From the FDA Drug Label
DOSAGE AND ADMINISTRATION ... The usual dosage is 10 to 20 mg Estradiol valerate injection, USP every four weeks The FDA drug label does not answer the question.
From the Research
To convert from estradiol spray 1.53 mg to Delestrogen (estradiol valerate) injections, the equivalent dose would be approximately 5 mg of Delestrogen given every 7 days, considering the latest guidelines and recommendations for injectable estrogen dosing. Since Delestrogen comes as a 20 mg/ml concentration, this would mean injecting 0.25 ml weekly. This conversion accounts for the different pharmacokinetics between the daily topical spray and the longer-acting injectable estradiol valerate, as noted in studies such as 1. The conversion is based on the fact that estradiol valerate is metabolized to estradiol in the body, with estradiol valerate having approximately 76% of the potency of pure estradiol by weight. Additionally, injectable estradiol has higher bioavailability than topical formulations.
When switching between these formulations, it's essential to monitor estradiol blood levels after 4-6 weeks to ensure appropriate dosing, as individual metabolism varies, as suggested by 2. Some patients may experience fluctuations in hormone levels with weekly injections, so symptoms should be monitored and dosing adjusted accordingly. The goal is to achieve therapeutic levels of estradiol while minimizing the risk of supraphysiologic levels, which can be associated with adverse effects.
Key considerations in this conversion include:
- The potency and bioavailability of estradiol valerate compared to estradiol
- The pharmacokinetics of injectable versus topical formulations
- Individual patient factors, such as metabolism and symptom response
- The importance of monitoring and adjusting dosing to achieve optimal therapeutic levels, as emphasized by 1.
By starting with a lower dose, such as 5 mg weekly, and adjusting as needed based on clinical response and estradiol levels, healthcare providers can help ensure safe and effective treatment for patients transitioning from estradiol spray to Delestrogen injections.