Observational Study of the Local Tolerability of Injectable Progesterone Microspheres

Background: As intramuscular progesterone administration is associated with local intolerance, the purpose of this work was to determine the local tolerability of a new progesterone microsphere suspension, administered by intramuscular injection. Methods: An observational, longitudinal, prospective, analytical, multicenter, active pharmacovigilance study was conducted. Two hundred and seven progesterone microsphere administrations were evaluated. Patients evaluated pain, burning sensation, pruritus and dysesthesia. Physicians evaluated erythema, pallor, petechia, ecchymosis, bleeding, edema, induration, abscess, macule, papule, vesicle and pustule. Local tolerability was evaluated using a visual analog scale (100-mm line) on the day of administration, and subsequently on days 3 and 7. Local symptoms were evaluated by patients and local signs by the attending physicians. Results: On the day of application, 68.4% of the administered doses were associated with ‘absent’ or ‘mild’ pain, rising to 91.2% on the 7th day; 83.0% of doses were associated with ‘absence’ of or a ‘mild’ burning sensation on the day of administration, rising to 99.5% on day 7. On administration day, 13.2% reported ‘mild’ erythema and 1.0% ‘moderate’ erythema, and 3.9% of doses had ‘mild’ induration and 0.5% ‘moderate’ induration, which increased to 16.6 and 2.9% on day 3, respectively. The values for pallor, ecchymosis, bleeding, edema and pustule were lower than 10 mm (of 100 mm) on the application day and behaved similarly in subsequent days. There were no reports of petechia, abscess, macule, papule or vesicle with the dose application. Conclusions: Progesterone microspheres were well tolerated without serious or unexpected adverse effects.