In general, the daily use of allergy tablets or antihistamines is a safe and effective way to prevent the symptoms of allergies. Over time, however, long-term use of allergy tablets can lead to side effects such as fatigue, headaches, dry mouth, dry eye syndrome, and even skin dryness.
Daily allergy tablets (antihistamines) are safe, but over time they may become less effective because of tolerance or the worsening of a person’s allergy symptoms.
Daily allergy tablets may cause side effects such as dryness.
Daily allergy tablets may work better with the addition of other medications such as nasal sprays.
Daily allergy tablets or liquids can be taken for allergy immunotherapy, which is the only treatment that actually treats the immune system.
For these reasons, it is best to take allergy tablets only when you need to prevent allergic reactions, such as when the seasonal pollen counts decline. It is possible that daily use of allergy tablets may indicate a more serious allergy and further allergy evaluation and management should be undertaken.
Long-term allergy tablet use can also cause the medication to be less effective over time. This could be because of changes in your allergy sensitivity, environmental changes, or stress.
Another phenomenon that is possible with long-term antihistamine use is tachyphylaxis. Tachyphylaxis is when the antihistamine becomes less effective, or you build a tolerance to the drug. This is especially true for the older sedating antihistamines which can become addictive because the person continues to take the medicine expecting higher doses to begin working.
Another allergy tablet or oral formulation of allergy treatment is allergy immunotherapy. Traditionally, allergy immunotherapy is performed by allergy shots or subcutaneous immunotherapy (SCIT) (shots at the skin surface).
These are the only treatments that actually change the immune system. New formulations consist of allergy drops under the tongue, allergy tablets, or even toothpaste with allergy immunotherapy that are particularly popular with children.
Only take antihistamine allergy tablets when you think you need them
The best method of dealing with allergies is to take allergy tablets on an as-needed basis. This means using one of the popular non-sedating kinds, although in some cases the sedating ones can be useful, too.
Some people know that they are going to need help with their allergies when it comes to a certain time of year or if they are exposed to something they know will trigger an allergic reaction such as being around a dog or cat or being stung by a bee in the yard.
Using over-the-counter nasal steroid sprays is a good addition to antihistamine allergy tablets. Together the nasal spray and antihistamine may work better than either one alone.
Some allergy tablets will have both an antihistamine and a decongestant medication. Decongestant use should be minimized since it can elevate blood pressure, cause eye problems such as glaucoma, or worsen symptoms of thyroid disease. They can also make the person feel jittery or have difficulty sleeping.
What should I do if I think I need allergy tablets long-term?
If this is your thought, you may need further allergy evaluation and treatment. It is possible that the allergy tablets are providing only partial or temporary relief.
Keep in mind while taking allergy tablets every day you may experience symptoms even if they are non-drowsy. People can still have drowsiness over the long term and these other symptoms:
- Dry eye, blurry vision, trouble focusing, worsening of itchy eyes.
- Dry mouth which can cause gum and tooth discomfort.
- Poor appetite, stomach upset.
- Nervousness, insomnia.
It is also important to consult with your healthcare professional or pharmacist about any possible interaction of the allergy tablet with any current medication that you take. In some cases, antihistamines can interfere with other medications like antibiotics and cause serious problems.
Can the allergy tablet I take every day stop working and why?
While this phenomenon called tachyphylaxis or tolerance may be more pronounced with the older, sedating antihistamines, it can still occur with the newer medications on the market.
Antihistamines bind to histamine receptors on the surface of cells. In addition, the receptors can also signal without antihistamine binding. This means that even though a person is continuing to take an antihistamine, there can be persistence of allergy symptoms over time.
Some doctors recommend alternating between different antihistamines to prevent this type of tolerance to particular medications. However, most recent studies suggest that tolerance is much less likely to occur with the newer antihistamines even with daily use.
Still, many people feel the antihistamines stop working. The explanation may be because the person is experiencing worsening allergy symptoms instead of the antihistamines not working. In these instances, it is a sign to have an allergy evaluation and intensify the allergy treatment protocol.
Are there daily allergy tablets or drops I can take instead of allergy shots?
These are likely neither antihistamines nor combinations of antihistamines and decongestants. They are allergy immunotherapy and are very useful for those people who feel their daily allergy tablets are no longer enough to control their symptoms.
After extensive allergy testing, it is helpful to determine what a person is allergic to and to what degree. The principle of allergy immunotherapy is desensitization which means that the person is given tiny doses of what they are allergic to, and their body increases its immune system response, thereby decreasing their allergy symptoms.
Allergy immunotherapy has been used for many years with great success. A personalized formula is designed for each person with allergies to accommodate their particular allergy profile.
Allergy immunotherapy is usually performed with traditional allergy shots under the skin. Some newer versions for children are done by pressing the skin with liquid immunotherapy as opposed to using a needle.
Another method that has become increasingly popular is sublingual immunotherapy. This means that allergy immunotherapy is custom mixed and used under the tongue in liquid form. Some formulations are small dissolvable tablets. The formulations have been mixed in mouthwash or toothpaste as well which have become very popular with children and teenagers.
In the case of allergy immunotherapy whether in tablet form or otherwise, the treatment takes time just like allergy shots. It can take months for any measurable effect and then there is maintenance dosing that is required.
- Mayo Clinic. Mayo Clinic A and A: OTC Allergy Medications May Not Be Best Treatment Option.
- Mayo Clinic. Allergy medications: Know your options.
- Cleveland Clinic. What Allergy Medication Works Best?
- Johns Hopkins Medicine. Sublingual Immunotherapy.
- Journal of Investigative Allergology and Clinical Immunology. Comparative pharmacology of the H1 antihistamines.