Nimodipine to Prevent LH Surge During Ovulation Induction: Blinded Placebo-controlled RCT
Using Nimodipine, a Calcium Channel Blocker, to Prevent LH Surge in Women Undergoing Controlled Ovarian Stimulation and Intrauterine Insemination: a Double-blinded, Randomized Controlled Study
  • Phase

  • Study Type

  • Intervention/Treatment

    nimodipine ...
  • Study Participants

The main purpose of this study is to test the effectiveness of nimodipine in preventing a luteinizing hormone (LH) surge in women undergoing ovulation induction with clomiphene citrate. It is important to prevent the premature LH surge in controlled ovarian stimulation to allow adequate recruitment of follicles, proper maturation of a dominant follicle before ovulation, and effectively time insemination with semen to allow fertilization of a mature egg to occur.

The investigators are also conducting this study to determine medication side effect profile (including lightheadedness or dizziness from low blood pressure or rapid heart rate, headache, and nausea), patient treatment compliance, and clinical pregnancy (positive pregnancy test and ultrasound evidence of fetal heart rate). Finally, LH and follicle stimulating hormone (FSH) serum levels will be measured to determine effect of nimodipine on these hormones.

As a calcium channel blocker, nimodipine has been shown to block calcium mediated release of gonadotropin releasing hormone in animal and preliminary human studies. The investigators hypothesize that nimodipine, a calcium channel blocker, will prevent or delay the LH surge during controlled ovarian stimulation cycles using clomiphene citrate in subfertile patients undergoing assisted reproduction with intrauterine insemination (IUI).
After enrollment, subjects will be randomized to Placebo Comparator or Active Comparator. All subjects will receive Clomid 100 mg for 5 days for the purpose of ovarian follicle recruitment. Intervention will be initiated once ovarian follicle maturation has been documented (≥1 ovarian follicle size of ≥ 17mm) and the absence of a premature LH surge has been confirmed - this will be classified as intervention day 0. Subjects will receive their assigned comparator (Placebo or Active) according the schedule below:

Intervention Day 0 - noon / afternoon / bedtime (3 doses)
Intervention Day 1 - morning / noon / afternoon / bedtime (4 doses)
Intervention Day 2 - morning (1 dose) Serum hormone levels and ultrasound examination will occur on days 0,1 and 2 for all subjects.
Study Started
Sep 30
Primary Completion
Apr 30
Study Completion
Apr 30
Results Posted
Aug 11
Last Update
Aug 11

Drug Placebo

oral administration

Drug Nimodipine

oral administration

  • Other names: Nimotop

Placebo Placebo Comparator

All subjects in both arms will receive Clomid 100 mg tablets by mouth for 5 days prior to receiving either placebo comparator or active comparator. Placebo comparator subjects will receive 8 total doses of liquid placebo orally 4 times a day for 8 total doses in pre-filled liquid placebo containing syringes

Nimodipine Active Comparator

All subjects in both arms will receive Clomid 100 mg tablets by mouth for 5 days prior to receiving either placebo comparator or active comparator. Active comparator subjects will receive Nimodipine 30mg liquid orally 4 times a day for 8 total doses in pre-filled syringes


Inclusion Criteria:

Age 25-40 years at the time of enrollment
Both ovaries intact by history and ultrasound assessment
Early follicular phase (day 2-4) serum FSH level <20 mIU/mL
Diagnosis of subfertility with a recommended treatment of COH and IUI
Providing written informed consent in English

Exclusion Criteria:

Body mass index (BMI) >38 kg/m2
Early follicular phase (day 2-4) serum FSH level ≥20 mIU/mL
History of overstimulated cycle defined as >3 mature follicles of ≥17 mm
Abnormal uterine cavity and/or tubal disease (as evidenced by sonohysterogram or hysterosalpingogram)
Diagnosis of infertility with a clear indication for in-vitro fertilization, such as bilateral tubal occlusion
Severe male factor infertility: Total Motile Sperm Count < 2x106 post washing (sperm deemed inadequate for IUI preparation)
Any ovarian or abdominal abnormality that may interfere with adequate TV ultrasound evaluation
Absence of one or both ovaries
Any contraindication to being pregnant or carrying a pregnancy to term
Unexplained gynecological bleeding
Any medical condition that would jeopardize the patient or the integrity of the data obtained including:
Prior reaction or side effects from previous calcium channel blocker use
Any medical condition that may interfere with the absorption, distribution, metabolism or excretion of nimodipine such as hepatic disease, hypertension, seizure, concurrent infection, depression, reflux (see #12 below).
Mental health status resulting in cognitive or emotional impairment that would preclude study participation
The concurrent use of any of the following drugs: [These medications have been shown to effect the availability of the medication or worsen hypotension symptoms]
Antihypertensives (eg. ACE inhibitors, alpha-adrenergic blocking agents,methyldopa, beta-blockers, diuretics, PDE5 inhibitors, and other calcium antagonists)
Antiepileptics (eg. phenobarbital, phenytoin, carbamazepine or valproic acid)
Macrolide antibiotics (eg, erythromycin)
Azole antimycotics (eg, ketoconazole)
HIV protease inhibitors (eg, ritonavir)
Antidepressants (eg, nefazodone and fluoxetine)
Patient unable to communicate adequately with the investigators and to comply with the requirements of the study
Unwillingness to give written informed consent




All Events

Event Type Organ System Event Term Placebo Nimodipine

LH Surge

Compare the change between placebo treated and nimodipine treated patients by the presence or absence of an LH surge on intervention Day 1 and Day 2. LH surge will be determined by serum LH levels at least two times the baseline serum LH (baseline serum LH = (cycle day 3 serum [LH] + cycle day 7 serum [LH])/2).



Number of Participants Experiencing Side Effects

Medication side effect profile including: symptomatic hypotension (Note: vital signs will be recorded), symptomatic tachycardia (Note: vital signs will be recorded), headache, nausea. These will be self-reported with constructed questionnaire.



Gonadotropin Levels

Calculated changes in serum LH, FSH, and estradiol levels between patients in nimodipine and placebo arms

Outcome Measure Data Not Reported



Age, Continuous

years (Mean)
Full Range: 31.0 to 42.0

Race (NIH/OMB)

Sex: Female, Male

Overall Study



Drop/Withdrawal Reasons