How do medicines have an effect?
Each medicine has its own mode of action. Medicinal substances are generally used to either strengthen or prevent the body's own physiological processes.
Medicines have different effects on different people
The same medicines do not work on everyone. Even the same illness can be treated in different people individually with different medicines, and even the same medicine may be needed with different doses of the active ingredient in different people. The dose is affected by the pharmaceutical form and route of administration used. In the beginning of medicinal treatment, it may be necessary to test several different medicines before the suitable medicine and dose are found.
Many medicines can be used for different purposes for different people. Antidepressants, for example, can be used as sedatives or painkillers in low doses.
The patient's age affects the effectiveness of a medicine. The strength of the medicine's effect in children, adults, and the elderly may be different. The effects of medicines can be affected by physiological factors, illnesses, and other medicines.
Particularly when the functioning of the kidneys or the liver deteriorates, the excretion of many medicinal substances slows down.
The safety and efficacy of many medicinal substances is based on the patient’s individual genome. Various kinds of gene tests can be used for determining the suitability of medicines for an individual patient and for defining suitable dosing individually. This is referred to as personalised medicine.
The effect can be immediate or delayed
The effect of a quick-relief asthma medicine can be noticed immediately as easier breathing, but the effect of asthma control medication becomes apparent only after weeks of regular use as fewer asthma attacks and, for example, reduced night-time coughing.
Painkillers alleviate pain usually after around 30 minutes to one hour after taking the medicine. A course of antibiotics begins to alleviate the symptoms in a couple of days although the illness itself is not cured until after the course has ended. The effects of some medicines appear only after relatively long use. Some antidepressants, for example, lift your spirits only after a couple of weeks of use.
You can sometimes notice the effect yourself but not always
A painkiller's effect on alleviating a headache is easy to notice, as is a hydrocortisone cream's effect on relieving skin erythema and rash. However, the effect of some medicines can be noticed only with laboratory tests. The user cannot notice the cholesterol-lowering effect of cholesterol medicine, for example, in any way.
The effect of medicines must be assessed regularly: the use of an ineffective medicine should be stopped and changed to a different medicine.