From the Guidelines
To convert DDAVP (desmopressin) from subcutaneous (SC) to oral (PO) administration, a conversion ratio is not explicitly provided in the given evidence, however, based on the information available, oral desmopressin is administered in doses of 0.2 to 0.6 mg nightly 1. Given the lack of direct conversion information, we must consider the oral dosing guidelines provided. The oral form of DDAVP is available as a 0.2-mg tablet, and children with enuresis are started on one tablet before bedtime, with the dose incrementally increased to two or three tablets at bedtime if the lower dose proves ineffective 1. When switching from subcutaneous to oral administration, it's crucial to monitor the patient closely for efficacy and adjust the dose as needed, considering the potential for different absorption rates and first-pass metabolism effects. Patients should also be advised about fluid restriction in the evening to prevent hyponatremia, a potential side effect 1. Key points to consider in the conversion and administration of DDAVP include:
- Oral desmopressin doses range from 0.2 to 0.6 mg nightly 1.
- Starting dose is typically one 0.2-mg tablet at bedtime, adjustable based on response 1.
- Monitoring for efficacy and side effects, such as hyponatremia, is essential 1.
- Fluid restriction in the evening is recommended to minimize the risk of hyponatremia 1.
From the Research
Conversion of Desmopressin (DDAVP) from Subcutaneous (SC) to Oral (PO) Administration
- The conversion of Desmopressin (DDAVP) from subcutaneous (SC) to oral (PO) administration can be determined by considering the bioavailability of the drug via different routes of administration 2.
- A study found that the bioavailability of DDAVP after oral administration was 0.1% compared to subcutaneous administration 2.
- Another study reported that the average oral DDAVP dose required to control diuresis was 19 +/- 2 times more than the prior intranasal treatment, which can be used as a reference for conversion 3.
- A retrospective analysis of 56 patients found that the mean oral dosage of DDAVP was 417 micrograms, compared to a mean nasal dosage of 20.4 micrograms, resulting in a dosage ratio of about 20 4.
- This dosage ratio is consistent with the bioavailability of the drug, suggesting that the oral dose of DDAVP may need to be significantly higher than the subcutaneous dose to achieve the same therapeutic effect 2, 4.
- For example, if a patient is receiving 2 micrograms of DDAVP subcutaneously, the equivalent oral dose may be around 200-400 micrograms, depending on the individual patient's response and the specific formulation of the oral tablet 2, 3, 4.