Clinical Evaluation of Montelukast in Veterans With Gulf War Illness

Eligibility Criteria

• * Gulf War Veterans of the U.S. military deployed on military orders to the Persian Gulf Region between August 2, 1990, and December 31, 1991
• * Diagnosed with GWI according to the CDC and modified Kansas criteria as recommended by the Institute of Medicine (IOM), that is, endorse multiple or moderate-to-severe symptoms, with symptom onset during or after deployment to the Persian Gulf region in 1990-1991, persisting for six months or longer, in at least 3 of 6 domains:
• 1. fatigue/sleep disturbances
• 2. neurological/cognitive/mood symptoms
• 3. somatic pain
• 4. gastrointestinal problems
• 5. respiratory symptoms
• 6. skin symptoms
• * Self-reported cognitive dysfunction based on a T-score of 40 or less on the PROMIS v2.0 Cognitive Function 8a short form
• * Be able to:
• * provide written consent and be able to communicate with the research team in verbal and written English
• * attend the two in-person study encounters
• * have reliable telephone service for the eight weekly telephone encounters
• * Diagnosed by a physician with any chronic condition that may explain their profile of symptoms or prevent their ability to accurately report them including:
• * chronic autoimmune conditions
• * systemic inflammatory conditions
• * cancer not in remission at least 5 years
• * congestive heart failure
• * anemia
• * multiple sclerosis
• * amyotrophic lateral sclerosis (ALS)
• * poorly controlled diabetes
• * post-chemo or radiation syndromes
• * sickle cell anemia
• * symptomatic Coronary Artery Disease (CAD)
• * chronic liver disease
• * chemical insufficiency
• * morbid obesity (body mass index (BMI) \>= 40)
• * human immunodeficiency virus (HIV)
• * alcohol/substance use disorder/stimulant/opioid/other depressant misuse in the past year
• * major mental health condition (e.g., psychosis, suicidal ideations, major depressive disorder) that interferes with their ability to accurately report symptoms
• * hospitalized or undergoing invasive procedures in the past 12 months due to exacerbations of any chronic conditions (such as diabetes, coronary artery disease, hypertension, or emphysema)
• * elevated liver enzymes (2.5 times upper limit of normal) at baseline visit
• * estimated glomerular filtration rate less than 60 ml/min/1.73 sqm at baseline visit
• * hemoglobin less than 10 g/L at baseline visit
• * evidence of poorly controlled chronic conditions listed above, or others that may mimic GWI as per the PI, either by self-report, Veterans Health Administration (VHA) electronic health record information review, laboratory testing or physical examination
• * Changes in medications for chronic conditions in the 3 months preceding enrollment (based on self-report)
• * Suicidal ideation based on their responses on the Columbia Suicide Risk Inventory
• * Prescribed or taking Montelukast in the past 6 months for any reason
• * Taking 2 or more medications with moderate interactions with Montelukast
• * Pregnancy or intention to become pregnant
• * Active homicidal ideation
• * COVID-19 illness (confirmed or suspected) without recovery to pre-COVID health status