Can Diabetics Take Benadryl?

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Many of us suffer from seasonal allergies. When summer grasses and trees release pollen into the air, we may develop an allergic reaction like a stuffy nose or watery eyes. We'll soon be looking for allergy medications to control the symptoms.

But if you are a person with diabetes, there are precautions you should follow when taking any new medications. Since the goal is to keep your blood sugar levels low, any increase could be dangerous. The good news is that antihistamines for allergy symptoms rarely impact blood sugar levels.

Generally, Benadryl is safe for people with diabetes who are looking for oral medications to treat allergies. But be aware that you should pay attention to your body whenever you mix medications. And it's a good idea to test your blood sugar levels before and after taking new meds.

Also, take note that none of this is medical advice. The body's immune system and normal blood sugar level is different for everyone. Contact your healthcare provider for guidance about taking over-the-counter allergy medications.

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Why Do People With Diabetes Have a Higher Risk of Catching a Cold or the Flu?

A person with type 1 diabetes who maintains healthy glucose control has the same likelihood of contracting a common cold or influenza as a person without diabetes. But a person who doesn't monitor their blood glucose levels may be more susceptible to getting sick.

People suffering from Diabetes often catch colds due to their weakened immune systems. Diabetes affects not only the heart, brain, and kidneys, but also the immune system. Long-term, uncontrolled diabetes impairs the immune system and increases susceptibility to disease and infection.

Infections in the respiratory tract, skin and soft tissues, and gastrointestinal tract are more prevalent in individuals with diabetes. In addition to being more rampant, these infections appear to have a poor therapeutic response.

What Happens if a Diabetic Catches a Cold?

If you have received a diabetes diagnosis, your body is already under a lot of stress from the extra work it's doing to regulate your blood sugars. The last thing you need is for cold or flu germs and medications to increase your blood sugar.

While your body is busy fighting the germs and viruses that are causing the illness, it secretes substances into the bloodstream that increase blood sugar and inhibit your insulin's ability to lower blood glucose levels.

Benadryl or other antihistamines rarely impact blood sugar levels directly. Nevertheless, if you take medication that causes drowsiness, you may miss signs of high or low blood sugar. Ask your pharmacist about antihistamines without sedative effects, and if they are approved to take with your diabetes meds.

There are other medications that can raise your blood glucose or cause allergic reactions. They include corticosteroids, diuretics, some blood pressure drugs, and certain antidepressants, among others. Anyone with diabetes who is taking these medications should inform their healthcare provider.

Should a Diabetic Worry About Ketoacidosis?

When you're suffering with a cold, the body releases hormones to combat the infection. This makes it difficult for you to use insulin effectively, and your blood sugar levels may rise. If you have type 1 diabetes and your blood sugar levels become difficult to control, you may develop ketoacidosis.

Typically, people with type 1 diabetes with prolonged high blood sugar, missed diabetes medications, or even a severe illness or infection can develop ketoacidosis. Diabetic ketoacidosis can also occur in those with type 2 diabetes. DKA develops when the body lacks sufficient insulin to enable glucose into cells for energy production.

If you are suffering from diabetes and also taking oral medications to control diabetes and high blood pressure, taking over-the-counter medicine for hay fever or seasonal allergies may affect blood glucose levels. Allergies alone may not alter glucose levels, but allergy treatments can. There are many over-the-counter and prescription drugs that can affect blood sugar levels.

Does Illness Raise Blood Sugar Levels?

Illnesses, allergy symptoms, and infections can bring on dangerously high blood glucose levels. Extra glucose is released into the bloodstream as part of the body's defense mechanism for combating disease and infection. When your body releases hormones to combat a disease, it also increases your blood sugar and insulin requirements.

Does Illness Interfere with Insulin Resistance?

When suffering from the flu or a severe bacterial illness, or not getting enough sleep while ill, the body will release stress chemicals. These hormones might cause the liver to release glucose that has been accumulated. Your body will require much more insulin on these days.

Certain illnesses can produce the opposite effect. If you don't feel like eating or if you have nausea or vomiting while taking insulin as usual, your blood sugar levels may get too low. When dealing with an illness, blood sugar levels can be quite variable.

What Kind of Cold and Flu Medications Can You Take If You Have Diabetes?


Those with type 1 or type 2 diabetes whose immune systems are weakened by prescribed drugs may have difficulty fighting off colds and flu viruses.

People suffering from diabetes and who get a cold or the flu should take diabetic medications as directed by their physicians. As their bodies fight the infection from the common cold or flu, their blood sugar can spike or drop throughout the day. Sick diabetics must monitor their blood sugar levels more frequently.

Pain and Fever Reducers

Acetaminophen is used in Tylenol and many other cold and flu remedies. Overuse, or taking too much at once can be damaging to your liver and kidneys.  If you have diabetes-related kidney issues, consult your healthcare professional before taking this medication.

Ibuprofen is a non-steroidal anti-inflammatory medication. People suffering from diabetes who also have a with liver and/or kidney disease should use this with caution. Insulin and diabetes medicines may be more effective at reducing blood sugar at higher doses.

Naproxen is another non-steroidal anti-inflammatory medication. You should not use naproxen if you have serious heart disease, kidney disease, or liver disease. Insulin and diabetic meds may raise the risk of low blood sugar if you are taking higher doses.


Popular decongestants phenylephrine and pseudoephedrine are generally discouraged for those with diabetes. They constrict blood arteries and reduce swelling to decrease nasal fluid and discharges. Ask your healthcare provider to recommend a decongestant that doesn't interfere with your diabetic drugs if you feel you need one.

Cough Suppressants

Use a cough suppressant to alleviate a dry, hacking cough, and if your chest is full of phlegm, try an expectorant to thin and loosen the phlegm and mucus. This makes it easier to discharge mucus from the airways when coughing.

While cough suppressants are generally safe for people with diabetes, make sure whatever brand you buy is sugar free. The safest action you can take for a cough is to gargle with warm salt water.


Antihistamines may not affect diabetes directly, but some can produce sleepiness, making it more difficult to recognize the signs of high and low blood glucose levels. If you are concerned about diabetes self management, non-drowsy antihistamines are a preferable option.

Nasal Sprays

If your nasal passages are blocked, runny, or dry, you may want to try using nasal sprays. Over-the-counter decongestants are available in the form of nasal spray, nose drops, tablets, and liquid formulations. Several over-the-counter nasal decongestants have a warning label for diabetics against use unless they are approved by your physician.

What Ingredients in Cold Medication Interact with Insulin Medication?

You wouldn't think cold medicine, Benadryl meds, or other oral medication would contain substances that affect your blood glucose levels, but there are some that do. Alcohol and sugar are non-drug substances that may be included in the cold and flu medication you are taking. Both sugar and alcohol can increase blood sugar levels.

Sugar and alcohol are not the main active ingredients, but occasionally there could be enough to upset your glucose levels.


Any medication with sugar as an ingredient could significantly increase your blood sugar levels. The good news is modern cold medication contains very little sugar. If a drug affects your blood sugar, your doctor may advise you to discontinue use. If your doctor wants you to continue using the drug, they may temporarily adjust your insulin or diabetes medicine dosage.

The more medications you take, the higher your risk of experiencing adverse effects. A small rise in blood sugar produced by a single medicine may be okay. Taking too many drugs that elevate blood sugar may result in a dangerously high sugar level.


Some over-the-counter cough medications contain alcohol, although these are being phased out in favor of alcohol-free formulas.

If you are using medicine that contains alcohol, it can interfere with the effectiveness of certain diabetes medications, putting you at risk for hypoglycemia or hyperglycemia, depending on the medication. Check with your doctor to be sure.

Can Cold Medication Cause a Diabetic to Have Low Blood Sugar Levels?

While people with diabetes are generally concerned with high blood sugar levels, there are some cold, flu, and allergy medications that can lower blood sugar.

While you are sick, it is a good idea to check your blood sugar numerous times during the day. This is true regardless of the medication you are taking along with your diabetes meds, like a decongestant, an antihistamine, a steroid, or any other kind of drug.

Can a Diabetic Take Benadryl?

Yes, if you're suffering from allergies or hay fever, Benadryl is okay to take under your doctor's supervision. However, Benadryl may cause drowsiness and interfere with your everyday activities, such as your diabetes management. Antihistamines, such as the widely used allergy medication Claritin, do not raise blood sugar levels.

When Should I Contact My Doctor?

A diabetic should always consult their doctor before taking any new medications. If you take diabetes medication, you'll need to know if the new meds are interfering with your blood sugars.

In the spring and summer, when weeds generating hay fever particles are all around you, and you need a way to treat allergies with meds that won't affect blood glucose, over-the-counter common allergy medication like Benadryl is okay to use with your doctor's guidance.


Diabetics with a cold or the flu should take their diabetic medications as directed by their physicians. As their bodies fight the infection from these common aliments their blood sugar can spike or drop throughout the day. Sick diabetics should check their blood sugar levels frequently and notify their doctor if they experience extreme spikes or dips of blood sugar.

The best approach for diabetics to prevent colds and the flu, and associated complications is by receiving the seasonal flu vaccine each year, and allergy shots in the spring. Avoiding contact with sick people who are coughing, sneezing, or have postnasal drip is recommended.

As a diabetic, your primary focus is to control your blood sugar levels. After that, address any other illness with the help of your doctor.