Evaluation of the Efficacy of Oral Theophylline on Clinical Symptoms of Cardiac Syndrome X at Shahid Rajaei Hospital, Karaj

To evaluate the efficacy of oral theophylline on improving clinical symptoms, reducing the frequency and severity of anginal pain, enhancing physical capacity, and improving the quality of life in patients with cardiac syndrome X at Shahid Rajaei Hospital, Karaj

A randomized, placebo-controlled, double-blind, parallel-group, phase 3, single-center clinical trial on 46 patients; Block randomization with variable block sizes of 4 and 6; Allocation concealment using sequentially numbered, opaque, sealed envelopes; Blinding includes patients, data collector/investigator, and statistical analyzer

The study will be conducted at the angiography unit and specialized cardiology clinics of Shahid Rajaei Hospital, Karaj; Eligible patients will be screened and enrolled after signing an informed written consent; The standard Seattle Angina Questionnaire (SAQ) will be completed at baseline; Patients will then be randomly allocated to either group, and after 4 weeks of intervention, the SAQ will be completed again to evaluate changes in clinical symptoms

Inclusion: Definite CSX with angina, positive MPI and normal/mild CAD (<50%); Normal EF and no major valvular disease; Exclusion: CAD >50%; Pregnancy; History of seizures or severe ventricular arrhythmias; Severe asthma or COPD; Concurrent use of beta-blockers, CCB, or ranolazine

Intervention group: Patients receive oral theophylline tablets 100 mg daily for 4 weeks; Control group: Patients receive placebo tablets, completely identical in appearance, color, taste, and packaging to the active drug, for 4 weeks

Changes in the scores of the 5 dimensions of the Seattle Angina Questionnaire (SAQ) including: physical limitation; angina stability; angina frequency; treatment satisfaction; quality of life; before and after 4 weeks of intervention

Participants will be randomized in a 1 to 1 ratio into the intervention or control groups using block randomization with variable block sizes of 4 and 6 The allocation sequence will be generated by an independent epidemiologist using Stata software To ensure allocation concealment the assignments will be placed in sequential numbered opaque and sealed envelopes Upon enrollment of each participant the corresponding envelope will be opened to determine the treatment assignment

The study is designed as a double blind clinical trial Theophylline 100mg tablets and placebos will be manufactured to be completely identical in appearance color packaging and taste Patients the investigator who collects data and the statistician who analyzes data will remain fully blinded to the group allocations until the statistical analysis is completed

To protect patient confidentiality and privacy and in accordance with the ethical and legal regulations of Alborz University of Medical Sciences individual participant data will not be publicly shared and study findings will only be published as aggregate data in scientific journals