Humulin R has possible interactions with alcohol, some other drugs, and certain supplements. Examples include fluoxetine (Prozac) and prednisone (Rayos). Talk with your doctor to avoid potentially harmful effects from Humulin R interactions.
Humulin R is prescribed to help manage blood sugar levels in adults and children with type 1 or type 2 diabetes.
An interaction occurs when one substance causes another substance to have a different effect than expected.
Humulin R comes as a liquid solution in two forms, and they have the same interactions. The forms are:
- Humulin R U-100, which is given as a subcutaneous injection or intravenous (IV) infusion (an injection into your vein over a period of time)
- Humulin R U-500, which is given as a subcutaneous injection
Unless stated otherwise in this article, “Humulin R” refers to both forms.
By learning about possible Humulin R interactions, you can work with your doctor to ensure Humulin R will be safe and effective for you. For additional information about Humulin R, including details about its uses, see this Humulin R overview article.
Note: Humulin R U-100 can also be purchased over the counter (OTC) without a prescription.
Before you start treatment with Humulin R, tell your doctor and pharmacist about any prescription, OTC, and other medications you take. By sharing this information with them, you may help prevent possible interactions.
To learn whether Humulin R interacts with supplements, herbs, or vitamins, see the “Humulin R and other interactions” section.
If you have questions about drug interactions that may affect you, ask your doctor or pharmacist. They can tell you more about drugs that interact with Humulin R and what medications should not be taken with this insulin.
Here’s a table of drugs that can interact with Humulin R. Keep in mind this table doesn’t include all drugs that may interact with Humulin R. Some of these interactions are described in detail in “Drug interactions in depth.”
| Drug class or drug name | Drug examples | Interaction result with Humulin R |
|---|---|---|
| pioglitazone (Actos) | — | may increase the risk of water retention or low blood sugar |
| fluoxetine (Prozac) | — | may increase the risk of low blood sugar |
| clonidine (Catapres, Nexiclon XR, others) | — | may hide symptoms of low blood sugar or affect how well Humulin R manages blood sugar |
| certain antipsychotics | • aripiprazole (Abilify, Aristada, others) • brexpiprazole (Rexulti) • olanzapine (Zyprexa) | may affect how well Humulin R manages blood sugar |
| other diabetes drugs | • glyburide (Diabeta, Glynase) • metformin (Glumetza) • sitagliptin (Januvia, Zituvio) | may increase the risk of low blood sugar |
| angiotensin converting enzyme (ACE) inhibitors | • benazepril (Lotensin) • lisinopril (Qbrelis, Zestril) • ramipril (Altace) | may increase the risk of low blood sugar |
| angiotensin II receptor blockers (ARBs) | • candesartan (Atacand) • losartan (Cozaar) • olmesartan (Benicar) | may increase the risk of low blood sugar |
| thyroid hormone drugs | • desiccated thyroid (Armour Thyroid) • levothyroxine (Unithroid, Synthroid, others) • liothyronine (Cytomel) | may affect how well Humulin R manages blood sugar |
| corticosteroids | • dexamethasone (Hemady) • methylprednisolone (Medrol) • prednisone | may affect how well Humulin R manages blood sugar |
| beta-blockers | • carvedilol (Coreg, Coreg CR) • metoprolol (Lopressor, Toprol XL, others) • propranolol (Hemangeol, Innopran XL, others) | may hide symptoms of low blood sugar or affect how well Humulin R manages blood sugar |
In some cases, factors or conditions could prevent your doctor from prescribing Humulin R due to the risk of harm. These are known as contraindications. Below are the contraindications of Humulin R.
Note: Before you start treatment with Humulin R, it’s important to tell your doctor if these contraindications apply to you. They can determine whether to prescribe this insulin and tell you more about what to avoid when taking Humulin R.
Having an episode of low blood sugar
Doctors will advise you not to administer Humulin R during an episode of low blood sugar. Using Humulin R during this time could cause severely low blood sugar, which can be life threatening.
Talk with your doctor about the typical blood sugar range that’s safe for using Humulin R. They can also tell you when it’s safe to resume Humulin R treatment after an episode of low blood sugar.
Having had an allergic reaction to Humulin R or any of its ingredients
If you’ve had an allergic reaction to Humulin R or any of its ingredients, your doctor will likely not prescribe Humulin R. Using the drug could cause another allergic reaction. You can ask them about other treatments that may be better choices for you.
Doctors will likely advise you to avoid or limit alcohol during Humulin R treatment. This is because drinking alcohol may affect how well Humulin R manages your blood sugar.
If you have concerns about avoiding or limiting alcohol during Humulin R treatment, talk with your doctor before starting treatment.
Here’s a closer look at certain drug interactions of Humulin R.
Fluoxetine
Fluoxetine (Prozac) is prescribed for certain mental health conditions, such as depression.
Humulin R may cause low blood sugar as a side effect. Taking fluoxetine during Humulin R treatment may further increase this risk. This could cause your blood sugar to fall below the typical range.
Having low blood sugar may cause symptoms such as headache, dizziness, sweating, and shaking. Severely low blood sugar may cause a person to lose consciousness and is a medical emergency.
Steps you or your doctor may take
If your doctor prescribes Humulin R with fluoxetine, they may prescribe a lower Humulin R dosage than usual. Doing so will help reduce your risk of low blood sugar when you take these medications together.
Your doctor will recommend what to do if you have symptoms of low blood sugar. They’ll likely advise you to raise your blood sugar by eating at least 15 grams (g) of carbohydrates. Carbohydrate sources include glucose tablets, hard candies, fruit juice, and non-diet sodas.
If your symptoms seem severe or life threatening, you or a bystander should call 911 or a local emergency number right away.
To learn more about Humulin R and fluoxetine, talk with your doctor or pharmacist.
Certain antipsychotics
Antipsychotics are prescribed for certain mental health conditions, such as schizophrenia.
Humulin R is used to help manage blood sugar levels in people with type 1 or type 2 diabetes. Certain antipsychotics may increase blood sugar levels. Taking these drugs together may affect how well Humulin R manages your blood sugar.
Here are some antipsychotics that may interact with Humulin R:
- aripiprazole (Abilify, Aristada, others)
- brexpiprazole (Rexulti)
- olanzapine (Zyprexa)
Steps you or your doctor may take
If your doctor prescribes Humulin R with certain antipsychotics, they may advise you to check your blood sugar levels more often than is typical. They’ll use your blood sugar levels to decide whether your Humulin R dosage should be adjusted.
To learn more about Humulin R and antipsychotics, talk with your doctor or pharmacist.
Corticosteroids
Corticosteroids are prescribed to help manage inflammation. They’re used to treat many conditions, such as allergies, asthma, and hives.
Corticosteroids may temporarily increase blood sugar levels during treatment. Humulin R is used to help manage blood sugar levels. Taking these drugs together may affect how well Humulin R manages your blood sugar.
Here are some corticosteroids that may interact with Humulin R:
- dexamethasone (Hemady)
- methylprednisolone (Medrol)
- prednisone
Steps you or your doctor may take
If your doctor prescribes a corticosteroid with Humulin R, they may have you check your blood sugar levels more often than is typical. If needed, they’ll temporarily adjust your Humulin R dosage during your corticosteroid treatment.
To learn more about Humulin R and corticosteroids, talk with your doctor or pharmacist.
Humulin R may have other interactions, such as with supplements, foods, vaccines, or lab tests.
Here are some potential interactions with Humulin R. Keep in mind that the following information does not include all possible Humulin R interactions. For more information, you can review the prescribing information for Humulin R U-100 and Humulin R U-500.
Humulin R interactions with supplements
Humulin R may interact with the following supplements:
These supplements are sometimes used to help manage blood sugar levels. (Humulin R is also prescribed for this use.) Administering Humulin R with green tea, garlic, or DHEA supplements may lower your blood sugar below the typical range.
Before you start treatment with Humulin R, tell your doctor and pharmacist about any supplements, herbs, and vitamins you take. By sharing this information with them, you may help prevent possible interactions.
If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.
Humulin R and herbs
There are no specific reports of herbs interacting with Humulin R. However, that doesn’t mean herbal interactions won’t occur or be recognized in the future. Because of this, it’s important to check with your doctor or pharmacist before taking any of these products during Humulin R treatment.
Humulin R interactions with vitamins and minerals
Humulin R may interact with niacin (vitamin B3). This vitamin may raise your blood sugar level, which could make Humulin R less effective in managing your blood sugar.
Humulin R may also interact with chromium. This is a mineral that some people take to help manage their blood sugar levels. Administering Humulin with chromium may lower your blood sugar below the typical range.
If you take products that contain niacin or chromium, your doctor may adjust your Humulin R dosage.
Before you start treatment with Humulin R, tell your doctor and pharmacist about any vitamins you take. They can advise you on whether Humulin R may interact with any of them.
Humulin R interactions with food
Consuming too much green tea during Humulin R treatment could lower your blood sugar below the typical range. For this reason, your doctor may advise you to limit how much green tea you consume during Humulin R treatment.
Although Humulin R may interact with garlic supplements, the amount of garlic in foods and seasonings is typically much less than what’s in a garlic supplement.
If you’d like to learn more about eating certain foods while using Humulin R, talk with your doctor.
Humulin R interactions with vaccines
There aren’t any known interactions between Humulin R and vaccines. Talk with your doctor or pharmacist to check whether you’re due for any vaccines.
Humulin R interactions with lab tests
Humulin R isn’t known to interact with lab tests. If you have concerns about interactions with Humulin R and lab tests, talk with your doctor.
HUMULIN R AND CANNABIS OR CBDCannabis (often called marijuana) and cannabis products, such as cannabidiol (CBD), have not been specifically reported to interact with Humulin R U-100 or Humulin R U-500. However, as with any drug or supplement, talk with your doctor before using cannabis in combination with Humulin R. The impact of cannabis may affect how well you stick to your Humulin R treatment plan.
Note: Cannabis is illegal at a federal level but is legal in many states to varying degrees.
Certain medical conditions and other factors may increase the risk of interactions with Humulin R. Before administering Humulin R, be sure to talk with your doctor about your health history. Humulin R may not be the right treatment option if you have certain medical conditions or other factors affecting your health.
Health conditions or factors that might interact with Humulin R include:
- Kidney or liver problems: If you have a kidney or liver problem, such as kidney failure or liver failure, talk with your doctor before starting Humulin R treatment. Having a kidney or liver problem may increase your risk of low blood sugar. Your doctor may prescribe a lower Humulin R dosage than is typical.
- Episode of low blood sugar: Doctors will advise you not to administer Humulin R during an episode of low blood sugar. For more information, see the “When to avoid Humulin R” section.
- Allergic reaction: If you’ve had an allergic reaction to Humulin R or any of its ingredients, your doctor will likely not prescribe Humulin R. Administering Humulin R could cause another allergic reaction. You can ask them about other treatments that may be better choices for you.
- Breastfeeding: It’s likely safe to use Humulin R while breastfeeding. Still, if you’re breastfeeding or planning to, talk with your doctor before starting Humulin R treatment.
- Pregnancy: It’s typically considered safe to administer Humulin R during pregnancy. However, if you’re pregnant or planning to become pregnant, it’s still important to talk with your doctor. They can advise you on whether Humulin R is the right treatment option.
You can take certain steps to help prevent interactions with Humulin R. Your doctor and pharmacist are key resources, so reaching out to them before starting treatment is a helpful first step. For example, it’s important that you plan to do the following:
- Let them know if you drink alcohol or use cannabis.
- Tell them about any other medications you take, as well as any supplements, herbs, and vitamins.
- Create a
medication listTrusted Source , which your doctor and pharmacist can help you fill out.
It’s also important to read the Humulin R label and other
If Humulin R doesn’t come with paperwork, you can ask your pharmacist to print a copy. If you need help reading or understanding this information, ask your doctor or pharmacist.
You can also help prevent interactions with Humulin R by using it exactly as your doctor prescribes.
Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
