MP76-05 TWICE PER WEEK DOSING OF INTRAMUSCULAR TESTOSTERONE (T) IS ASSOCIATED WITH GREATER RISK OF ERYTHROCYTOSIS
I wish they had tried 50 mg twice per week instead of 80-150 mg twice per week.
INTRODUCTION AND OBJECTIVES
With an increasing awareness for mens health, marketing for pharmaceutical sales of testosterone products has increased over 170% over the last 5 years as reported by Layton et. al with a 100-fold increase in the market over the last 3 decades. The most common dose-limiting adverse effect of testosterone therapy (TTh) is erythrocytosis, which may exacerbate pre-existing vascular disease and increase the risk for thromboembolic complications. The increased risk of erythrocytosis with injectable testosterone over that of topical applications has been established. We sought to determine if the incidence of erythrocytosis, as defined by a hematocrit (Hct) > 52%, in patients on injectable TTh was significantly changed by more frequent, lower dose T injections.
METHODS
A sample of 55 men using injectable T (cypionate or enanthate) for symptomatic hypogonadism at a single dose and frequency was selected for analysis from a single center mens health database. Age, T dosage, frequency of administration, duration of T therapy, and Hct were extracted through retrospective chart review. The cohorts were separated into 27 men on 200mg of T once weekly (QW) and 28 men on
80-160mg of T twice weekly (BIW). Indication for BIW dosing was a return of hypogonadal symptoms prior to the administration of the next dose. The maximum Hct was identified for each individual and the cohort mean of the maxima was calculated. The difference in numerical variables was assessed via Mann-Whitney U analysis.
RESULTS
No significant difference was identified between the mean (range) age of the QW and BIW cohorts (43.2 (27-63) years vs. 40.6 (27-62) years), respectively (p=0.36). Erythrocytosis occurred in 11% of the QW cohort with a maximum Hct (Interquartile Range) of 49.2 % (43.4, 54.6). In contrast, a maximum Hct of 51.4 % (45.7, 56.9) was observed in the BIW cohort, with 29% of men developing erythrocytosis. Statistical significance was identified in comparing the percent erythrocytosis of the two cohorts (p=0.007). The rate of erythrocytosis, defined as the number of days until maximum Hct while on testosterone, was comparable in both groups (p=0.18).
CONCLUSIONS
Although the rate of erythrocytosis is comparable among BIW and QW dosing, more frequent dosing of injectable T is associated with a higher maximum Hct and a higher incidence of erythrocytosis. These data suggest that dosing frequency, rather than total T dose, is an important factor in development of erythrocytosis in men on injectable TTh.
American Urological Association
According to this study someone on another forum posted, twice per week injections was associated with higher hematocrit than once per week injections. Anyone have any thoughts?
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pubmed.ncbi.nlm.nih.gov
