Graves’ Disease and Treatment Effects on Warfarin Anticoagulation

Table 4

Response to warfarin after levothyroxine initiation.

Days since levothyroxine initiation	Warfarin dose; (mg/day)^a	INR^b,c	New warfarin^a dose; (mg/day)	Levothyroxine; (75 mcg/day)	TSH^d; (𝜇IU/mL)	Free T4^e; (ng/dL)	Free T3^f; (pg/mL)
1	5: MTWThSSu; 7.5: F	3.2	No change	Not taking
13	5: MTWThSSu; 7.5: F	2.2	No change	Taking since last visit	3.63	0.7
73	5: MTWThSSu; 7.5: F	1.5	No change	Not taking for 2 weeks	<0.006	1.49
86	5: MTWThSSu; 7.5: F	2.8	No change	Only taking for 1week	<0.006	2.11	4.9
133	5: MTWThSSu; 7.5: F	2.5	No change	Had not taken since last visit	0.008	1.40	4.2

aLetters are abbreviations for days of the week: Monday (M), Tuesday (T), Wednesday (W), Thursday (R), Friday (F), Saturday (S), and Sunday (Su).
^bINR: international normalized ratio, goals 2-3.
^cINR obtained via point of care testing with Roche Diagnostics CoaguChek XS.
^dTSH: thyroid stimulating hormone, reference range 0.450–4.500.
^eFree T₄: free thyroxine, reference range 0.82–1.77.
^fFree T₃: free triiodothyronine, reference range 2–4.4.