Is it ever necessary to increase dDAVP doses?
The dose of dDAVP required to control CDI should not change over time, unless the patient is a growing child, in which case it may increase gradually in proportion to size. If the dose of dDAVP required to control CDI does increase significantly, it is usually because the efficiency of absorption has decreased (for example, when a patient using the nasal spray develops hay fever or a cold). Occasionally, the dose requirements increase because the patient develops antibodies to dDAVP, but this is very rare. Incidentally, the dose of dDAVP should be determined by its effects on urine output, NOT by its effect on plasma sodium. The latter is determined primarily by the rate of fluid intake, which can and should be regulated separately. In most cases, the thirst mechanism will adequately regulate fluid intake without any interference from care givers. Occasionally, however, in patients who are very young, unconscious, or lack a normal thirst mechanism, it is necessary to regulate fluid int
