Definition
A dose is usually the amount of an active pharmaceutical ingredient or drug intended for administration. It is often expressed in milligrams (mg). However, indications such as micrograms (µg), grams (g), or millimoles (mmol) are also commonly used.
Examples and terms
The aromatase inhibitor letrozole is commercially available in the form of film-coated tablets containing 2.5 mg of active ingredient. The dose for treating a breast cancer is 2.5 mg per 24 hours. Other medications, such as the pain reliever ibuprofen, are taken several times a day, for example, 1 tablet of 400 mg three times a day. For this example, the (ED) is 400 mg and the (TD) is 1200 mg. The (MTD) is 2400 mg for adults depending on the indication. Also defined is the (MED), which is 800 mg for ibuprofen according to the SmPC. The interval between individual doses is called the dosing interval. For some drugs, for example, antiepileptics or antidepressants, a lower so-called is given at the beginning of treatment, which is slowly increased until the increased, which is subsequently taken regularly.
The dose makes the poison (dose-response relationship).
In a discussion of the dose, Paracelsus must not be omitted. The effect of a drug is dose-dependent. If the dose is too low, no effect is to be expected – if, on the other hand, it is too high, side effects, poisoning and death can occur. The dose is the amount that leads to exitus. Only at one does the drug begin to have an effect. This varies between individuals. If a higher dose is given, within the tolerable maximum doses, a stronger effect can usually be expected at first, until the maximum effect is reached. After a certain dose, no further increase is then possible. An increased dose does not necessarily lead to a stronger effect. This has been shown, for example, for latanoprost eye drops. Here, an increase in dose leads to a weakening of the effect.
