Antihistamines could be why you feel tired
Anyone who suffers from hayfever will know how hard it is to function normally during the pollen season.
This is partly due to the relentlessness of their symptoms.
It can also be a side effect from taking anti-histamines.
Why is hayfever getting worse?
NHS data suggests that 20% of the population in the UK suffer from hay fever and it’s the cause of an estimated 3.2 million sick days annually.
In recent years hayfever sufferers frequently tell me their symptoms are much worse than they used to be.
This has been shown to be caused by climate change and pollution. [Link to find out more from related research]
- Pollution has been proved to raise the pollen count
- The pollen season is lasting longer due to climate change
Hay fever is usually hereditary, and is the result of an intelligent immune response that’s over-reacting.
When the histamine response is over-active, it’s called an allergy.
Is histamine a hormone?
Hormones are chemical messengers made by glands in the endocrine system.
Histamine plays a part in body functions regulated by the endocrine system, but it isn’t a hormone.
It’s actually a central nervous system transmitter with many functions, including:
- cell growth
- wound healing
- endocrine balance
- sleep-wake cycle
Histamine also has the ability to stimulate blood flow to the mucus membranes as part of an overall immune response to physical triggers such as pollen.
This is the root cause of sneezing, tears, and mucus production – an intelligent response designed to move allergens away from the body where they are causing irritation.
What are antihistamines?
Antihistamines are drugs commonly used to treat allergies, and also travel sickness, colds, flu and insomnia.
They were first discovered in 1937, but it wasn’t until 1942 that the first drug was introduced for medical use.
Antihistamines can be bought without a prescription to provide relief from nasal congestion, sneezing or hives caused by pollen, dust mites or animal allergies.
Common UK drugs containing antihistamine:
- Lemsip Max – colds/flu
- Night Nurse – colds/flu
- Stugeron – travel sickness
- Nightol – insomnia
- Piriton – allergy
- Piriteze – allergy
- Benadryl – allergy
- Clarityn – allergy
- Fexophendine – allergy
The earliest forms of antihistamin drugs are known as First Generation Antihistamines (FGA).
They work by binding to histamine H1 receptors in mast cells and smooth muscle in the body, as well as the tuberomammillary nucleus – the histaminergic nucleus located in the part of the brain called the hypothalamus.
The histaminic nucleus is the source of histamine pathways in the human brain, and is also involved with the control of learning, memory, sleep and energy balance. [Link to medical report]
In simple terms, early antihistamines cross the ‘blood-brain’ barrier into the central nervous system, causing problems such as drowsiness, and disrupted sleep leading to the impairment of adults to work and drive.
When used at night, FGA also reduce REM sleep. The residual effects of poor sleep, including the impairment of attention, working memory and motor performance are still present the following morning. [Link to medical report]
Despite these risks, FGAs are still used in Piriton (a liquid antihistamine used for allergies in children), Benadryl, Stugeron (travel sickness and anti-nausea drugs) and Nytol (insomnia relief drug).
Occasional use of FGAs may be useful in certain cases, but routine, repeated or on-going use is not recommended.
The detrimental effects of FGA antihistamines on learning and examination performance in children and on the impairment of the ability to drive, use machinery and fly aircraft, led to the introduction of Second Generation Antihistamines (SGA) being developed in the 1980s.
SGA drugs are considered ‘minimally’ sedating because they have a ‘limited’ penetration of the blood-brain barrier. They work differently, by stabilising histamine receptor cells.
The most recently developed antihistamine drugs work slightly differently.
Desoratadine is the most likely to cause somnolence (drowsiness) in certain people.
Why antihistamines don’t solve the hayfever problem
Antihistamines are most helpful for reducing itching and nasal discharge but don’t always have much impact on congestion. They have limited use in treating eye symptoms caused by allergies.
Many adults I see who take antihistamines regularly report extreme fatigue and brain fog. Memory issues and poor concentration make it hard for them to function at work. This is clearly a side effect, even from ‘non-drowsy’ drugs.
This is because certain antihistamine drugs (desloratidine) are metabolised through the liver. If taken frequently, or alongside other drugs metabolised through the liver, this can be a further cause of tiredness and irritability.
Homeopathy is different
Homeopathy treatment does not suppress symptoms in the way that antihistamines do.
A wide range of homeopathic medicines are available to support the immune system in finding more balance. We also use preparations derived from pollens to help reduce sensitivity. [Related post]
If you are concerned about the side effects of antihistamines and want to find out more about how homeopathy could help you, feel free to get in touch.