Plasma Digoxin Concentration Fluctuations Associated with Timing of Plasma Sampling and Amiodarone Administration

DeVore, Kelli J; Hobbs, Ryan A.

doi:10.1592/phco.27.3.472

Cited by 14 publications

(6 citation statements)

References 8 publications

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“…5 Digoxin therapy should be adjusted based on any signs and symptoms of digoxin toxicity. 26 Another potential interaction occurred between warfarin and amiodarone, with the potential for anticoagulant effects due to amiodarone and higher risk of hemorrhage. In fact, the warfarin dose had to be modified.…”

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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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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“…However, clinicians should be aware that digoxin plasma concen-trations may not correlate with digoxin tissue concentrations in this setting. When a loading dose of oral amiodarone is required in a patient receiving digoxin, the digoxin dosage should first be reduced, and digoxin therapy should be adjusted based on any signs and symptoms of digoxin toxicity [ 22 ]. This approach also applies to theophylline when erythromycin is added to the regimen.…”

Section: Purpose Of Therapeutic Drug Monitoringmentioning

confidence: 99%

Overview of Therapeutic Drug Monitoring

Kang

Lee

2009

Korean J Intern Med

471

347

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Therapeutic drug monitoring (TDM) is the clinical practice of measuring specific drugs at designated intervals to maintain a constant concentration in a patient's bloodstream, thereby optimizing individual dosage regimens. It is unnecessary to employ TDM for the majority of medications, and it is used mainly for monitoring drugs with narrow therapeutic ranges, drugs with marked pharmacokinetic variability, medications for which target concentrations are difficult to monitor, and drugs known to cause therapeutic and adverse effects. The process of TDM is predicated on the assumption that there is a definable relationship between dose and plasma or blood drug concentration, and between concentration and therapeutic effects. TDM begins when the drug is first prescribed, and involves determining an initial dosage regimen appropriate for the clinical condition and such patient characteristics as age, weight, organ function, and concomitant drug therapy. When interpreting concentration measurements, factors that need to be considered include the sampling time in relation to drug dose, dosage history, patient response, and the desired medicinal targets. The goal of TDM is to use appropriate concentrations of difficult-to-manage medications to optimize clinical outcomes in patients in various clinical situations.

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“…Amiodarone also has been implicated in reducing the tissue protein binding of digoxin, thereby reducing the volume of distribution of digoxin and causing an increase in digoxin serum concentrations and the risk for toxicity [9]. However, measured digoxin serum concentrations were not present in our patient and the patient was not on amiodarone the first time she demonstrated altered mental status after receiving digoxin.…”

Section: Discussionmentioning

confidence: 55%