Understanding Medications for Seasonal Allergies

More than 50 million Americans suffer from seasonal allergies and spend billions of dollars on over-the-counter and prescription medications for symptom relief.

You may be curious why you are more susceptible to discomfort from pollen than another. The problem starts with the immune system that is active in your nose1, eyes, and lungs.  This picture helps to explain what is happening in the nose.

When you breathe in pollen from a flower or weed, tiny particles from the pollen activate switches in the body (step 1 in the picture). The medical term for a “switch” is a “receptor.” This is the first step in a system designed to remove harmful substances from your body. The problem arises when the system overreacts. It is this overreaction that results in runny nose, nasal stuffiness, sneezing and itching. After a cell in the nose detects pollen, it turns on the release of several substances included histamine (step 2). Histamine does many things. When it connects with “histamine receptors” in the lining of the nose (step 3), it triggers runny nose and nasal congestion (step 4).  Histamine also activates nerves in the nose.  This results in itching and sneezing (step 5).

Medications such as “antihistamines” help to decrease these symptoms. Antihistamine medications connect to “histamine receptors” and block the effect of histamine.  This effectively turns off the histamine response (step 6).  Antihistamine medications such as Benadryl, Zyrtec and Allegra work in this manner.  

Another type of medication for nasal stuffiness from allergies is a steroid spray. Steroid medications also stick to receptors inside many cells of the body. In cells of the immune system, steroids slow down how well the cells work. In step 2 (see the picture above), immune cells produce histamine and other chemicals. Nasal steroids cause the cells to make less of the chemicals like histamine. The end result is an alleviation of the symptoms – runny nose, nasal congestion, itching and sneezing.

Antihistamines and nasal steroids work very well and have provided millions of people with symptom relief. But like every drug, there are side effects. One important side effect of antihistamines is sleepiness. This bothersome side effect happens because histamine receptors are also in the brain, and they plan an important role in brain activity. The next picture gives you an idea of what happens when an antihistamine medication gets into the brain.

The first step is connection of histamine to histamine receptors in the brain (step 1). One of the effects of this switch is to activate brain responses that maintain alertness and control the sleep-wake cycle (step 2).  When an antihistamine drug gets into the brain, this switch is turned off resulting in sleepiness (step 3). 

It was a major advance when medications like Zyrtec and Allegra were invented. They are less likely to reach the brain. Because of this, they work very well for allergy symptoms in nose, eyes, and skin, but much less commonly cause drowsiness.

Nasal steroids are also less likely to have effects on the brain. Steroids taken by mouth can have affects all over the body and this short blog cannot explain all of the side effects. However, nasal steroids tend to be tolerated very well because most of the medication stays in the nose and works on the immune system in that location. Much less of the steroid gets access to other regions of the body such as the brain.

It is important to understand how these medications work since many can be purchased without a prescription. Unfortunately, there are thousands of products that include medications to control runny nose, itchy eyes, and itchy skin. Many of these products contain antihistamines that do cause drowsiness. You want to be sure about this before you take a new over the counter product.  You would not want to drive or operate machinery at work when taking some of these over the counter medicines. For elderly people, taking these products can put them at risk of a fall and breaking a hip.

Freemedicationreview.org has made a program freely available on the web to let you know when medications you take for allergy symptoms can increase your risk of sleepiness. The use of this program is anonymous and no registration is required.

Click on the link below to start your free medication assessment. This will give you important information for a discussion with your doctor to make sure that all medications taken, including over the counter, do not put you at an increased risk of an accident.


By: Jeffrey Huth, M.D., Ph.D.

July 7, 2019


1.        Wheatley LM, Togias A. Clinical practice. Allergic rhinitis. N Engl J Med [Internet] 2015;372(5):456–63. Available from: http://www.ncbi.nlm.nih.gov/pubmed/25629743

Disclosure Information:

DO NOT STOP MEDICATIONS OR CHANGE HOW OR WHEN YOU TAKE THEM WITHOUT FIRST CONSULTING A HEALTH CARE PROVIDER. This information is in no way designed or intended to replace personal consultation with a qualified physician, pharmacist, or other healthcare professional. 

Copyright 2019 FreeMedicationReview.org, a division of ScopiaRx LLC

Safety of Multiple Medications – Polypharmacy

If you have ever paid attention to a commercial on a new drug, then you have undoubtedly heard the term “drug interaction.” To most people and many doctors, a drug interaction is limited to two drugs. Serious drug interactions are usually avoided because your doctor uses a computer program that checks for those before they write your prescription.

The problem is that 39% of the population over the age of 65 takes more than five drugs.1 When this happens, many drugs, often more than three, can interact. The medical term for taking many medications is polypharmacy. For the most part, polypharmacy risks are not checked by the software that doctors use when they write a new prescription, and the risks can be severe. Many drugs can change your mental capacity and cause tiredness, dizziness, sleepiness and/or decreased coordination. Taking 3 or 4 drugs that do this is similar to drinking too many alcoholic beverages. You wouldn’t do that and drive, but many people may unwittingly do that and drive, take stairs, or are left unchaperoned at home without knowing that a trip and fall may result.

Another serious concern when taking many medications is kidney health. How medications affect the kidneys should be monitored carefully when a person is not healthy. Studies have shown that this is a major concern when a person is hospitalized2 or resides in a nursing home.3 A vicious cycle can develop when poor health is combined with polypharmacy. The kidneys may be stressed from poor health, and this is then worsened by many types of medications. Then when kidneys are working poorly, some drugs are not eliminated from the body as quickly.  If the dose is not lowered, then a drug overdose can occur.  The overdose can then put more stress on the kidneys, worsening the situation.

Many side effects are more likely to happen when one takes multiple medications, and there is no way to talk about all of the concerns in one short blog.  But there is a third risk that is very common that may be unrecognized by your doctors when you take multiple prescription medications and over the counter medications. The risk of bleeding is an important concern for many people.  

Particularly if you take a blood thinner for a condition such as history of blood clots or atrial fibrillation, known as “A-Fib”, polypharmacy should be monitored.  Studies have shown that taking more than one drug that causes thinning of the blood increases the risk of a stroke (bleeding stroke) or severe gastrointestinal bleeding. Many people take a prescription blood thinner and often are instructed to take a daily aspirin.  All of this is fine when monitored by your primary doctor or a cardiologist. But if you also take ibuprofen, or naproxen, or Advil, or Aleve, let them know.  These drugs also increase the risk of bleeding and can tip the balance towards a risk of severe bleeding that is too high.4 

Let your doctors know about all of the over the counter medications that you take. Many of cold and flu products contain ibuprofen or high doses of aspirin, which is not obvious from the package information. The last thing you and your doctor want is for you to be on a blood thinner, take 81 mg daily aspirin, and then take 325 to 800 mg of aspirin in a cold and flu tablet.   

When polypharmacy occurs it is important to closely work with your doctors to make sure that the possible side effects are under control. Communication is important because when several doctors are writing prescriptions for you, they each may not have a complete list of your medications. When they don’t know, they cannot help you. And dangerous interactions can result if a new prescription is given in the absence of knowing all of the other medications that you take.

There are ways to safety manage polypharmacy, but it is important to work with your doctors and pharmacists. Do not make changes on your own because serious health risks may result. Your doctor or pharmacy may ask you to take medications at different times during the day or lower the dose of medications. Sometimes the wise decision is to change or stop a medication.

Medications and side effects are complicated. All of this can be daunting and frustrating manage for either your or a loved one. To get you started on making a list of questions for the doctor and to see if polypharmacy potentially affects you, you can use a free application on the web to evaluate some of the most important risks of polypharmacy: fall risk, bleeding, and kidney injury.

But remember, don’t manage this by yourself. Talk to your doctors and pharmacist about all of your concerns and work with them to fine tune your medications. They can help you find the best balance between health benefits and quality of life.

Contributed By Jeffrey Huth, M.D., Ph.D.


1.        Kantor ED, Rehm CD, Haas JS, Chan AT, Giovannucci EL. Trends in Prescription Drug Use Among Adults in the United States From 1999-2012. JAMA [Internet] 2015;314(17):1818–31. Available from: http://www.ncbi.nlm.nih.gov/pubmed/26529160

2.        Chang Y-P, Huang S-K, Tao P, Chien C-W. A population-based study on the association between acute renal failure (ARF) and the duration of polypharmacy. BMC Nephrol [Internet] 2012;13:96. Available from: http://www.ncbi.nlm.nih.gov/pubmed/22935542

3.        Dörks M, Herget-Rosenthal S, Schmiemann G, Hoffmann F. Polypharmacy and Renal Failure in Nursing Home Residents: Results of the Inappropriate Medication in Patients with Renal Insufficiency in Nursing Homes (IMREN) Study. Drugs Aging [Internet] 2016;33(1):45–51. Available from: http://www.ncbi.nlm.nih.gov/pubmed/26659732

4.        Dreischulte T, Donnan P, Grant A, Hapca A, McCowan C, Guthrie B. Safer Prescribing — A Trial of Education, Informatics, and Financial Incentives. N Engl J Med [Internet] 2016;374(11):1053–64. Available from: http://www.nejm.org/doi/10.1056/NEJMsa1508955