These cases can be contrasted with cases 2, 3 and 4 whose warfarin therapy was started more than 2 weeks after the initiation of rifampicin. The percentage Protein Tyrosine Kinase inhibitor increase in weekly warfarin dose in these patients was not as dramatic (16.0 %, −4.8 % and 15.3 % respectively). However, exceptions to this observation exist such as that seen in case 8. Case
8, a 38 year-old female on warfarin therapy due to pulmonary embolism and selleck screening library DVT, was on rifampicin treatment for more than two weeks before warfarin was started, and yet showed a 440.9 % increase in weekly warfarin dose from the initial starting dose. Compared to cases 2, 3 and 4, described above, the timing of warfarin initiation in relation to the commencement of rifampicin therapy in case 8 should have resulted in a less dramatic percent increase in the warfarin dose. Clinicians should therefore anticipate a large percentage increase in weekly warfarin dose and should frequently assess patients whose warfarin therapy is started simultaneously or within 2 weeks of initiating rifampicin. Empiric dose adjustments based on the start date of rifampicin are not recommended. Table 1 also highlights the potential impact of other concomitant interacting medications as several of the patients were
on antibiotics Saracatinib purchase (amoxicillin/clavulanic acid, sulfamethoxazole/trimethoprim), cardiovascular medications (furosemide), pain medications (paracetamol, ibuprofen) and mental health medications known to alter the response to warfarin [30–36]. Without an appropriate
control group, it is difficult to determine Fossariinae how these medications might have impacted the response to the drug interaction between warfarin and rifampicin. In addition, many of these patients had other co-morbid conditions, which can increase the complexity of warfarin therapy. Such patients are also more likely to have unpredictable variations in their overall health status and concurrent medications that may potentially interact with warfarin, requiring more intense monitoring of INR and adverse drug reactions [37]. This study possesses certain key limitations largely related to its retrospective nature and reliance on data obtained during the routine clinical encounter. While the study was able to definitively determine the adherence to warfarin, adherence to other medications was based purely on patient self-report. With the case series design of this investigation, the ability to form conclusive recommendations on the dosing of rifampicin in different populations is difficult as a comparison control group is lacking and the patient population is small. 5 Conclusion With access to healthcare infrastructure in sub-Saharan Africa continuing to grow, there is an emerging need for contextualized research describing the unique dynamics and responses to therapy in these populations.