'proconvulsant' originates from Modern English, formed by prefix 'pro-' (from Latin 'pro', meaning 'for' or 'in favor of') + 'convulsant' (from 'convulse' + '-ant').

'convulse' changed from Latin 'convulsus' (the past participle of 'convellere' / 'convellere', where 'con-' meant 'together' and 'vellere' meant 'to pull') and entered English via Medieval/Late Latin and Old French forms (e.g. 'convulsio' / 'convulser') into Middle English as 'convulse'; from this root came 'convulsant' and later the compound 'proconvulsant' in medical usage.

Initially, the Latin root referred to a violent pulling or wrenching ('to pull together violently'), but over time the sense shifted to describe violent involuntary muscular contractions; the modern meaning is 'causing convulsions'.