“Boy, do I have joint pain,” wrote one MyBCTeam member. “Every joint in my body aches.” A common side effect of many breast cancer treatments, joint pain can decrease your quality of life and make you feel worse during treatment. Some members have recommended Claritin as a remedy for joint pain from breast cancer treatment. Claritin is one of many brand-name formulations of loratadine, an antihistamine medication commonly used to treat allergies.

While it sounds strange that an allergy medication might help with joint pain from breast cancer therapy, there’s some evidence it may work. This article will cover everything you need to know about joint pain, loratadine, and what’s known about its safety and effectiveness as a joint pain remedy.

Joint Pain During Breast Cancer Treatment

Some breast cancer treatments can cause pain in any joint, including your hands, shoulders, back, hips, or knees.

Apart from joint pain, you may notice joint symptoms such as:

• Stiffness in the morning after you wake up
• Joint tenderness (feeling painful to the touch)
• Joint swelling or discoloration
• Warm feeling around the joint

Joint pain can start anytime after you start breast cancer treatment, but for some medications, it most commonly starts in the first two months of treatment and peaks at the six-month mark. For some people, joint pain can improve after a few months.

What Causes Joint Pain During Breast Cancer Treatment?

Several breast cancer treatments can cause joint pain as a side effect, including hormone therapy, chemotherapy, and targeted therapy.

Hormone Therapy

Several hormonal therapies used to treat breast cancer are known to cause joint pain, such as:

• Aromatase inhibitors, including letrozole (Femara), anastrozole (Arimidex), and exemestane (Aromasin)
• Fulvestrant (Faslodex)
• Tamoxifen (Soltamox)

In one study, almost half of people treated with anastrozole experienced joint pain ranging from mild to moderate pain to severe pain. Some people are more likely to experience joint pain while taking an aromatase inhibitor. Risk factors that increase the risk of joint pain include:

• Being younger in age during treatment
• Having taken a taxane chemotherapy
• Having taken a white blood cell (WBC)-stimulating drug
• Having another medical condition such as arthritis or fibromyalgia

Other Breast Cancer Treatments

Some chemotherapy drugs — especially taxane chemotherapy drugs such as paclitaxel (Abraxane) and targeted therapies like trastuzumab (Herceptin) — can cause joint pain.

Drugs that are given to prevent infection in people with low white blood cells can also cause bone and joint pain. These drugs are called granulocyte colony-stimulating factors (G-CSFs) and include filgrastim (Neupogen) and pegfilgrastim (Neulasta) — as well as drugs formulated from biosimilars of filgrastim and pegfilgrastim.

What Is Claritin?

Claritin is one brand name of the generic drug loratadine, an antihistamine medication commonly used to treat allergies. Other brands include Agistam, Alavert, Dimetapp, and Wal-itin. Formulations of loratadine are available over the counter, without a prescription, as liquids, tablets, capsules, and chewable tablets.

Loratadine works by blocking a chemical called histamine. Histamine is a signaling chemical primarily stored in your white blood cells. Histamine plays a role in regulating your inflammatory response. When your WBCs release histamine, it can cause an allergic reaction, pain, and widening of your blood vessels.

Loratadine is a relatively safe medication, but like all medications, it can cause side effects. Possible side effects of loratadine include:

• Headaches
• Dizziness
• Upset stomach
• Dry mouth

Can Claritin Help Joint Pain?

Several MyBCteam members have shared that they’ve taken loratadine for bone and joint pain caused by chemotherapy, pegfilgrastim, anastrozole, and letrozole. “I took it with my AC chemo to avoid bone pain, and it worked, don’t know why. I’m taking it with letrozole too, and it’s helping,” shared one member. Another member agreed, saying, “Same here. Don’t know how it worked, but it did!”

Researchers also aren’t exactly sure why loratadine might decrease joint pain, but they think that histamine may be involved with bone and joint pain caused by breast cancer treatments. Taking loratadine can block histamine from activating pain receptors.

While there aren’t any clinical trials studying loratadine for joint pain caused by anastrozole or letrozole, a few small clinical trials have studied how the drug affects bone pain in people taking pegfilgrastim.

In one clinical trial, participants used either naproxen (Naprosyn), loratadine, or no treatment for bone pain caused by pegfilgrastim. Researchers didn’t find a difference in the amount of bone pain experienced by people taking naproxen versus those taking loratadine. However, participants taking loratadine had fewer treatment-related side effects than those taking naproxen.

Another small study found that loratadine was associated with reduced pain in people taking G-CSFs.

Taking Claritin for Joint Pain

Talk to your cancer care team about whether taking loratadine is right for you. Loratidine isn’t known to cause interactions with many other medications, but there are a few, and your doctor can help make sure it’s safe.

If your doctor recommends that you take loratadine, follow their instructions exactly. Loratadine is usually taken at the same time each day with or without food. During clinical trials, participants took loratadine for a week starting the day of their pegfilgrastim injection.

If you go to the pharmacy to buy loratadine, you may find several different kinds. You can buy the brand or the generic, but make sure that loratadine is the only active ingredient. Unless your doctor tells you to, you shouldn’t take Claritin-D, which also has a decongestant.

Other Ways To Manage Joint Pain

If you experience joint pain or any other type of pain during breast cancer treatment, talk to your cancer care team about ways to manage it.

Apart from loratadine, some other ways to manage joint pain caused by breast cancer treatment include:

• Taking pain medications such as acetaminophen (Tylenol) or ibuprofen (Motrin, Advil)
• Exercising regularly
• Maintaining a healthy weight
• Getting massage therapy
• Practicing medication
• Undergoing acupuncture

Talk With Others Who Understand

MyBCTeam is the social network for people with breast cancer and their loved ones. On MyBCTeam, more than 63,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Have you taken Claritin to help with joint pain during breast cancer treatment? Share your experiences in the comments below, or start a conversation by posting on your Activities page.