From £3.52 per pack.
Source: NHS Drug Tariff (what the NHS pays per pack), 7 Nov 2026. What you pay at the counter can be higher (pharmacy fees, insurance).
In United Kingdom, Lactulose costs from £3.52 per pack (NHS Drug Tariff (what the NHS pays per pack)).
Ask the pharmacist for a generic version with the same active ingredient and strength: it works the same and usually costs much less. Compare a few licensed pharmacies, and never buy medicine from unlicensed sellers to save money.
Check the registration number on the pack with PillVera, look at the expiry date, and buy from a licensed or verified pharmacy. A price far below everyone else's is a warning sign.