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

Study Overview
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Brief Summary
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In patients with a walnut allergy double blind placebo controlled food challenge with walnut will be combined with the intake of proton pump inhibitor (PPI) or with placebo to assess the impact of PPI on threshold level and on clinical manifestation.

Detailed Description
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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.

Official Title
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Integrated Approaches to Food Allergen and Allergy Risk Management: iFAAM: The Impact of Proton-pump Inhibitors (Antacids) on Threshold Dose Distributions

Conditions
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Food Allergy

Intervention / Treatment
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* Drug: Omeprazole
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Omeprazole<br>patients will take Omeprazole 40mg, in capsules, once a day, during five days before walnut challenge | Drug: Omeprazole<br>* patients with walnut allergy will be exposed during 5 days before food challenge with Omeprazole<br>* Other names: Omeprazol Sandoz eco Kps 40;|
| Sham Comparator: Placebo<br>patients will take Mannitol, in capsules, once a day, during five days before walnut challenge | Drug: Placebo<br>* patients with walnut allergy will be exposed during 5 days before food challenge with Placebo<br>* Other names: Mannitol;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| amount of walnuts that induces an allergic reaction assessed in milligram | The amount of walnut which induces an allergic reaction in walnut allergic patients will be assessed in milligram by titrated challenges under concommitant intake of therapeutic doses of omeprazole versus placebo | up to 18 months |