Istamet is a combination of Two drugs, Sitagliptin and Metformin. Metformin may cause Diarrhoea. But no research has stated constipation as a side-effect. But there may be some chance that Zivast can induce constipation in some cases.

There are a variety of medications available for constipation. Medications are available in powdered, tablet, and syrup form, and should be taken before sleeping.

Each medicine acts by its mechanism. For example, some may work by pushing water into your stools and making them soft, bulky and easy to pass. At the same time, others may increase the pushing power of your intestine. Consult a doctor for a medicine that suits your body.

Generally, these medications do not have a good taste. Hence, many do not continue them for an extended period. 

So before you start these medications, try some lifestyle changes.

• Try drinking water a litre more than you usually drink. 
• Include fruits (in control as it contains fructose) and green leafy vegetable fibres in your diet.
• Exercise regularly. 

Read more about glycemic index.