Symptoms
Shortly after an injection, some patients may experience the following symptoms:
- Pallor
- Malaise
- Dry mouth
- Cold sweat
- Low blood pressure
- Drowsiness, dizziness, confusion
- Nausea
- Fainting, syncope (short-lasting circulatory collapse).
- Convulsions (seizures)
- ECG changes
- Falls, accidents
These disorders occur, for example, shortly after a vaccination, after parenteral administration of drugs, during acupuncture or blood sampling. It can cause a fear of injections or needles. Patients may recover somewhat within about 15 minutes, but the discomfort may continue for hours. Extremely rare fatal outcomes have been reported. It should be noted that the disorder may also occur with a time delay. Sensitive patients should therefore not drive and be accompanied. Patients may feel ashamed and use fewer medical services because of their anxiety. This can have a negative effect on their state of health. It is also problematic if patients should self-administer medications, such as insulins or low-molecular-weight heparins. Fear of needles is widespread. Figures in the range of 10 to 20% are found in the literature. It is both inherited and learned and often occurs in siblings.
Cause
The cause of the physical reaction is a drop in blood pressure. On the one hand, this is due to a decrease in heart rate (bradycardia) due to stimulation of the parasympathetic nervous system (“vagal”). On the other hand, there is vasodilatation of the arterioles triggered by a reduction in sympathetic tone (“vasal”). This is referred to as a vasovagal response.
Diagnosis
Affected patients usually have previous experience with their symptoms because they have developed the reaction before. They should be questioned and educated about this before the injection. Anaphylaxis must be ruled out when medications and vaccines are administered.
Nonpharmacologic treatment
- Patient should lie down
- Drink water
- Dextrose
- Pleasant atmosphere
Drug prevention and treatment
Anxiolytics and sedatives:
- Benzodiazepines are antianxiety and sedative agents that induce anterograde amnesia.
- 1st generation antihistamines such as hydroxyzine or doxylamine have sedative and anticholinergic effects.
Circulatory stimulant medications:
- Nicethamide lozenges
- Sympathomimetics such as etilefrine drops or epinephrine constrict blood vessels and increase blood pressure.
Anesthetics:
- Nitrous oxide (laughing gas) has sedative, weak anesthetic and anti-anxiety properties.
Local anesthetics:
- Such as lidocaine and prilocaine produce local anesthesia and can suppress the vasovagal response. They are also available as patches and creams.
Parasympatholytics counteract bradycardia:
- Atropine, scopolamine
Herbal medicines with sedative and anti-anxiety properties:
- Valerian
- Melissa
- Lavender
- Cannabis, cannabidiol
- Passionflower
- Kava
Oxygen:
- For emergency treatment
Prevention
Because of the drop in blood pressure, injections or blood sampling should be done while sitting or, even better, lying down. Stimulate the muscles of the legs. If a chair is used, it must be possible to fold it down backward. The patient must not fall in case of fainting.
- Patient education: This is a common and usually harmless problem.
- Empathic and respectful treatment of those affected.
- Giving the patients time.
- Relaxation techniques.
- Avoid unnecessary injections. For some injectables are now also available alternative forms of administration.
- Distraction.
- Stickers are available in stores to cover the needle for children.
- Deconditioning by repeated exposure.
- Being accompanied by a partner, relative or friend.