This is a randomized, double-blind, placebo-controlled trial to evaluate the safety and efficacy of levosulpiride to improve retinal alterations due to diabetic macular edema and diabetic retinopathy

Diabetic retinopathy (DR) and diabetic macular edema (DME) are the primary cause of irreversible blindness and visual impairment in working-age adults. Nearly 80% of patients with diabetes will experience some degree of DR and DME 15-20 years after diagnosis. Altered blood parameters (glucose, lipids, and pressure) influence disease development and progression; however, the combined values of these parameters account for only 10% of the risk of DR. Laser therapy is effective for preserving sight but is poor for reversing visual loss. Anti-angiogenic therapies are effective and less destructive but require frequent intravitreal delivery, which raises the risk of infection and ocular complications. Therefore, the prevention and treatment of DR and DME should include other modifiable factors. Data from preclinical studies support a protective role for the serum levels of the hormone prolactin. The trial investigates a new specific therapy for DR and DME based on elevating the circulating levels of prolactin with the prokynetic, dopamine D2 receptor blocker, levosulpiride. It is a prospective, randomized clinical study in patients with DR and DME in which ophthalmologic and health parameters evaluated before and after starting the study medication will determine the efficacy and safety of treatment.

Patient registries: Patients are enrolled at the time of a routine health care service. The caregiver and patient together, in a standardized uniform manner for every patient, will collect the data. Data collection procedures are clearly described and include protocols, policies, and the formatted listing of all the data elements, their full definitions and validation rules. All personnel involved in data collection are qualified registry trained. The same physicians, laboratory technicians, and graduate students will evaluate and collect the data from all patients. An individual fully knowledgeable of all protocols, policies, procedures, and definitions in the registry will be designated as Accountable for Data Quality. This individual (coordinator) should ensure that all collected data are complete, accurate, and valid. Data logically inconsistent will be confronted to information in external database. Data collected on formatted paper forms are entered into a computer and electronic registries carefully reviewed by a third party to identify missing data, invalid or erroneous entries, and inconsistent data. Any data review activity and remediation efforts will be documented. Amelioration of data problems may include querying the personnel uploading the data, the coordinator, the interviewer, or the patient. The proposed sample size and study duration are the minimum required and are based on biological models of DR and on clinical experience evaluating primary data associated with the study. These parameters may have to be modified to accommodate the sample size required to obtain clinically important differences and their statistical evaluation, access to eligible patients, lack of adherence to therapy at specific calendar dates (holidays), etc. Statistical methods include those evaluating continuous and categorical variables, incidence and prevalence, the association between a risk factor and outcome, and the relative contribution of confounding factors.

Inclusion Criteria:

• Age equal or greater than 40 years but no older than 69 years
• Male and female subjects with mild and moderate diabetic macular edema (DME), non-proliferative diabetic retinopathy (DR), and with proliferative DR undergoing medically prescribed vitrectomy.
• Signing informed consent
• Without ocular complications: severe myopia (> 6 diopters), ocular media opacity, retinal detachment, etc.
• Without previous ocular treatments: ocular surgeries, retinal laser photocoagulation, intravitreal administration of antiangiogenic agents (delivered < 6 months before enrollment).
• Prolactin serum levels ≤ 20 ng/ml
• With normal or mild loss of kidney function (glomerular filtration rate >60 ml/min) for groups with DME and DR without vitrectomy.
• With mild to severe loss of kidney function (glomerular filtration rate >30 ml/min) for groups with DR undergoing vitrectomy.
• Without contraindications for the use of levosulpiride (Parkinson disease, epilepsy, breast cancer, alcoholism, hypokalemia).
• Without hyperprolactinemia inducing conditions: Pathologies (hypothyrodism, hepatic dysfunction, prolactinomas); Medication (antipsychotics, antidepressants, prokinetics, other)

Exclusion Criteria:

• Not meeting inclusion criteria.
• Adverse and intolerable drug effects.
• Not complying with study medication
• Inability to continue in-hospital appointments.
• Missing outcome data
• Hesitation to continue with study medication
• Relocation to another state or country
• Voluntary withdrawal of consent

It is yet undecided whether case reports will be published in medical journals throughout the course of the study. No identifier linking participants in the study to research records will be made public or reported.

Patients, care providers, and evaluators are blind to treatment allocation. This reduces the risk of bias in the measurement of outcomes, in the decision to modify or discontinue treatment, or to withdraw from trial or from analysis. The monitoring coordinator allocates the treatment.