Definition
Instructions to take a drug fasting usually mean to administer it at least one-half to one (or even two) hours before or no earlier than two hours after eating. The full details can be found in the patient information leaflet and in the specialist information leaflet. This is why it is also referred to as taking it “between meals”. With such agents, it is generally recommended that other medications or dietary supplements also be taken at an appropriate interval, as these can also interfere. Sober does not refer to abstaining from alcohol. Whether this is also indicated must be assessed on an individual basis.
Reasons for taking sober
Why must medications be taken sober – that is, not with food? Most often, the reason is to affect intestinal absorption. Food components or the altered environment may inhibit absorption of the active ingredients into the bloodstream, reducing bioavailability.
Intake Errors
If a drug that should be administered fasting is taken with a meal, this may result in a weaker effect or loss of effect because the active ingredients are not adequately absorbed into the body and do not reach the site of action. The effect on bioavailability can be quite relevant (e.g. 30% or 50%). To prevent errors, healthcare professionals should draw the patients’ attention to the correct intake. The correct choice of words is important. “Before eating” is not sufficiently precise – it could also mean immediately before eating. The statement must be supplemented with the correct time interval.
Examples (selection)
- Tetracycline
- Bisphosphonates
- Bilastin
- Thyroid hormones: levothyroxine (an example of taking 30 min before breakfast).
- Proton pump inhibitors, e.g. lansoprazole.
- Trametinib
