The present study investigates the involvement of the gut hormone glucose-dependent insulinotropic polypeptide (GIP) in the pathophysiology of postprandial hypotension (PPH)

The study is an exploratory, randomised, placebo-controlled, double-blind crossover study comprising two experimental days with an infusion of the GIP receptor antagonist, GIP(3-30)NH2 (NH2 is the aminogroup), and placebo (saline) during a 180-minute mixed meal test (MMT). Eighteen participants, men and women, with MMT confirmed PPH will be included in the study.

Inclusion Criteria:

1. Age 18-85 years
2. History of PPH-related symptoms like dizziness, lightheadedness, palpitations, or fainting after meal ingestion
3. Informed consent

Exclusion Criteria:

1. Not fulfilling the PPH diagnosis during the mixed meal test or during the test meal with increased (+25%) number of calories
2. Treatment with antihypertensives
3. Treatment with SNRI (Serotonin and Noradrenalin Reuptake Inhibitor) or treatment within three months before screening visit
4. Allergy or intolerance to ingredients included in the mixed meal
5. Any ongoing medication that the investigator evaluates would interfere with trial participation
6. Any physical or psychological condition that the investigator evaluates would interfere with trial participation, including any acute or chronic illnesses
7. Anaemia (haemoglobin below normal range <7.3 mmol/L for women and <8.3 mmol/L for men)
8. Moderate to severe loss of kidney function (estimated glomerular filtration rate (eGFR) <45 ml/min/1.73 m2) at screening
9. Known liver disease (except for simple steatosis) and/or elevated plasma alanine aminotransferase (ALT) > three times the upper limit of normal at screening
10. Any concomitant disease or treatment that, at the discretion of the investigators, might jeopardize the participant's safety during the trial
11. Alcohol/drug abuse as per discretion of the investigators
12. Pregnancy or breastfeeding
13. Participation in any other clinical trial during study period
14. Mental incapacity or language barriers that preclude adequate understanding or cooperation or unwillingness to comply with trial requirements or pr discretion of the investigator