Been there, done that back in February (up to 5.5). I had been alternating 6.5 & 7.0 to keep my INR close to 4.0-4.2. I got bronchitis & a fever and my INR was 5.1 on 2/27. I cut my dose to 3.0 the next day (Monday). On Tuesday 3/1 my INR was 5.5 and my PCP had advised me if it got higher than 5.1 to skip a dose, so I skipped my dose 3/1. On 3/2, I took 6.5 and 6.0 the rest of the week. Retested 3/8 and I was at 3.1.
I thought, fine. So I bumped it back to 6.5, and I was at 5.0 on 3/15. I juggled it a little the next few days and was 3.6 on 3/20. Stayed at 6.0 and was 3.8 on 3/30.
Stayed at 6.0mg for the next 3 weeks and tested 3.5, 3.4. However, I started running intermittent fevers and was 2.9 on 4/23 and 2.8 on 4/26, 2.7 on 5/5. I bumped my dosage back to 6.5 and have been 3.3-3.5 since.
Thank heavens I have my own PT/INR machine!!!!!!!!!!!!!!!!!!!!!!!!!!! I'm not sure I would hold a dose if I was 5.5 again -- probably halve the dose and reduce following doses by 10% and retest in a week.
Marsha (7-28-50), MVP 1990/MVR (St. Jude) & ASD repair 6/24/03 Baylor University Medical Center, Dallas Texas. Hometesting since 11/03, first with ProTime 3, now with INRatio.
John (3-13-46), MV repair 5/10/07, Dallas Presbyterian, port-access incision, Dr. William Ryan. Chordae ruptured 12/05 in car crash.