Calculation of posterior probability: The posterior odds equal the product of the prior odds and each of the likelihood ratios (2.73x1x3.71x1x1x1=10.1). The posterior probability equals the post erior odds over (1 + the post erior odds), ie, 10.1/ (1+10.1). The probability that ticlopidine was responsible for the aplastic anemia observed in this case is therefore 0.91, a high degree of certainty. ventolin inhalers
Aplastic anemia with ticlopidine is a rare but significant event that supports the recommendation for hematological monitoring during the first three months of therapy. Patients who develop leukopenia must be followed closely until recovery of the white cell count. Febrile illnesses during this period should initially be considered as potentially serious septicemias andtreated promptly and aggressively. A systematic approach is vital to the meaningful analysis and assignment of causality to an adverse event associated with a medication. The Bayesian model for assessing drug versus nondrug etiologies is an especially powerful instrument in establishing a probability of drug causation in suspected adrs.