Prescribed drugs and neurological complications.
A treatment history is a fundamental part of the healthcare consultation. Current drugs (prescribed, over the counter, herbal remedies, drugs of misuse) and how they are taken (frequency, timing, missed and extra doses), drugs tried previously and reason for discontinuation, treatment response, adverse effects, allergies, and intolerances should be taken into account. Recent immunisations may also be of importance. This article examines the particular relevance of medication in patients presenting with neurological symptoms. Drugs and their interactions may contribute in part or fully to the neurological syndrome, and treatment response may assist diagnostically or in future management plans. Knowledge of medicine taking behaviour may clarify clinical presentations such as analgesic overuse causing chronic daily headache, or severe dyskinesia resulting from obsessive use of dopamine replacement treatment. In most cases, iatrogenic symptoms are best managed by withdrawal of the offending drug. Indirect mechanisms whereby drugs could cause neurological problems are beyond the scope of the current article—for example, drugs which raise blood pressure or which worsen glycaemic control and consequently increase the risk of cerebrovascular disease, or immunosupressants which increase the risk of infection. Different categories of neurological syndromes will be considered.

Prothrombotic drugs are the main consideration, with both arterial and venous effects.

### Stroke

Current users of low oestrogen dose combined oral contraception (COC) have a small increased risk of ischaemic stroke, particularly in women with other risk factors; notably smoking, hypertension, and probably a history of migraine, and a modestly elevated risk of haemorrhagic stroke mainly in women older than 35 years of age. Former users of COC have no increase in risk of ischaemic or haemorrhagic stroke.

Women taking hormone replacement therapy (HRT) have a small increased risk of ischaemic stroke. In the women’s health initiative study 16 608 postmenopausal women on combined HRT (oestrogen plus progesterone) were followed …