Question explored with the scientific record
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- 1 What is the highly toxic drug they give for intractable afib
- 2 How long does it take to workWhat is the highly toxic drug they give for intractable a fib
- 3 If it hasnt worked after a week or two is it best to stop?How long does it take to workWhat is the highly toxic drug they give for intractable a fib
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If it hasnt worked after a week or two is it best to stop?How long does it take to workWhat is the highly toxic drug they give for intractable a fib
Don't stop amiodarone at two weeks if it's working. Stop it if you're in the 1 to 21 in 100 who can't tolerate it.
On timing: for converting a rhythm, IV amiodarone works over hours, not minutes. In a randomized trial adding ranolazine to IV amiodarone cut time to conversion to 10.2 hours, from 13.3 hours [1]. For keeping rhythm after conversion, amiodarone is a long game: it held sinus rhythm in 53 to 80 in 100 patients over 15 to 27 months in the 1995 review [2]. So a week or two is too early to judge maintenance. The drug accumulates in tissue and its effects build slowly.
If you're asking about stopping because of side effects rather than lack of effect, that's a different question with a real answer. Intolerable side effects hit 1 to 21 in 100 patients in the trials reviewed [2]. Permanent discontinuation in an AF registry ran 37.7 in 100, with thyroid problems the leading side effect and physician judgment the other big driver [7]. The toxicities are cumulative: lung scarring, thyroid, liver, nerve, skin, eyes [3][6][4][5]. The longer you take it, the more it builds up and the higher the risk.
| What you're treating | Time to judge it |
|---|---|
| Converting a rhythm now | Hours to days (10 to 13 h IV) [1] |
| Keeping rhythm long term | Months, not weeks [2] |
| Tolerability | Continuous; thyroid first [7] |
My call: don't stop at two weeks for "it hasn't worked" if the goal is rhythm maintenance, because that clock hasn't run. Do push for a serious conversation if you feel terrible, and get your thyroid checked. Confidence: moderate, because the records don't isolate your exact scenario.
Sources used 7
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Novel Use of Ranolazine as an Antiarrhythmic Agent in Atrial Fibrillation
A narrative review synthesizing the pharmacology of ranolazine and clinical trial evidence for its use as an antiarrhythmic in atrial fibrillation, including monotherapy and adjunctive therapy, and its potential role in post-cardiothoracic surgery AF.
DOI: 10.1177/1060028016673073 -
Amiodarone for the Maintenance of Sinus Rhythm in Patients with Atrial Fibrillation
In this review, amiodarone maintained normal sinus rhythm in 53-80% of patients with atrial fibrillation refractory to conventional agents and appeared equal or superior to class IA drugs, but toxicity and the lack of large randomized trials temper its use.
DOI: 10.1177/106002809502900609 -
Amiodarone: Individualizing Dosage with Serum Concentrations
This study investigates the pharmacokinetics and clinical efficacy of amiodarone, emphasizing the importance of individualizing dosage based on serum concentrations to optimize therapeutic outcomes and minimize adverse effects.
DOI: 10.1111/j.1540-8159.1983.tb04475.x -
Akinesia and amiodarone therapy
This study reports a case of akinesia as an unusual side effect of amiodarone therapy in a patient with liver cirrhosis, highlighting the need for careful monitoring of neurological effects associated with the drug.
DOI: 10.1016/s0167-5273(96)02891-4 -
Prediction of the dose range for adverse neurological effects of amiodarone in patients from an in vitro toxicity test by in vitro–in vivo extrapolation
PBPK-based IVIVE of in vitro brain toxicity data predicts human doses of amiodarone that could cause adverse neurological effects, aligning with clinical neurotoxicity reports and supporting choline acetyltransferase (ChAT) inhibition as a mechanistic link.
DOI: 10.1007/s00204-021-02989-2 -
Amiodarone and pulmonary fibrosis
This study investigates the potential causal link between amiodarone administration and the development of pulmonary fibrosis in five patients, suggesting a hypersensitivity mechanism.
DOI: 10.1007/BF00542206 -
P1900Amiodarone treatment duration and reasons for permanent drug discontinuation in patients with atrial fibrillation
Permanent amiodarone discontinuation occurred in 37.7% of AF patients, was associated with physician's decision and side effects, with thyroid dysfunction most common and no pulmonary toxicity or proarrhythmia.
DOI: 10.1093/eurheartj/ehz748.0647