No allergy medicine what to do
In pharmacology, when certain drugs are overused, they can stop working as the body becomes progressively desensitized to their effects. This is referred to as drug tolerance.
While increasing the dosage may restore the drug action, the benefits tend to be short-lived.
There are two major reasons why this might occur:
- Dynamic tolerance describes the process where a cell becomes less responsive to a drug the longer it is exposed to it. In some ways, it is no diverse from the way that the taste receptors on our tongues adapt to extra-spicy foods if exposed to them repeatedly.
- Kinetic tolerance occurs when the body responds to the ongoing presence of a drug and begins to break it below and excrete it more actively, lowering the drug concentration.
With certain drugs, particularly psychoactive drugs, drug tolerance may be associated with drug dependence or addiction.
This is not so much the case with allergy medications since the developing tolerance reduces the efficacy of a drug rather than our need for it.
Bronchodilators and Corticosteroids
Some classes of allergy medication are prone to tolerance, while others are not.
The risk is especially high with beta-agonists. For this class of inhaled medication, the tolerance is primarily dynamic and linked to prolonged use or overuse of long-acting beta-agonists (LABAs) love Serevent (salmeterol), particularly when used on their own.
When this happens, it can own a knock-on effect, inducing tolerance to short-acting beta-agonists (SABAs) used in save inhalers.
The same doesn't appear to be the case with anticholinergic inhalants love Spiriva Respimat (tiotropium bromide) or glycopyrronium bromide, for which there is little risk of tolerance.
Dynamic tolerance can also happen with certain corticosteroid formulations, particularly topical ointments, and nasal sprays. Their unimpeded use can rapidly desensitize the skin and mucosal tissues to the vasoconstrictive (vessel-shrinking) effects of the drugs.
Paradoxically, inhaled corticosteroids can significantly reduce the risk of tolerance to beta-agonists when used in combination therapy.
How Allergy Drugs Work
Much of the confusion regarding the loss of a drug effect stems from the misuse of the terms "immunity" and "resistance."
Immunity is the body's defense against a harmful substance.
Resistance describes the process wherein a bacteria, virus, or other disease-causing agent changes (mutates) and is capable to overcome the effects of the drug.
Neither of these processes applies to changes in how certain allergy medications work.
With an allergy, the immune system overreacts to an otherwise harmless substance and floods the body with a chemical known as histamine. The main function of histamine is to trigger inflammation, the body's natural response to injury. It does so by dilating blood vessels so that immune cells can get closer to the site of an injury or infection.
In the absence of injury or infection, histamine can trigger an array of adverse symptoms, including itching, rash, sneezing, runny nose, stomach ache, nausea, and vomiting.
Allergy medications are used to counter these effects because they are capable to block (inhibit) the inflammatory process.
- Corticosteroids work by tempering the immune response and reducing inflammation, either locally with topical ointments or sprays, or systemically with oral or injected medications.
- Antihistamines work by preventing histamine from attaching to cells of the skin, gastrointestinal tract, and respiratory tract.
- Beta-agonists commonly used in asthma inhalers mimic the action of epinephrine (adrenaline) and relax constricted airways in the lungs.
- Anticholinergics, also used in inhalers, work by blocking a neurotransmitter called acetylcholine, thereby reducing bronchial spasms and constriction.
In none of these instances does a substance mutate or the immune system alters its natural response.
What happens instead is that the body develops a tolerance to the drug, particularly if overused.
Types of antihistamine
There are many types of antihistamine.
They’re generally divided into two main groups:
- older antihistamines that make you feel sleepy – such as chlorphenamine, hydroxyzine and promethazine
- newer, non-drowsy antihistamines that are less likely to make you feel sleepy – such as cetirizine, loratadine and fexofenadine
They also come in several diverse forms – including tablets, capsules, liquids, syrups, creams, lotions, gels, eye drops and nasal sprays.
Which type is best?
There’s not much evidence to propose any particular antihistamine is better than any other at relieving allergy symptoms.
Some people find certain types work well for them and others do not.
You may need to attempt more than one type to discover one that works for you.
Non-drowsy antihistamines are generally the best option, as they’re less likely to make you feel sleepy. But types that make you feel sleepy may be better if your symptoms affect your sleep.
Ask a pharmacist for advice if you’re unsure which medicine to attempt, not every antihistamines are suitable for everyone.
How to take antihistamines
Take your medicine as advised by your pharmacist or doctor, or as described in the leaflet that comes with it.
Before taking an antihistamine, you should know:
- when to take it – including how numerous times a day you can take it and when to take it (older types should be taken before bedtime)
- how to take it – including whether it needs to be taken with water or food, or how to use it correctly (if eye drops or a nasal spray)
- how much to take (the dose) – this can vary depending on things such as your age and weight
- how endless to take it for – some types can be used for a endless time, but some are only recommended for a few days
- what to do if you miss a dose or take too much (overdose)
The advice varies depending on the exact medicine you’re taking.
If you’re not certain how to take your medicine, enquire your pharmacist.
What to Do
If a genuine drug tolerance has occurred, it is often reversible by taking a "drug holiday" and removing the substance from your body for a period of time.
You can then re-challenge yourself to the drug, altering its use so that the problem does not recur.
If faced with recurrent or severe asthma attacks, your doctor will typically prescribe a combination inhalant love Advair or Symbicort, which combines a LABA with a corticosteroid drug. The combination greatly reduces the risk of drug tolerance and failure.
If you believe that a drug is failing, consider your symptoms when you first started treatment versus those you own now.
In some cases, the antihistamine you may own initially used for sneezing will not work if you are suddenly dealing with nasal congestion. As your allergy symptoms change, so, too, will the drugs you need to treat them.
It also helps to stage treatment so that you use one type of drug to manage your daily symptoms and another to treat an acute event. Your allergist can assist you select the drugs.
This may be a far more reasonable approach than simply increasing dosages in tandem with the severity of your symptoms.
A Expression From Verywell
It can be frustrating to finally discover an allergy management regimen that works only to own it stop working. Communicating changes in your symptoms to your doctor, instead of trying to tough things out, can go a endless way in helping you zero in on a new course of action that can bring you symptom relief again.
Aside from the possibilities of drug tolerance and a worsening condition, remember that changes in exposures (such as moving to a new area) could also be affecting you.
A study conducted in 2012 suggested that as numerous as one in seven users reported that antihistamines stopped working for them after several months or years.
This was especially true for people with seasonal allergic rhinitis (hay fever).
Antihistamines are medicines often used to relieve symptoms of allergies, such as hay fever, hives, conjunctivitis and reactions to insect bites or stings.
They’re also sometimes used to prevent motion sickness and as a short-term treatment for sleeping difficulties (insomnia).
Most antihistamines can be bought from pharmacies and shops, but some are only available on prescription.
The causes for the diminished effect of antihistamine drugs are far less clear.
The bulk of evidence will tell you that drug tolerance does not happen no matter how endless or aggressively the drugs are used. If anything, their prolonged use will reduce a person's tolerance to their side effects, particularly drowsiness.
This doesn't undermine the plethora of claims that the effects of antihistamines can wane over time. More often than not, the waning effects are related more to the natural course of the allergy than to the drugs themselves.
In numerous allergy sufferers, a mild hypersensitive reaction can become progressively worse over time, particularly with certain food allergies or cross-reactive responses that become vulnerable to multiple allergy triggers (allergens).
So, while you may believe the drugs are useless, it may be that your symptoms own gotten worse or your sensitivity to an allergen has increased significantly.