubin increased, gamma-glutamyltransferase increased, cholestasis, hepatitis
Postmarketing reports: Liver abnormalities[Ref]
Common (1% to 10%): Influenza
Uncommon (0.1% to 1%): Positive antinuclear antibody titer[Ref]
Common (1% to 10%): Anorexia
Frequency not reported: Weight decreased, blood cholesterol increased, blood glucose increased, blood triglycerides increased, blood uric acid increased, weight increased, dehydration, diabetes mellitus, gout, hypercholesterolemia, hyperglycemia, hyperlipidemia, hypokalemia
Common (1% to 10%): Blurred vision
Frequency not reported: Eye hemorrhage, eye inflammation, eyelid ptosis, miosis, retinal disorder, visual acuity reduced, vision abnormal, eye irritation[Ref]
Frequency not reported: Blood prolactin increased[Ref]
Frequency not reported: Anemia, lymphadenopathy, spleen disorder, thrombocytopenia, hemorrhage, blood chloride decreased, blood sodium decreased, hemoglobin decreased, neutrophil count decreased, platelet count decreased, prothrombin level decreased, red blood cell count decreased, blood lactate dehydrogenase increased, eosinophil count increased, monocyte count increased, prothrombin level increased, white blood cell count increased, granulocytopenia, leukopenia
Postmarketing reports: Bleeding time increased[Ref]
Frequency not reported: Blood creatinine increased, blood urea increased, renal failure, nephrotic syndrome
Common (1% to 10%): Muscle weakness
More about Rythmol SR (propafenone)
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- Drug class: group I antiarrhythmics
- Other brands
Related treatment guides
1. "Product Information. Rhythmol (propafenone)." Knoll Pharmaceutical Company, Whippany, NJ.
2. "Product Information. Rythmol SR (propafenone)." GlaxoSmithKline, Research Triangle Park, NC.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.