Dosage Optimization for Letrozole Treatment
Condition: Infertility
MeSH terms: Infertility
Study type: Interventional
Phase: Phase 4

Summary: 
      In a prospective interventional study, 44 Clomiphene resistant infertile patients were
      selected from Abolfazl Infertility Clinic of Bushehr University of Medical Sciences.
      Letrozole was given orally in a dose of 2.5mg, 5mg and 7.5mg, respectively. If the patient
      displayed no response, the dosage was increased. The size of follicle, endometrial thickness,
      estradiol, complications and clinical pregnancy rate were evaluated as the final outcome.
    

Detailed description: 
      In this prospective intervention, the investigators studied Abolfazle outpatients who were
      referred to us by Bushehr University of Medical Sciences in Iran between January 1, 2008 and
      December 30, 2010. The study was approved by the institutional Ethics Committee of Bushehr
      University of Medical Sciences and all patients were required to provide written informed
      consent before the study commenced.There were 3 steps in which the investigators prescribed
      letrozole (Femara,Novartis,Quebec,Canada). In all cases, daily administration began on the
      3rd day of the menstrual cycle through to the 7th day (totaling 5 days). In the first step
      the investigators prescribed letrozole at a dose of 2.5 mg (one tablet) for one or two cycles
      according to the patient's response. Normal follicular size and endometrial thickness were
      considered 18-24 mm and 6 mm or more respectively.1 If the follicle was deemed not
      acceptable, the dose of letrozole was increased at the next cycle.

      At the second and third steps the investigators prescribed letrozole at a dose of 5 mg daily
      and 7.5 mg/day,respectively and according to patient's response, repeat the same dose.

      In the current study the investigators tested the hypothesis that prescribing letrozole as an
      ovulation induction agent in infertile women would increase pregnancy rate, ovulation and
      follicle number (at the normal size range of 18-24 mm), endometrial thickness (to normal
      thickness of 6 mm) and not have considerable side effects in the patients. The primary
      outcome measure was normal follicular size and the secondary outcome measure were the
      clinical and current pregnancy rates. Clinical pregnancy was considered as the presence of a
      gestational sac with fetal heart activity. Letrozole tablets were prescribed by an
      experienced nurse who throughly explained the method of use to the patients. Sonography was
      done by an experienced radiologist.

      The nurse prescribed letrozole to the patients and the university hospital laboratory's
      technician did not know past medical history of clomiphene resistance of the patients. The
      radiologist did not have any knowledge about the drugs prescribed to the patients. Side
      effects and complications of Letrozole were detailed to all patients by an obstetrician.
      Statistical analysis was performed by the Statistical Package for Social Science version 11.5
      for windows (SPSS Inc., Chicago. IL). The data was analyzed by student's t-test and
      chi-squared test for linear trend and comparing proportions. A P-value of <0.05 was
      considered to be statistically significant.
    

Intervention name(s): Letrozole
Intervention type(s): Drug
Intervention description(s): 2.5 mg /day for 5 days
Other intervention name(s): Femara
Intervention MeSH terms: Letrozole
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: clomiphene citrate; infertility; letrozole