Antidepressant-Warfarin Interaction and Associated Gastrointestinal Bleeding Risk in a Case-Control Study

Bleeding is the most common and worrisome adverse effect of warfarin therapy. One of the factors that might increase bleeding risk is initiation of interacting drugs that potentiate warfarin. We sought to evaluate whether initiation of an antidepressant increases the risk of hospitalization for gastrointestinal bleeding in warfarin users.Medicaid claims data (1999-2005) were used to perform an observational case-control study nested within person-time exposed to warfarin in those ≥18 years. In total, 430,455 warfarin users contributed 407,370 person-years of warfarin use. The incidence rate of hospitalization for GI bleeding among warfarin users was 4.48 per 100 person-years (95% CI, 4.42-4.55). Each gastrointestinal bleeding cases was matched to 50 controls based on index date and state. Warfarin users had an increased odds ratio of gastrointestinal bleeding upon initiation of citalopram (OR = 1.73 [95% CI, 1.25-2.38]), fluoxetine (OR = 1.63 [95% CI, 1.11-2.38]), paroxetine (OR = 1.64 [95% CI, 1.27-2.12]), amitriptyline (OR = 1.47 [95% CI, 1.02-2.11]). Also mirtazapine, which is not believed to interact with warfarin, increased the risk of GI bleeding (OR = 1.75 [95% CI, 1.30-2.35]).Warfarin users who initiated citalopram, fluoxetine, paroxetine, amitriptyline, or mirtazapine had an increased risk of hospitalization for gastrointestinal bleeding. However, the elevated risk with mirtazapine suggests that a drug-drug interaction may not have been responsible for all of the observed increased risk

Interações medicamentosas: fundamentos para a pratica clínica da enfermagem Drugs interactions: fundamental aspects for clinical practice nursing

O fenômeno das interações medicamentosas constitui na atualidade um dos temas mais importantes da farmacologia, para a prática clínica dos profissionais da saúde. O uso concomitante de vários medicamentos, enquanto estratégia terapêutica, e o crescente número destes agentes no mercado são alguns dos fatores que contribuem para ampliar os efeitos benéficos da terapia, mas que também possibilitam a interferência mútua de ações farmacológicas podendo resultar em alterações dos efeitos desejados. Este artigo, de revisão, tem por objetivos rever os princípios farmacológicos relacionados aos mecanismos das interações medicamentosas; descrever as classes dos medicamentos interativos, os grupos de pacientes expostos ao risco e sugerir medidas práticas para a equipe de enfermagem, no intuito de prevenir a ocorrência de reações adversas decorrentes de interações fortuitas.<br>Nowadays drugs interactions constitute one the most important subjects of pharmacological for clinical practive of health professionals. The concomitant use of many drugs as therapeutic strategy and the growing number of agents available contribute to enlarge the benefical effects of therapy. Besides, these factors can also permit the mutual interference of pharmacological actions that result in alteractions of therapeutics effects. The aim of this article is to review the principles pharmacological related to the mechanisms of drugs interactions, to describe the types of interactive drugs; the groups of risk patients and to suggest specific nursing interventions aiming the prevention of occurrence of adverse reactions from accidental interactions

Protocol of the impact of alternative social assistance disbursement on drug-related harm (TASA) study : a randomized controlled trial to evaluate changes to payment timing and frequency among people who use illicit drugs

BACKGROUND: Government social assistance payments seek to alleviate poverty and address survival needs, but their monthly disbursement may cue increases in illicit drug use. This cue may be magnified when assistance is disbursed simultaneously across the population. Synchronized payments have been linked to escalations in drug use and unintended but severe drug-related harms, including overdose, as well as spikes in demand for health, social, financial and police services. METHODS/DESIGN: The TASA study examines whether changing payment timing and frequency can mitigate drug-related harm associated with synchronized social assistance disbursement. The study is a parallel arm multi-group randomized controlled trial in which 273 participants are randomly allocated for six assistance cycles to a control or one of two intervention arms on a 1:1:1 basis. Intervention arm participants receive their payments: (1) monthly; or (2) semi-monthly, in each case on days that are not during the week when cheques are normally issued. The study partners with a community-based credit union that has developed a system to vary social assistance payment timing. The primary outcome is a 40 % increase in drug use during the 3 days beginning with cheque issue day compared to other days of the month. Bi-weekly follow-up interviews collect participant information on this and secondary outcomes of interest, including drug-related harm (e.g. non-fatal overdose), exposure to violence and health service utilization. Self-reported data will be supplemented with participant information from health, financial, police and government administrative databases. A longitudinal, nested, qualitative parallel process evaluation explores participant experiences, and a cost-effectiveness evaluation of different disbursement scenarios will be undertaken. Outcomes will be compared between control and intervention arms to identify the impacts of alternative disbursement schedules on drug-related harm resulting from synchronized income assistance. DISCUSSION: This structural RCT benefits from strong community partnerships, highly detailed outcome measurement, robust methods of randomization and data triangulation with third party administrative databases. The study will provide evidence regarding the potential importance of social assistance program design as a lever to support population health outcomes and service provision for populations with a high prevalence of substance use.Arts, Faculty ofMedicine, Faculty ofOther UBCNon UBCEmergency Medicine, Department ofPopulation and Public Health (SPPH), School ofSociology, Department ofReviewedFacultyUnknow