Comparison of the effectiveness of enalapril versus amlodipine in controlling blood pressure in the postpartum period: a clinical trial study

Comparison of the Efficacy and Safety of Enalapril versus Amlodipine in Controlling Blood Pressure During the Postpartum Period

A randomized, open-label, parallel-group, controlled Phase III clinical trial will be conducted on 120 patients. Using a block randomization method with block sizes of four, patients will be equally allocated into two groups.

This study will be conducted at Shahid Beheshti University of Medical Sciences-affiliated Mahdieh Hospital in Tehran, as well as hospitals in Qom and Kerman, over a three-month period in 2026–2027.

Age over 18 years and under 40 years Diagnosis of hypertension (systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg) requiring initiation or adjustment of pharmacological treatment

ntervention Group (Enalapril): Patients in this group will receive oral Enalapril at an initial dose of 5 mg once daily. If the target blood pressure (systolic blood pressure <140 mmHg and diastolic blood pressure <90 mmHg) is not achieved after 24 to 48 hours, and the medication is well tolerated, the Enalapril dose will be increased to 10 mg once daily. If necessary, the dose may be adjusted according to the protocol up to a maximum of 20 mg once daily (or 10 mg every 12 hours). Control Group (Amlodipine): Patients in this group will receive oral Amlodipine at an initial dose of 5 mg once daily. If the target blood pressure (systolic blood pressure <140 mmHg and diastolic blood pressure <90 mmHg) is not achieved after 24 to 48 hours, and the medication is well tolerated, the Amlodipine dose will be increased to 10 mg once daily.

Mean reduction in systolic blood pressure Mean reduction in diastolic blood pressure Time to achieve sustained blood pressure control Need for rescue medication with Labetalol Incidence of adverse effects

Randomization Block After screening eligible patients and obtaining written informed consent, participants will be randomly allocated to two groups: the enalapril group and the amlodipine group. Block randomization with blocks of four will be used to generate the random allocation sequence. Each block will contain two allocations to the enalapril group and two allocations to the amlodipine group, with the order of these allocations determined randomly using random number generation software. The resulting allocation sequence will be placed in opaque, sealed, sequentially numbered envelopes. After each eligible patient enters the study, the corresponding envelope will be opened by the person responsible for allocation, and the patient will be assigned to one of the two groups according to the allocation specified in the envelope. Thus, participants will be randomly allocated to the two groups while maintaining a balanced number of participants in each group throughout the allocation process.

Non-personally identifiable data and research-related documentation will be used solely for scientific, educational, and research purposes.

Access period starts 6 months after results are published.

Access to these data will only be possible for researchers, faculty members, graduate students, and other qualified individuals who submit a written request along with a description of the research purpose, data analysis method, and research ethics approval.

The data provided may only be used for scientific analyses consistent with the approved research objectives, including secondary statistical analyses, systematic reviews, meta-analyses, and other relevant research. The data may not be used for any attempt to identify individuals, transfer data to third parties without permission, commercial use, or any use contrary to research ethics.

Applicants seeking data or documentation for this study can first contact Dr. Kimia Motevalian, a physician at Mahdieh Hospital, Tehran, via email or the principal investigator's contact number. If necessary, correspondence can also be conducted through Mahdieh Hospital in Tehran. Requests will be addressed after review and in compliance with the principles of confidentiality, ethical considerations, and data-sharing regulations.

The applicant must submit a formal request to the lead investigator or the relevant committee. The request should include the purpose of the data use, the proposed analysis method, the applicant’s institutional affiliation, and the plan for publishing the results. The requests will be reviewed by the research team or data monitoring committee for compliance with scientific objectives, ethical considerations, and confidentiality requirements. If approved, the anonymized data will be made available to the applicant via a secure method after signing a Data Use Agreement