Should CDI patients wait for symptoms to appear before taking dDAVP?
In the usual patient with uncomplicated CDI, there is no need or benefit to waiting for symptoms to appear before taking the next dose of dDAVP. It is preferable to take the drug in doses or with a frequency that prevents breakthrough because this regimen is not only more convenient, it minimizes fluctuations in hydration, which, in the long run, may have deleterious effects. If taking dDAVP this way results in water intoxication (typified by symptoms of headache, nausea, and dizziness and a fall in blood sodium to abnormally low levels), it is usually because the patients thirst mechanism is abnormal. This abnormality can occur in association with CDI or as an isolated defect that causes symptoms and signs closely resembling the other forms of DI. If water intoxication does develop with dDAVP, special methods of diagnosis and treatment can be used to resolve the situation.
