Number and percentage of drug names subject to changes within 1998–2016 PCA data when compared with the current BNF by Chapter
| Current chapter code (name) | Name/spelling change | No change | No match | Grand total | |||
| n | % | n | % | n | % | n | |
| 1 (Gastrointestinal system) | 0.0 | 1041 | 99.1 | 9 | 0.9 | 1050 | |
| 2 (Cardiovascular system) | 177 | 7.2 | 2278 | 92.5 | 8 | 0.3 | 2463 |
| 3 (Respiratory system) | 238 | 20.8 | 893 | 78.0 | 14 | 1.2 | 1145 |
| 4 (Central nervous system) | 341 | 8.8 | 3535 | 90.7 | 21 | 0.5 | 3897 |
| 5 (Infections) | 119 | 9.1 | 1184 | 90.7 | 3 | 0.2 | 1306 |
| 6 (Endocrine system) | 203 | 13.2 | 1320 | 86.0 | 11 | 0.7 | 1534 |
| 7 (Obstetrics, gynaecology and urinary tract disorders) | 4 | 0.7 | 508 | 90.7 | 48 | 8.6 | 560 |
| 8 (Malignant disease and immunosuppression) | 2 | 0.3 | 538 | 91.8 | 46 | 7.8 | 586 |
| 9 (Nutrition and blood) | 210 | 4.0 | 4281 | 81.3 | 776 | 14.7 | 5267 |
| 10 (Musculoskeletal and joint diseases) | 89 | 8.5 | 956 | 90.8 | 8 | 0.8 | 1053 |
| 11 (Eye) | 18 | 3.0% | 532 | 87.2 | 60 | 9.8 | 610 |
| 12 (Ear, nose and oropharynx) | 16 | 3.4 | 373 | 78.5 | 86 | 18.1 | 475 |
| 13 (Skin) | 22 | 1.1 | 1772 | 89.5 | 186 | 9.4 | 1980 |
| 14 (Immunological products and vaccines) | 7 | 3.0 | 198 | 85.0 | 28 | 12.0 | 233 |
| 15 (Anaesthesia) | 15 | 5.2 | 229 | 78.7 | 47 | 16.2 | 291 |
| Grand total | 1461 | 6.5 | 19 638 | 87.5 | 1351 | 6.0 | 22 450 |
These name changes include changes in word order, spacing, capitalisation, abbreviation, punctuation (eg, “Califig_(California Syr Of Figs)”/“Califig_California Syr Of Figs”), spelling (eg, “Sulphate”/“Sulfate”), brand name (eg, “Laxoberal_Liq”/“Dulcolax Pico_Liq”) and formulation (eg, “Castor Oil”/“Castor Oil_Liq”). The total count of drug names is reduced compared with table 1 because the same drugs can appear over multiple years but only rarely in multiple Chapters.
BNF, British National Formulary; PCA, prescription cost analysis.