Movicol takes around 8-12 hours to work and relieve constipation.
Please feel free for your follow up questions.
Two sachets are good enough for today. Drinking more water and fluids than normal (around a liter in next 12 hours and 2.5 in next 25 hours in total) would be helpful further for the Movicol action, as it is an osmotic laxative and absorbs water to make the bulk of stool, which relieves the constipation.
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