On suicidal pacts

I have just seen an elderly woman, aged 77 or more, who has survived the death of her husband (by suffocation/asphyxia?). It appears that she also tried to take her life by swallowing a considerable amount of benzodiazepines (the public in general still believe that they are narcotics and continue using this term). Had I been working in England I would have had to call for a MHA assessment with another doctor (her GP) and an ASW (approved social worker); the whole process would have complicated the situation tremendously. As I now work in Spain, I took the unilateral decision of admitting her into hospital involuntarily (for more information of the equivalent of the Mental Health Act in Spain, click here). However, was it legal to do this or, even better, was it ethical? I really do not know... she appeared to be compos mentis. On the other hand, I believe that it was the only sensible thing to do... the risk of her taking her life was too high.