On tolerability and safety of a maintenance treatment with 6-thioguanine in azathioprine or 6-mercaptopurine intolerant IBD patients

Table 1 Patients’ characteristics

	n = 95 patients
Female:male	58:37 patients
Age (yr)	43 years (range 20–74 yr)
UC:CD	42:53 patients
Duration of IBD at start 6-TG	10.4 yr (SD 9.4 yr)
AZA intolerance	78 patients (82%)
6-MP intolerance	4 patients (4%)
AZA and 6-MP intolerance	13 patients (14%)
AZA or 6-MP rechallenge	36 patients (38%)
Adverse events on AZA or 6MP:	30% gastrointestinal complaints
	20% general malaise
	14% allergic reactions
	10% pancreaticotoxicity
	6% hepatotoxicity
	5% myelotoxicity
	14% rest (e.g., myalgia or alopecia)
6-TG dosage at the start	24.6 mg (range 20-40 mg)

Table 2 Adverse events (n = 26) leading to discontinuation of 6-TG use in 20 patients (AE, adverse event; 6-TG, 6-thioguanine; GI complaints, gastrointestinal complaints)

AE on 6-TG	Frequency (%)	Mean time to AE (d)	Relationship with 6-TG
GI complaints	8/26 (31)	43	Probably 6/8 possibly 2/8
Hepatotoxicity	4/26 (15)	182	Probably 2/4 possibly ¼unrelated 1/4
Myelodepression	1/26 (4)	50	Related
Pancreaticotoxicity	1/26 (4)	103	Possibly
General malaise	4/26 (15)	51	Probably 3/4 possibly ¼
Allergic reaction	1/26 (4)	1	Related
Other AE	7/26 (27)	39	Related 1/7 probably
			2/7 possibly 4/7