Examining the Influence of the Route of Administration and Dose of Estradiol on Serum Estradiol and Testosterone Levels in Feminizing Gender-Affirming Hormone Therapy.

INTRODUCTION: Individuals may seek gender-affirming hormone therapy (GAHT) to align their physical appearance with their gender identity. Feminizing GAHT typically involves the use of estrogen. This study investigates the effect of route of administration (ROA) and dose of estradiol on estradiol (E2) and testosterone (T) levels in transfeminine individuals. METHODS: We conducted a chart review of 573 patients with an active prescription for estradiol for feminizing GAHT and serum hormone levels available. Multiple linear regression and analysis of variance were used to analyze the effect of dose and ROA of estradiol on serum E2 and T. RESULTS: Oral estradiol was the only ROA demonstrating a linear dose-response, with each 1 mg/d increase associated with a reduction in T of 19.03 ng/dL (P = .005). Lower T levels were seen with higher doses of transdermal estradiol but a significant dose-response was not demonstrated. Intramuscular estradiol was associated with lower T and higher E2 compared to oral and transdermal ROAs (P < .001), with many achieving target hormone levels even at low doses. Higher doses of oral estradiol were associated with lower mean serum leutenizing hormone and follicle stimulating hormone levels (P < .05). CONCLUSION: Oral estradiol can be titrated to achieve a stepwise decrease in serum T. The intramuscular ROA appears to be the most potent delivery of estradiol with impact on serum hormone levels with doses on the low end of guideline-suggested ranges. Serum leutenizing hormone and follicle stimulating hormone may also help with the management of feminizing GAHT.

ALSUntangled #66: antimycobacterial antibiotics.

Several infections have been associated with motor neuron diseases resembling ALS, including species of viruses, bacteria, and parasites. Mycobacterium avium subspecies paratuberculosis (MAP), most known for its probable etiologic association with Crohn's disease, has been suggested as another possible infectious cause of motor neuron disease. Two published case reports describe the successful treatment of ALS-like symptoms with antimycobacterial antibiotics. Both cases had atypical features. Based on these, we believe it would be reasonable to begin performing chest imaging in PALS who have features of their history or exam that are atypical for ALS such as pain, fevers, or eye movement abnormalities. If the chest imaging is abnormal, more specific testing for mycobacteria may be indicated. Until there is more clear evidence of an association between mycobacteria and ALS, we cannot endorse the widespread use of potentially toxic antimycobacterial antibiotics for PALS.

ALSUntangled #60: light therapy.

ALSUntangled reviews alternative and off-label treatments for people with ALS. Here we review light therapy. We show that it has theoretically plausible mechanisms, three flawed pre-clinical data, studies, and one incompletely documented case report supporting its use. We explain why further studies are needed to determine whether any specific light therapy protocol can help people with ALS.

ALSUntangled 59: Tamoxifen.

Here we use the ALSUntangled methodology to review Tamoxifen as an ALS treatment. We show that it has plausible mechanisms, a positive preclinical study, a case report and 2 small trials suggesting benefits. We show that it appears reasonably safe, though there is a small risk of developing cancer with long term use. While we cannot yet endorse this as an ALS treatment, there is enough evidence to warrant another larger ALS trial.