There are over 13 million people in the UK who regularly suffer from
leg cramps at night1, preventing them from sleeping.
Some unfortunate people may experience one or two episodes nightly, several times a week. The soreness in the affected muscle may then last well into the next day.
Local massage, heat, or movement of the affected limb may help to both treat and actually temporarily relieve the pain, but Crampex tablets taken before going to bed at night may help to both treat and actually prevent nocturnal cramp.

1 Postgraduate Medicine (February 2002)