Table 4.
Median (25% quartile–75% quartile) of urinary excretion (UE, µmol) and 36 h urinary recovery (UR, % of the dose) of methotrexate (MTX) and 7-hydroxymethotrexate (7-OHMTX) in psoriatic patients on low-dose oral MTX. The weekly dose was divided into three aliquots of either 2.5 mg (5.5 µmol) or 5 mg (11 µmol) given at 12 h intervals. Urine collection was performed over 12 h following each of the three doses at weeks 1 and 13.
| Week 1 | Week 13 | |||
|---|---|---|---|---|
| Dose | 2.5 mg | 5 mg | 2.5 mg | 5 mg |
| UE(0,12 h) MTX (µmol) | 3.7 (3.6–4.2) | 7.4 (7.2–8.3) | 3.4 (2.9–4.7) | 8.0 (5.6–8.8) |
| UE(12,24 h) | 3.1 (2.6–3.9) | 7.0 (6.1–7.4) | 3.2 (2.1–3.7) | 6.7 (5.3–8.0) |
| UE(24,36 h) | 4.1 (3.2–5.2) | 7.2 (6.2–8.8) | 4.3 (3.8–5.3) | 8.7 (7.5–10.5) |
| UE(0,12 h) 7-OHMTX (µmol) | 0.06 (0.04–0.08) | 0.10 (0.9–0.17) | 0.08 (0.06–0.12) | 0.12 (0.08–0.18) |
| UE(12,24 h) | 0.08 (0.05–0.12) | 0.18 (0.10–0.24) | 0.08 (0.07–0.17) | 0.19 (0.11–0.30) |
| UE(24,36 h) | 0.20 (0.13–0.26) | 0.39 (0.26–0.52) | 0.19 (0.17–0.20) | 0.26 (0.15–0.33) |
| UR(0,36 h) MTX (%) | 69.3 (60.1–76.7) | 63.2 (59.1–73.6) | 58.0 (45.6–76.7) | 73.2 (61.3–84.2) |
| UR(0,36 h) 7-OH MTX (%) | 2.4 (1.4–2.8) | 2.2 (0.9–2.5) | 2.6 (1.8–3.1) | 1.7 (1.2–2.0) |