When should I increase rifabutin?

Hi everyone

I was prescribed 300 mg rifabutin (150 in the morning, 150 at night.) I started with 150 mg for a few days. After how many days should I increase to 300 mg? Many people told me to take it slow but I've been on 150 mg for 4 days now and I haven't herxed that much as I was expecting so I was wondering is it time to titrate up or wait a few more days.