Medications for diarrhoea work by lining the gut to protect it whilst it heals, other medications work by reducing intestinal movement. If your pet is suffering with diarrhoea it would not be uncommon for your vet to prescribe more than one medication and/or a change of diet.
I have heard that this drug can have side effects, how will this affect my pet?
All medicines have potential side effects but this does not mean your pet has a high risk of experiencing them, the side effect most commonly associated with diarrhoea treatment is constipation. If you notice anything unusual or your pet develops a high fever, contact your vet as a matter of urgency.
Possible drug interactions
Ensure your vet is aware of any other medication you are giving your pet. Drug interaction is not uncommon when two differing medications are prescribed and is highly likely when treating diarrhoea symptoms.