Voltarol Emulgel P is a diclofenac diethylammonium gel that can "relieve pain and inflammation in osteoarthritis of the joints", the manufacturer said.
The new pack size – launched at the beginning of March – will supply a patient with enough gel "for a two-week flare-up", GSK added.
The gel is already available in 30g, 50g and 100g tubes.
Alongside the product launch, Voltarol is working with charity Arthritis Research UK to share a programme of exercises to "help people manage their mild osteoarthritis and keep moving", GSK said.
One 180g pack of Voltarol Emulgel P retails at £19.99.
To order Voltarol Emulgel P, call 0800 783 8881.