Sir,- In my role as BDJ Adviser on Abstracts, I recently drew attention to the first reports of the serious complication of intracranial hypertension arising from doxycycline therapy (British Dental Journal 2003; 194: 491). This had significant ocular effects, and occurred after three weeks' therapy in one reported case. Since writing that abstract, I have seen someone who developed a marked diplopia on the fourth day of a doxycycline course at 100mg per day. This resolved on cessation of the drug.

Tetracyclines have been used for many years in relation to periodontal problems, but with minimal reported adverse effects. It is important that dentists are aware of the occasional severe complications which may occur, and advise patients accordingly of the significance of headaches and ocular symptoms.