Table 1 Description of the severity of phototoxicity reactions as recorded in the trials

0 None

No symptoms.

1–3 Mild

The reaction is transient and easily tolerated, not requiring any treatment.

4–6 Moderate

The reaction caused discomfort and interrupted usual activities. Some form of treatment was required.

7–9 Severe

The reaction caused considerable interference with usual activities and may have been incapacitating, requiring treatment.

10 Worst Imaginable

The reaction causes extensive interference with usual activities and is incapacitating, requiring treatment and/or hospitalisation.