iFAAM: The Impact of Proton-pump Inhibitors (Antacids) on Threshold Dose Distributions

• detailed case history, blood sampling and prick testing with different foods will performed.
• double blind food provocation with with three meals containing either placebo or walnut in walnut allergic patients will be performed.
• the provocation will be combined with the intake of drug (omeprazole) or placebo (mannitol) blinded in capsules.

Inclusion criteria

• signed informed consent, history of walnut allergy,minimum age 18 years

Exclusion criteria

• • Known hypersensitivity or allergy to Omeprazole, other proton pump inhibitors, mannitol, ingredients of placebo meal

• Drugs not allowed during the study due to proved interaction with Omeprazole: Digoxin, Clopidogrel, Methotrexate, Antiretroviral drugs, Diazepam, Cilostazol, Phenytoin, Warfarin (R-Warfarin) and other Vitamin K antagonists, Phenytoin, Tacrolimus, Clarithromycin, voriconazole, Rifampicin and Hypericum
• Drugs not allowed due to interference with the food challenge (or shortest interval between last treatment and food challenge)
• corticosteroids systemically (2 weeks)
• antihistamines (3 days) except hydroxyzine (10 days)
• ketotifen (2 weeks)
• betablocker (1 day)
• angiotensin converting enzyme (ACE) inhibitors (2 days)
• omalizumab (2 months)

• Women who are pregnant or breast feeding
• Intention to become pregnant during the course of the study
• Lack of safe contraception, defined as: female participants of childbearing potential, not using and not willing to continue using a medically reliable method of contraception for the entire study duration, such as oral, injectable, or implantable contraceptives, or intrauterine contraceptive devices
• Please note that female participants who are surgically sterilised / hysterectomised or post-menopausal for longer than 2 years are not considered as being of child bearing potential.
• Uncontrolled asthma, forced expiratory volume <70% predicted value
• Acute allergic disease
• Chronic urticaria
• Mastocytosis
• Other clinically significant concomitant disease states (major organic or infectious diseases, e.g., renal failure, hepatic dysfunction, cardiovascular disease, acute febrile infection),
• Known or suspected non-compliance, drug or alcohol abuse,
• Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. of the participant,
• Participation in another study with investigational drug within the 30 days preceding and during the present study