Overview of haemototoxicity reported in the azathioprine group (n=41)
| Patient ID | TPMT genotype | TPMT activity at baseline (nmol 6-MTG/g Hb/h)* | Adverse event | Maximum 6-TGN level observed after onset of adverse event (pmol/8×108 RBC) | Premature withdrawal | Primary reason for withdrawal |
| 703 | *1/*3A | 19 | Leucopenia | 600 | Yes | Lack of cooperation |
| 706 | *1/*3A | 22 | Leucopenia | 370 | Yes | Intolerable adverse event (leucopenia) |
| 728 | *1/*3A | 19 | Leucopenia/anaemia | 944 | Yes | Intolerable adverse event (leucopenia) |
| 623 | *1/*1 | 52 | Leucopenia | 262 | No | – |
| 734 | *1/*1 | 41 | Leucopenia | 203 | No | – |
| 742 | *1/*1 | 38 | Leucopenia/anaemia | 604 | Yes | Intolerable adverse event (hyperamylasaemia) |
| 831 | *1/*1 | 48 | Leucopenia/anaemia | 978 | Yes | Lack of cooperation |
↵* TPMT activity <23 nmol 6-MTG/g Hb/h is considered an intermediate metaboliser TPMT phenotype.23
Hb, haemoglobin; MTG, methyl-thioguanine; RBC, red blood cell; TGN, thioguanine nucleotides; TPMT, thiopurine methyltransferase.