Your doctor has ordered heparin, a medication to thin your blood, to help prevent blood clots from forming in your body. Heparin may also be given to prevent blood clots that have already formed from getting any bigger. Heparin will be injected into a vein (intravenously) or under the skin (subcutaneously). Your doctor will decide the best dosing schedule for you.

You may receive heparin intravenously for 1 or 2 weeks, while subcutaneous injections may continue for up to 6 weeks or 6 months. This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Your health care provider (doctor, nurse, or pharmacist) may measure the effectiveness and side effects of your treatment using laboratory tests and physical examinations. It is important to keep all appointments with your doctor and the laboratory. The length of treatment depends on how you respond to the medication.

Before administering heparin,

• tell your doctor and pharmacist if you are allergic to heparin, pork products, or any other drugs.
• tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially aspirin, ibuprofen (Motrin), medications for headaches or pain, naproxen (Anaprox, Aleve), and vitamins.
• tell your doctor if you have or have ever had kidney disease or diabetes.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking heparin, call your doctor.

Before administering heparin,

• tell your doctor and pharmacist if you are allergic to heparin, pork products, or any other drugs.
• tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially aspirin, ibuprofen (Motrin), medications for headaches or pain, naproxen (Anaprox, Aleve), and vitamins.
• tell your doctor if you have or have ever had kidney disease or diabetes.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking heparin, call your doctor.