Characteristics of the amiodarone–warfarin interaction during long-term follow-up

Lu, Yun; Won, Katie; Nelson, Brenda J.; Qi, Dongfeng; Rausch, Douglas; Asinger, Richard W.

doi:10.2146/ajhp060415

Cited by 37 publications

(25 citation statements)

References 18 publications

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“…This interaction has been identified years ago (first report 1988) and is well described in the literature (especially for warfarin) [19,33,34]. A close monitoring is recommended when this drug is administered with acenocoumarol, and given the long half-life of amiodarone, caution should also be taken several weeks after the treatment has been interrupted.…”

Section: Discussionmentioning

confidence: 89%

Identification and weighting of the most critical “real-life” drug–drug interactions with acenocoumarol in a tertiary care hospital

Gschwind

Rollason

Lovis

et al. 2012

Eur J Clin Pharmacol

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Purpose The objective of this study was to identify the most clinically relevant drug-drug interactions (DDIs) at risk of affecting acenocoumarol safety in our tertiary care university hospital, a 2,000 bed institution. Methods We identified DDIs occurring with acenocoumarol by combining two different sources of information: a 1-year retrospective analysis of acenocoumarol prescriptions and comedications from our Computerized Physician Order Entry (CPOE) system (n = 2,439 hospitalizations) and a retrospective study of clinical pharmacology consultations involving acenocoumarol over the past 14 years (1994-2007) (n = 407). We classified these DDIs using an original risk-analysis method. A criticality index was calculated for each associated drug by multiplying three scores based on mechanism of interaction, involvement in a supratherapeutic international normalized ratio (INR) (≥ 6) and involvement in a severe bleeding.Results One hundred and twenty-six DDIs were identified and weighted. Twenty-eight drugs had a criticality index ≥ 20 and were therefore considered at high risk for interacting with acenocoumarol by increasing its effect: 75% of these drugs involved a pharmacokinetic mechanism and 14 % a pharmacodynamic mechanism. An unknown mechanism of interaction was involved in 11 % of drugs. Conclusion Twenty-eight specific drugs were identified as being at high risk for interacting with acenocoumarol in our hospital using an original risk-analysis method. Most analyzed drugs interact with acenocoumarol via a pharmacokinetic mechanism. Actions such as the implementation of alerts in our CPOE system should be specifically developed for these drugs.

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Section: Discussionmentioning

confidence: 89%

Identification and weighting of the most critical “real-life” drug–drug interactions with acenocoumarol in a tertiary care hospital

Gschwind

Rollason

Lovis

et al. 2012

Eur J Clin Pharmacol

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“…In fact, the warfarin dose had to be modified. 24,[27][28][29] Considering the therapeutic tools available to healthcare professionals, physicians and pharmacists in particular need to be alert regarding detection of clinically significant drug-drug interactions. Cahill 11 reported that, because of the close links between physicians and pharmacists, teamwork for revision and intervention within the context of drug-drug interactions is required.…”

Section: Discussionmentioning

confidence: 99%

Frequency of potential interactions between drugs in medical prescriptions in a city in southern Brazil

Bleich¹,

Bleich

Chiamulera

et al. 2009

Sao Paulo Med. J.

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CONTEXT AND OBJECTIVE: Drug interactions form part of current clinical practice and they affect between 3 and 5% of polypharmacy patients. The aim of this study was to identify the frequency of potential drug-drug interactions in prescriptions for adult and elderly patients. METHODS: Stratified cluster sampling, proportional to the total number of homes in the housing project, was used. The sample consisted of 95 homes and 96 male or female patients aged 19 or over, with medical prescriptions for at least two pharmaceutical drugs. Interactions were identified using DrugDigest, Medscape and Micromedex softwares. TYPE OF STUDY AND SETTING: RESULTS:Most of the patients were female (69.8%), married (59.4%) and in the age group of 60 years or over (56.3%), with an income less than or equal to three minimum monthly salaries (81.3%) and less than eight years of schooling (69.8%); 90.6% of the patients were living with another person.The total number of pharmaceutical drugs was 406 (average of 4.2 medications per patient). The drugs most prescribed were antihypertensives (47.5%).The frequency of drug interactions was 66.6%. Among the 154 potential drug interactions, 4.6% were classified as major, 65.6% as moderate and 20.1% as minor. CONCLUSION:The high frequency of drug prescriptions with a potential for differentiated interactions indicates a situation that has so far been little explored, albeit a reality in household surveys.RESUMO CONTEXTO E OBJETIVO: As interações medicamentosas fazem parte da prática corrente na clínica médica e a sua incidência oscila entre 3% e 5% nos pacientes fazendo uso da polifarmácia. O objetivo do estudo foi identificar a frequência de interações droga-droga potenciais em prescrições de pacientes adultos e idosos. MÉTODO: A amostra foi por conglomerado e estratificada, proporcional ao total de residências no conjunto habitacional, constituída de 95 residências, com 96 pacientes de 19 anos ou mais, sexo feminino e masculino, com prescrição de no mínimo duas especialidades farmacêuticas. As interações foram identificadas de acordo com os softwares DrugDigest, Medscape, Micromedex. TIPO DE ESTUDO E LOCAL: RESULTADOS:A maioria dos pacientes pertencia ao gênero feminino (69,8%), em situação conjugal casada (59,4%), com renda menor ou igual a três salários mínimos (81,3%), faixa etária 60 anos ou mais (56,3%) e 8 anos ou menos de estudo (69,8%) com 90,6% dos pacientes moravam com mais outra pessoa. O total de especialidades farmacêuticas foi de 406, correspondendo a uma média de 4,2 medicamentos por paciente. Os fármacos mais prescritos foram os anti-hipertensivos (47,5%). A frequência de interações medicamentosas foi de 66,6%. Dentre as 154 interações medicamentosas potenciais, 4,6% foram classificadas como maior e 65,6% como moderada e 20,1% como menor.CONCLUSÃO: A alta frequência de prescrições de drogas com potencial de interações diferenciado indica uma situação ainda pouco explorada, mas real em pesquisa domiciliar.

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“…Although the pharmacokinetics of warfarin are unchanged in thyrotoxicosis, the rate of degradation of the coagulation factors dependent on vitamin K is increased in this setting, which results in potentiation of warfarin effects. Therefore, an unexplained change in warfarin sensitivity requiring a decrease in dosage should lead the treating physician to suspect hyperthyroidism [39,40]. AMIO per se can affect warfarin metabolism irrespective of thyrotoxicosis; the presence of concomitant genetic abnormalities affecting warfarin metabolism (CYP2C9*3/*3, VKORC1*3/*3) may further expose the patient to the risk of overtreatment [41].…”

Section: Clinical Features Of Aitmentioning

confidence: 99%

“…Uważa się, że niewyjaśniona zwiększona wrażliwość na warfarynę oraz konieczność zmniejszenia jej dawki pozwala podejrzewać nadczynność tarczycy [39,40]. Amiodaron może wpływać na metabolizm warfaryny per se, niezależnie od nadczynności tarczycy; obecność zaburzeń genetycznych wpływających na metabolizm warfaryny (CYP2C9*3/*3, VKORC1*3/*3) może dodatkowo zwiększać ryzyko przedawkowania leku [41].…”

Section: Szkolenie Podyplomoweunclassified

Amiodaron i tarczyca

Jabrocka‐Hybel

Bednarczuk

Bartalena

et al. 2015

Endokrynologia Polska

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Amiodarone, a benzofuranic iodine-rich antiarrhythmic drug, causes thyroid dysfunction in 15-20% of cases. Amiodarone can cause both hypothyroidism (AIH, amiodarone-induced hypothyroidism) and thyrotoxicosis (AIT, amiodarone-induced thyrotoxicosis). AIH is treated by L-thyroxin replacement and does not need amiodarone discontinuation. There are two main forms of AIT: type 1, a form of true iodineinduced hyperthyroidism; and type 2, a drug-induced destructive thyroiditis. However, mixed/indefinite forms exist, contributed to by both pathogenic mechanisms. Type 1 AIT usually occurs in diseased thyroid glands, whereas type 2 AIT develops in substantially normal thyroid glands. Thioamides represent the first-line treatment for type 1 AIT, but iodine-replete glands are poorly responsive; sodium/ /potassium perchlorate, by inhibiting thyroidal iodine uptake, may increase the response to thioamides. Type 2 AIT is best treated by oral glucocorticoids. Response depends on thyroid volume and severity of thyrotoxicosis. Mixed/indefinite forms may require a combination of thioamides, potassium perchlorate, and steroids. Radioiodine treatment is usually not feasible because amiodarone-related iodine load decreases thyroidal radioiodine uptake. Thyroidectomy represents an important and helpful option in cases resistant to medical therapy. Surgery performed by a skilled surgeon may represent an emergent treatment in patients who have severe cardiac dysfunction. StreszczenieLek antyarytmiczny -amiodaron, pochodna benzofuranu bogata w jod, wywołuje zaburzenia funkcji tarczycy w 15-20% przypadków. Amiodaron może powodować niedoczynność tarczycy (AIH) oraz nadczynność tarczycy (AIT). AIH jest leczona substytucyjnie lewotyroksyną, w jej przypadku nie jest konieczne odstawienie amiodaronu. Nadczynność tarczycy indukowaną amiodaronem dzielimy na dwa typy: typ 1 -nadczynność tarczycy związana z nadmierną produkcją hormonów tarczycowych, oraz typ 2, w której dominuje proces zapalenia tarczycy związanego z rozpadem gruczołu. Wyróżnia się również typ mieszany/nieokreślony, w którego patomechanizmie udział biorą oba powyżej opisane mechanizmy. Typ 1 AIT występuje zwykle na podłożu wcześniej występującej choroby tarczycy, zaś typ 2 w pierwotnie zdrowym gruczole tarczowym. Tionamidy są lekiem pierwszego rzutu w leczeniu typu 1 AIT, nadchloran sodowy/ /potasowy poprzez hamowanie wychwytu jodu może zwiększać odpowiedź na tionamidy. AIT typu 2 jest leczone głównie z zastosowaniem glikokortykosteroidów. Odpowiedź na leczenie zależy od wielkości gruczołu tarczowego i ciężkości tyreotoksykozy. Postaci mieszane mogą wymagać zastosowania złożonej terapii z użyciem tionamidów, nadchloranu sodowego/potasowego oraz steroidów. Leczenie radiojodem często jest niemożliwe z powodu zmniejszonego wychwytu jodu u pacjentów wcześniej leczonych amiodaronem. Zabieg usunięcia tarczycy jest bardzo pomocną formą leczenia nadczynności tarczycy indukowanej jodem, szczególnie w przypadkach opornych na leczenie farmakologiczne. Tyroidektomia wykonana przez do...

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Characteristics of the amiodarone–warfarin interaction during long-term follow-up

Cited by 37 publications

References 18 publications

Identification and weighting of the most critical “real-life” drug–drug interactions with acenocoumarol in a tertiary care hospital

Identification and weighting of the most critical “real-life” drug–drug interactions with acenocoumarol in a tertiary care hospital

Frequency of potential interactions between drugs in medical prescriptions in a city in southern Brazil

Amiodaron i tarczyca

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