What are the recommendations for patients who receive Warfarin and are also taking Rifampicin? Care should be taken if Warfarin is co-administered...

What are the recommendations for patients who receive Warfarin and are also taking Rifampicin?

Care should be taken if Warfarin is co-administered with a CYP450 enzyme inducer, such as rifampicin, as this may lead to increased metabolism and decreased efficacy of Warfarin.
When adding or withdrawing rifampicin therapy in a patient using Warfarin, monitor the prothrombin time (PT) and the international normalized ratio (INR) frequently.
High doses of Warfarin (20 mg/day or more) may be necessary to maintain adequate anticoagulation when used with rifampicin.
A 50% reduction in the Warfarin dose should be considered within 1 to 2 weeks after discontinuation of rifampicin.
Patients should be monitored for signs and symptoms of subtherapeutic anticoagulation.
a) Only statements I, II, and III are correct.
b) Only statements II, III, and IV are correct.
c) Only statements III, IV, and V are correct.
d) All statements are correct.