Heparin Dosages for Adults: Your GoodRx Guide

Advances in medicine are happening all the time. With them come new treatment options and, potentially, better health outcomes. But even with a treatment landscape that is now more abundant, there is often still a place for medications that have been around for decades. 

One such medication is called heparin. It was discovered by accident in 1916 and started being used as an anticoagulant (blood thinner) about a decade later. It was the first blood thinner to be discovered, but since then, many other blood thinners have been developed. Though there’s now a larger number of anticoagulants to choose from, your healthcare provider might decide it’s the best choice for you. You might receive heparin to prevent or treat blood clots while in the hospital, or to treat a rare condition that causes blood clots (disseminated intravascular coagulation).

If you’ve been prescribed heparin (or are receiving it in the hospital), you may be wondering what to expect. Let’s discuss some important considerations around heparin dosages and administration.

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What’s the typical heparin dosage for adults?

There isn’t one typical dosage for heparin. Heparin dosages are calculated based on your body weight and health status. The formulation you receive also makes a difference.

Heparin is available as an under-the-skin (subcutaneous) injection and an infusion given in your vein (intravenous, IV). Healthcare providers find it useful because it works quickly and is easily reversible. The IV infusion is preferred when you need heparin to work immediately, such as when you have an active clot. The under-the-skin injection takes about 1 to 2 hours to start working, so it’s typically used in less urgent situations.

The infusion can be given continuously or once every 4 to 6 hours. The injection is given every 8 to 12 hours. But a higher heparin dose (loading dose) is often given first when treating an active clot — this ensures that heparin reaches effective levels in your blood more quickly. 

After the loading and initial maintenance doses, future heparin doses are guided by the results of what your blood work says.

For example, a common IV heparin dose is 80 units per kg body weight as a loading dose. This is followed by a maintenance dose of 18 units per kg body weight per hour. Future doses may be higher or lower depending on your bloodwork results. Subcutaneous heparin doses follow a similar pattern.

Heparin at the hospital

Heparin dosages are complex and variable. If you’re in the hospital, your healthcare provider will be in charge of determining how much heparin you need. Most hospitals even have standardized protocols in place to guide heparin use.

These protocols recommend different heparin dosages in certain medical situations. For example: 

• Active blood clots in your arms, legs, or lungs

• Acute coronary syndromes, including a heart attack

• Stroke

• Atrial fibrillation

• Blood clot prevention during a hospital stay

At-home heparin use

In some cases, you may be asked to continue injecting heparin at home for a set period of time. This is done for ongoing blood clot prevention. A pharmacist, nurse, or physician should show you how to administer subcutaneous heparin before you’re discharged. This instruction will likely include how much heparin to inject at a time, how often you should administer it, and tips on injection technique.

One example of when this may happen is for blood clot prevention after a surgical procedure. You may be asked to administer 5,000 units of heparin under the skin every 8 to 12 hours for 7 days or until you’re able to move around again.

Want more information? Here’s a GoodRx Health guide on how to give yourself a shot.

Are there any dosage adjustments for medical conditions?

One of heparin’s benefits is that the dose doesn’t need to be adjusted for liver or kidney problems. But there are other situations in which your healthcare provider may want to adjust your dose.

If your body weight is higher than a certain reading, your provider may decide to limit heparin to a maximum dose. This is done to prevent you from getting too much heparin, which would otherwise increase your risk of bleeding. Your provider may also take into account your current bleeding risk to determine the best dose for you. Your age, other health conditions, and history of bleeding all play a role in this.

If you’re being treated for an active condition while in the hospital, the best way to ensure a safe dose is through blood monitoring. Your healthcare team will take care of this for you.

What happens if you miss a dose of heparin?

If you're receiving heparin in the hospital, it’s not likely you’ll miss a dose. Your care team will be giving it to you on a schedule. If you do happen to miss a dose, your healthcare team will adjust your dose based on blood monitoring.

If you’re administering the injections at home and you miss a dose, you should reach out to your healthcare team. They can assist you with starting a new or revised dose schedule. Don’t double up on the dose, either — that increases your risk for bleeding.

What should you do if you receive too much heparin?

If you’re receiving heparin in the hospital, your healthcare team will likely take a look at your blood tests and adjust your dose accordingly. If you received too much heparin and you’re actively bleeding, you’ll receive a reversal treatment called protamine. This medication attaches to heparin and neutralizes it in your bloodstream.

If you’re taking heparin outside of the hospital and you accidentally take too much heparin, you should immediately call your healthcare team for guidance. If you’re actively bleeding, have someone take you to the closest emergency room or call 911.

Good to know: Protamine has a boxed warning (the strongest FDA warning) for severe low blood pressure and decreased heart and lung function. Because of this risk, you can only receive protamine in the hospital.

How to save on heparin

Depending on what you’re receiving it for, heparin may be covered under your prescription or medical insurance benefit. But if heparin isn’t covered or your copay is too high, GoodRx can help you find ways to save.

• Save with GoodRx. GoodRx can help you save over 90% off the average retail price of heparin. Generic heparin’s price is as low as $34.13 for 60 vials with a free GoodRx discount.

• Save with patient assistance programs. If you’re uninsured or underinsured, you may qualify for a patient assistance program. These include foundations that may be able to provide you a grant depending on your income. If you’re receiving heparin in the hospital, the health system might also have an in-house financial assistance program.

Why trust our experts?

Written by:

Rachel Feaster, PharmD, BCOP, BCPS

Rachel Feaster has over 10 years of professional experience in ambulatory, inpatient, pharmacogenomics, and oncology care. She is board certified in oncology and pharmacotherapy.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

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