How pseudoephedrine works
Pseudoephedrine ensures that the stress hormone noradrenaline – a messenger substance of the sympathetic nervous system (part of the autonomic nervous system) – is increasingly released by nerve cells and only reabsorbed with a delay. This increases and prolongs its effect – the sympathetic nervous system is stimulated.
The autonomic nervous system of the human body can be divided into two different parts according to function:
- The sympathetic nervous system activates the body: the heart beats faster, the bronchi of the lungs and the pupils dilate, the body is set to perform.
- The counterpart to this is the “parasympathetic nervous system” (parasympathetic nervous system), which specifically promotes the regeneration of the body: Digestion is stimulated and the heartbeat slows down.
In therapeutic doses, the effect of pseudoephedrine is limited to the mucous membranes of the nasopharynx and bronchi. Stimulation of the sympathetic nervous system causes the blood vessels to contract (thus reducing swelling of the mucous membrane) and the bronchi to dilate, which improves breathing.
Absorption, breakdown and excretion
It reaches the mucous membranes of the upper respiratory tract and the lungs via the blood. The highest blood levels can be measured after two hours.
Pseudoephedrine is partially broken down in the liver, resulting in the formation of other active metabolites. It is excreted via the kidneys in the urine. About five to eight hours after ingestion, half of the active ingredient has left the body.
When is pseudoephedrine used?
Medication containing pseudoephedrine is used for the symptomatic treatment of
- Runny nose and colds with nasal congestion
- allergy-related irritation and inflammation of the nasopharynx
- Swelling of the Eustachian tube (connecting passage between the nasopharynx and middle ear)
It should only be used for a short time (a few days). With prolonged use, the body becomes accustomed to the active ingredient and its effectiveness decreases.
How pseudoephedrine is used
Pseudoephedrine is usually offered in combination preparations together with other active ingredients.
In combination with pain-relieving active ingredients such as ibuprofen and acetylsalicylic acid (ASA), the active ingredient is mainly used for colds. Combination preparations with anti-allergic active ingredients such as triprolidine, desloratadine or cetirizine are used to treat allergies such as hay fever.
The tablets or drinking granules are taken throughout the day, independently of meals. A total daily dose of 240 milligrams of pseudoephedrine should not be exceeded.
What are the side effects of pseudoephedrine?
The occurrence of adverse drug reactions with pseudoephedrine is dose-dependent. Especially at high doses, side effects due to activation of the sympathetic nervous system occur more frequently, such as loss of appetite, increased blood pressure, palpitations, insomnia, urinary retention and skin reactions such as rashes, redness and itching.
What should be considered when taking pseudoephedrine?
Contraindications
Pseudoephedrine must not be used if:
- Diseases of the heart (such as coronary heart disease)
- cardiac arrhythmia
- Hyperthyroidism (hyperthyroidism)
- Prostate enlargement with residual urine formation
- High blood pressure (hypertension)
- Simultaneous treatment with monoamine oxidase inhibitors (MAO inhibitors; against depression) or linezolid (antibiotic)
- Glaucoma (glaucoma)
Interactions
The combination with other active substances that stimulate the sympathetic nervous system can lead to serious side effects, which primarily affect the cardiovascular system.
Pseudoephedrine can weaken the effect of high blood pressure medication.
Age restriction
Pseudoephedrine can be used in children from the age of twelve.
Pregnancy and breastfeeding
As pseudoephedrine can cross the placental barrier, it should not be used during pregnancy. In pregnant women, pseudoephedrine can also cause reduced blood flow to the placenta, which puts the child at risk.
Pseudoephedrine passes into breast milk in small quantities. To date, however, there have been no reports of side effects in breastfed infants.
How to obtain medication with pseudoephedrine
Combination preparations containing the active ingredient pseudoephedrine are available in pharmacies in Germany, Austria and Switzerland and can be obtained without a prescription, provided that the other active ingredient is also available without a prescription.
This also applies to painkillers and older anti-allergic active ingredients. Preparations in which pseudoephedrine is combined with newer anti-allergic active ingredients require a prescription.
How long has pseudoephedrine been known?
Pseudoephedrine was discovered in 1885 by the Japanese chemist Nagayoshi Nagai together with the chemically very similar active ingredient ephedrine. In the mid-1920s, the active ingredients were then marketed as a remedy for asthma.