Table 3.
VPA C/D ratio in Case 2.
| Day1 | Formulation | VPA dose1 (mg/day) | Concentration (μg/mL) | C/D ratio | C/D ratio × 10002 |
|---|---|---|---|---|---|
| All 10 VPA concentrations (C/D ratio × 1000: mean ± SD = 25 ± 5.6, range = 17–33) | |||||
| 8 therapeutic2 VPA concentrations (C/D ratio × 1000: mean ± SD = 24 ± 5.6, range = 17–33) | |||||
| 53 | ECDVNa | 1500 | 39 | 0.026 | 26 |
| 83 | ECDVNa | 1500 | 49 | 0.033 | 33 |
| 144 | ECDVNa | 2500 | 61 | 0.024 | 24 |
| 205 | ECDVNa | 2500 | 75 | 0.030 | 30 |
| 236 | ECDVNa | 2500 | 82 | 0.033 | 33 |
| 297 | ECDVNa | 3000 | 77 | 0.026 | 26 |
| 367 | Concentrate | 3500 | 72 | 0.020 | 20 |
| 417 | Concentrate | 3500 | 78 | 0.022 | 22 |
| 488 | Concentrate | 4000 | 73 | 0.018 | 18 |
| 559 | ECDVNa | 4000 | 67 | 0.017 | 17 |
C/D: concentration-to-dose; ECDVNa: enterocoated divalproex sodium; VPA: valproic acid.
1The Pearson correlation between day of admission and VPA dose was r = 0.97 (p < 0.001); VPA dose remained significant in a partial correlation while controlling for VPA concentration: r = 0.96 (p < 0.001). This is compatible with a progressive autoinduction indicating, at least with dose range, that it was necessary to increase the dose as the duration lengthened.
250–125 μg/mL concentrations are considered therapeutic concentrations. As this patient has 2 nontherapeutic concentrations, it would be better to compare a priori with other patients using only the VPA therapeutic concentrations. In reality, eliminating the first 2 VPA concentrations, which were subtherapeutic, made almost no difference.
3Other scheduled oral medications included asenapine 10 mg/day, naproxen 1000 mg/day, omeprazole 20 mg/day, trimethoprim/sulfamethoxazole 1600/320 mg/day (for skin breakdown over swollen lower extremities), and trazodone 100 mg/day.
4Other scheduled oral medications included asenapine 15 mg/day, gabapentin 900 mg/day, lisinopril 10 mg/day, meloxicam 15 mg/day, metoprolol 50 mg/day, omeprazole 20 mg/day, trimethoprim/sulfamethoxazole 1600/320 mg/day (for skin breakdown over swollen lower extremities), tramadol 150 mg/day, and trazodone 150 mg/day.
5Other scheduled oral medications included asenapine 15 mg/day, gabapentin 900 mg/day, lisinopril 10 mg/day, meloxicam 15 mg/day, metoprolol 50 mg/day, omeprazole 20 mg/day, tramadol 150 mg/day, and trazodone 150 mg/day.
6Other scheduled oral medications included asenapine 15 mg/day, furosemide 40 mg/day, gabapentin 900 mg/day, lisinopril 10 mg/day, metoprolol 50 mg/day, omeprazole 20 mg/day, tramadol 150 mg/day, and trazodone 150 mg/day.
7Other scheduled oral medications included asenapine 15 mg/day, furosemide 20 mg/day, gabapentin 1200 mg/day, lisinopril 10 mg/day, metoprolol 50 mg/day, omeprazole 20 mg/day, tramadol 200 mg/day, and trazodone 150 mg/day.
8Other scheduled oral medications included asenapine 15 mg/day, furosemide 20 mg/day, gabapentin 1200 mg/day, metoprolol 50 mg/day, omeprazole 20 mg/day, tramadol 200 mg/day, and trazodone 150 mg/day.
9Other scheduled oral medications included asenapine 15 mg/day, furosemide 20 mg/day, gabapentin 1200 mg/day, metoprolol 50 mg/day, omeprazole 20 mg/day, polyethylene glycol 17 g/day, tramadol 200 mg/day, and trazodone 150 mg/day.