Chemical formula: C₂₁H₂₇NO₃ Molecular mass: 341.444 g/mol PubChem compound: 4932
Propafenone interacts in the following cases:
Medicinal products that inhibit CYP2D6, CYP1A2 and CYP 3A4 e.g. ketoconazole, cimetidine, quinidine, erythromycin and grapefruit juice might lead to increased levels of propafenone. When propafenone is administered with inhibitors of these enzymes, the patients should be closely monitored and the dose adjusted accordingly.
Coadministration of propafenone hydrochloride with drugs metabolised by CYP2D6 (such as venlafaxine) might lead to increased levels of these drugs.
Elevated levels of plasma propafenone may occur when propafenone is used concomitantly with SSRIs, such as fluoxetine and paroxetine. Concomitant administration of propafenone and fluoxetine in extensive metabolisers increases the S-propafenone Cmax and AUC by 39 and 50% and the R-propafenone Cmax and AUC by 71 and 50%. Lower doses of propafenone may therefore be sufficient to achieve the desired therapeutic response.
Close monitoring of the clotting status in patients receiving concomitant oral anticoagulants (e.g. phenprocoumon, warfarin) is recommended as propafenone may enhance the plasma levels of these medicinal products resulting in an increased prothrombin time. Doses of these medicinal products should be adjusted if necessary.
Potential increase in adverse reactions may occur when propafenone is taken in conjunction with local anaesthetics (e.g. pacemaker implantation, surgery or dental work) and other medicinal products which have an inhibitory effect on the heart rate and/or myocardial contractility (e.g. beta blockers, tricyclic antidepressants).
Combination therapy of amiodarone and propafenone hydrochloride can affect conduction and repolarisation and lead to abnormalities that have the potential to be proarrhythmic. Dose adjustments of both compounds based on therapeutic response may be required.
No significant effects on the pharmacokinetics of propafenone or lidocaine have been seen following their concomitant use in patients. However, concomitant use of propafenone hydrochloride and lidocaine have been reported to increase the risks of central nervous system side effects of lidocaine.
Concomitant use of propafenone and phenobarbital and/or rifampicin (CYP3A4 inducers) may reduce the antiarrythmic efficacy of propafenone as a result of a reduction in propafenone plasma levels. Hence, response to propafenone hydrochloride therapy should be monitored during concomitant chronic phenobarbital and/or rifampicin treatment.
Increased plasma levels and/or blood levels of propranolol, metoprolol, desipramine, ciclosporin, theophylline and digoxin have been reported during propafenone therapy. Doses of these medicinal products should be reduced, as appropriate, if signs of overdose are observed.
There are no adequate and well-controlled studies in pregnant women. Propafenone should be used during pregnancy only if the potential benefit justifies the potential risk to the foetus.
Propafenone is known to pass the placental barrier in humans. The concentration of propafenone in the umbilical cord has been reported to be about 30% of that in the maternal blood.
Excretion of propafenone in human breast milk has not been studied. Limited data suggests that propafenone may be excreted in human breast milk. Propafenone should be used with caution in nursing mothers.
Blurred vision, dizziness, fatigue and postural hypotension may affect the patient’s speed of reaction and impair the individual’s ability to operate machinery or motor vehicles.
The most frequent and very common adverse reactions related to propafenone therapy are dizziness, cardiac conduction disorders and palpitations.
The following list displays adverse reactions reported in clinical trials and from post-marketing experience with propafenone.
The reactions considered at least possibly related to propafenone are displayed by system organ class and frequency using the following convention: very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1,000 to <1/100) and not known (adverse reactions from post-marketing experience; cannot be estimated from the available data). Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness when the seriousness could be assessed. The frequencies are based on clinical trial data from propafenone SR. It is expected that the adverse reactions and frequencies for IR formulations would be similar.
Uncommon: Thrombocytopenia
Not Known: Agranulocytosis, Leukopenia, Granulocytopenia
Not Known: Hypersensitivity1
Uncommon: Decreased appetite
Common: Anxiety, Sleep disorders
Uncommon: Nightmare
Not Known: Confusional state
Very common: Dizziness2
Common: Headache, Dysgeusia
Uncommon: Syncope, Ataxia, Paraesthesia
Not Known: Convulsion, Extrapyramidal symptoms, Restlessness
Common: Vision blurred
Uncommon: Vertigo
Very common: Cardiac conduction disorders3, Palpitations
Common: Sinus bradycardia, Bradycardia, Tachycardia, Atrial flutter
Uncommon: Ventricular tachycardia, Arrythmia4
Not Known: Ventricular fibrillation, Cardiac failure5, Heart rate reduced
Uncommon: Hypotension
Not Known: Orthostatic hypotension
Common: Dyspnoea
Common: Abdominal pain, Vomiting, Nausea, Diarrhoea, Constipation, Dry mouth
Uncommon: Abdominal distension, Flatulence
Not Known: Retching, Gastrointestinal disturbance
Common: Hepatic function abnormal6
Not Known: Hepatocellular injury, Cholestasis, Hepatitis, Jaundice
Uncommon: Urticaria, Pruritus, Rash, Erythema
Not Known: Lupus-like syndrome
Uncommon: Erectile dysfunction
Not Known: Sperm count decreased7
Common: Chest pain, Asthenia, Fatigue, Pyrexia
1 May be manifested by cholestasis, blood dyscrasias and rash
2 Excluding vertigo
3 Including sinoatrial block, atrioventricular block and intraventricular block
4 Propafenone may be associated with proarrhythmic effects which manifest as an increase in heart rate (tachycardia) or ventricular fibrillation. Some of these arrhythmias can be life- threatening and may require resuscitation to prevent a potentially fatal outcome
5 An aggravation of preexisting cardiac insufficiency may occur
6 This term covers abnormal liver function tests, such as aspartate aminotransferase increased, alanine aminotransferase increased, gamma-glutamyltransferase increased and blood alkaline phosphatase increased
7 Decreased sperm count is reversible upon discontinuation of propafenone
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