Dosage for Herceptin: What You Need to Know

If you have certain types of breast cancer or stomach cancer, your doctor might suggest Herceptin as a treatment option.

Herceptin is a prescription medication used in adults to treat:

• breast cancer, when used together with other medications
• metastatic breast cancer (meaning breast cancer that’s spread to other parts of your body)
• stomach or esophageal cancer that has spread to other areas of the body

Specifically, this medication should only be used to treat cancers that are human epidermal growth factor receptor 2 (HER2)-positive. Your doctor will test your cancer prior to treatment to see if Herceptin may be a good option for you.

Herceptin comes as a powder that’s mixed into a liquid solution. It’s given as an intravenous (IV) infusion (an injection into your vein given over time).

Herceptin belongs to a group of drugs called HER2/neu receptor antagonists. The active ingredient in Herceptin is trastuzumab.

This article describes the dosages of Herceptin, as well as its strength and how it’s given. To learn more about Herceptin, see this in-depth article.

Note: This article covers Herceptin’s typical dosages, which are provided by the drug’s manufacturer. But your doctor will prescribe the Herceptin dosage that’s right for you.

Before you start treatment with Herceptin, your doctor will determine how often Herceptin is given and the best dose for you. Discuss your specific dosing guidelines with your doctor before starting Herceptin.

What is Herceptin’s form?

Herceptin is available as a powder that comes in a single-dose vial. With a single-dose vial, each vial contains only one dose of medication. The powder is mixed into a liquid solution to be injected into a vein.

What strength does Herceptin come in?

Herceptin vials contain 150 milligrams (mg) of medication.

What are the typical dosages of Herceptin?

Your doctor will likely recommend that you receive a higher dose of Herceptin for your first dose. This is called a loading dose. It helps the medication start working more quickly. Your doctor will then recommend a lower dose of medication. They’ll ultimately prescribe the smallest dosage that provides the desired effect.

The information below describes dosages that are commonly used or recommended. Your doctor will determine the best dosage to fit your needs.

Dosage for HER2-positive breast cancer

Herceptin can be used to treat HER2-positive breast cancer. The dosing for Herceptin is based on your body weight.

Herceptin along with other treatments

Herceptin can be used together with other medications to treat HER2-positive breast cancer. These medications include:

• paclitaxel
• docetaxel
• docetaxel and carboplatin together

When prescribing Herceptin with these other medications, your doctor will likely recommend a starting dose of 4 milligrams per kilogram (mg/kg) of body weight. This infusion will be given into a vein over the course of 90 minutes.

After your first infusion, you’ll only need a dose of 2 mg/kg over 30 minutes. You’ll likely get this dose once weekly for the first 12 or 18 weeks, depending on your treatment plan. You’ll then continue getting Herceptin at a dosage of 6 mg/kg once every 3 weeks. (This is called a maintenance dose, meaning it’s the dose you’ll likely receive for the rest of your treatment.) This infusion can be given over a period of 30 to 90 minutes.

Below is a table showing the dosing of Herceptin if you’re taking it with other treatments:

For example, if you weigh 80 kg (about 176 lbs.), your starting dose will be one dose of 320 mg. Then, your dose will decrease to 160 mg once weekly for 12 weeks or 18 weeks, depending on your treatment plan. After that, you’ll only need a dose of 480 mg once every 3 weeks.

Herceptin after other treatments

In some cases, your doctor may recommend a different chemotherapy regimen, and then start you on Herceptin within 3 weeks of completing it. In this case, you’ll likely start with a dose of 9 mg/kg injected over 90 minutes. After that, you’ll only need one dose of 6 mg/kg once every 3 weeks. This dose can be given over 30 to 90 minutes.

The table below summarizes the dosage of Herceptin you’ll receive if using it after completing a different chemotherapy regimen:

For example, if you weigh 80 kg (about 176 lbs.), your starting dose will be 720 mg. After that, you’ll only need a dose of 480 mg once every 3 weeks.

Your doctor will likely recommend treatment for 1 year if Herceptin is working well for you. After 1 year, your doctor may recommend continuing on a different treatment plan.

Dosage for HER2-positive breast cancer that’s metastatic

The recommended starting dose of Herceptin for metastatic breast cancer is 4 mg/kg, which should be given over 90 minutes. (“Metastatic” means the cancer has spread to other areas of your body.) After your first dose, your doctor will likely recommend a dosage of 2 mg/kg once each week. You can use Herceptin for metastatic breast cancer until your cancer worsens or you have serious side effects.

To summarize, the dosing of Herceptin for metastatic breast cancer is as follows:

For example, if you weigh 80 kg (about 176 lbs.), your starting dose of Herceptin would be 320 mg. After that, you’d only need one dose of 160 mg each week.

Dosage for HER2-positive gastric cancer or gastroesophageal junction adenocarcinoma that’s metastatic

If you’re taking Herceptin to treat HER2-positive stomach or esophageal cancer, your starting dose would be 8 mg/kg. This dose will be given over 90 minutes. After your first dose, you’ll receive one dose of 6 mg/kg given over 30 to 90 minutes. You’ll only need this dose once every 3 weeks. You can continue taking Herceptin until your cancer gets worse or you have serious side effects.

To summarize, the dosing of Herceptin for stomach or esophageal cancer is as follows:

For example, if you weigh 80 kg (about 176 lbs.), your starting dose would be 640 mg. After that, you’d only need one dose of 480 mg of Herceptin every 3 weeks.

Is Herceptin used long term?

It depends on your treatment plan.

For metastatic breast cancer or stomach or esophageal cancer, your doctor will likely suggest you use Herceptin until your cancer gets worse.

If you’re taking Herceptin with other medications to treat breast cancer, you’ll likely not use it for more than 1 year.

Talk with your doctor about the best treatment plan for you.

Dosage adjustments

In some cases, your doctor may adjust your dosage of Herceptin.

Since this drug’s dosing is based on body weight, your dosage may change if you gain or lose weight. Your dosage may also change if you use Herceptin with other medications.

If you have questions about your dosage of Herceptin, talk with your doctor.

I was receiving Herceptin once a week. Why is my dosage schedule changing to one dose every 3 weeks?

If you’re taking Herceptin with other medications to treat breast cancer, you’ll start with a loading dose. (See the answer to the question just below for an explanation of “loading dose.”) After your loading dose, you’ll get one dose of Herceptin each week.

• If you’re taking Herceptin with paclitaxel or docetaxel, you’ll get one weekly dose of Herceptin for 12 weeks.
• If you’re taking Herceptin with docetaxel and carboplatin, you’ll get one weekly dose of Herceptin for 18 weeks.

After either 12 weeks or 18 weeks (depending on your treatment plan), you’ll complete treatment with the additional medication(s). Once this combination treatment is finished, your dosing schedule of Herceptin will change from once weekly to once every 3 weeks.

But even though you’re getting infusions less often, the actual dose of medication doesn’t change. When you’re getting a dose of Herceptin once weekly, your dose is 2 mg/kg. But when receiving your dose once every 3 weeks, your dose is 6 mg/kg.

If you have questions about your dosing schedule, talk with your doctor or pharmacist.

What is a loading dose, and does Herceptin treatment require one?

A loading dose is a larger dose at the beginning of treatment. Loading doses are important because they help the medication start working more quickly in your body. After your loading dose, your doctor will likely recommend a lower dose of medication to continue your treatment.

Your doctor will likely recommend a loading dose of Herceptin when you first start treatment. After your first dose, they’ll reduce the dose while you continue treatment.

How many doses of Herceptin will I need for breast cancer treatment?

It depends on your specific cancer and treatment plan. If you’re using Herceptin with other medications to treat breast cancer, it’s unlikely you’ll receive it for more than one year.

If you’re receiving Herceptin to treat the following conditions, your doctor may recommend you use it until your cancer gets worse:

• metastatic breast cancer
• stomach cancer
• esophageal cancer

Talk with your doctor about your specific treatment plan. They’ll be able to recommend a dosing schedule to treat your cancer.

How is my Herceptin dose calculated?

Your dose of Herceptin is based on the type of cancer you have and your body weight.

For example, if you’re taking Herceptin for metastatic breast cancer, the recommended starting dosage is 4 mg/kg. So, if you weigh 80 kg (about 176 lbs.), your starting dose would be 320 mg. After your first dose, your doctor will likely recommend 2 mg/kg once per week until your cancer gets worse. So if you weigh 80 kg, your dose would be 160 mg per week.

Your doctor will create a treatment plan and dose calculation for you. Talk with them or a pharmacist if you have specific questions about how your Herceptin dose is calculated.

The dosage of Herceptin you’re prescribed may depend on several factors. These include:

• the type and severity of the condition you’re using it to treat
• your body weight
• other medications you’re taking (see “Dosage adjustments” under “What is Herceptin’s dosage?”)

You’ll receive your dose of Herceptin in your doctor’s office or in the hospital. A healthcare professional will mix your dose of Herceptin into a liquid solution. This is then given to you as an intravenous (IV) infusion (an injection into your vein given over time). Your infusion of Herceptin may take between 30 and 90 minutes.

If you miss your Herceptin dose and it’s been 1 week or less, your doctor will recommend you get it right away. Then you’ll continue with your regular dosing schedule.

If you miss your dose by more than 1 week, you’ll need to get another loading dose of Herceptin. (This is the higher dosage you get at the start of your treatment.) Then you can continue with your scheduled maintenance dosing.

If you need help remembering your appointment to get your dose of Herceptin, try using a medication reminder. This can include marking a calendar, setting an alarm or downloading a reminder app on your phone. Be sure to contact your doctor right away to reschedule a missed appointment.

The sections above describe the typical dosages provided by the drug’s manufacturer. If your doctor recommends Herceptin for you, they’ll prescribe the dosage that’s right for you. Talk with them if you have questions or concerns about your current dosage.

Here are some examples of questions you may want to ask your doctor:

• Does my dose of Herceptin need to be increased or decreased if I’m taking other medications with it?
• Do I need a different dosage of Herceptin based on my other medical conditions?
• If Herceptin isn’t working for me, can my dose be increased?

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Disclaimer: Healthline 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.