Hylan G-F 20 belongs to the group of medications known as synovial fluid replacements. It is used to relieve the pain caused by osteoarthritis (a condition causing joint "wear and tear") in the knee joint, when other pain relievers have not adequately controlled the pain. It works by mimicking the body's own synovial fluid (a fluid that lubricates and cushions the joints). Relief from pain can last up to 6 months.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are being given this medication, speak to your doctor. Do not stop receiving this medication without consulting your doctor.

The usual recommended dose is a single injection into the knee joint. Your doctor or a trained health care professional will give you the injection, usually at a clinic or hospital setting.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are receiving the medication without consulting your doctor.

It is important to receive this medication exactly as prescribed by your doctor. If you miss an appointment for a dose of the injection, contact your doctor as soon as possible.

This medication is stored at room temperature and should not be allowed to freeze. It should be kept out of the reach of children.

Each mL of sterile, nonpyrogenic, elastoviscous fluid contains hylan 8 mg. Nonmedicinal ingredients: disodium hydrogen phosphate, sodium chloride, sodium dihydrogen phosphate hydrate, and water for injection.

Hylan G-F 20 should not be used by anyone who:

• is allergic to hylan G-F 20 or to any of the ingredients of the medication
• has a skin disease or infection near the planned injection area
• has an infected or severely swollen joint

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• knee stiffness
• mild pain, redness, heat, or swelling around the area of injection
• muscle aches

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• burning, prickling, or tingling sensations in the hands or feet
• continued pain, swelling, redness of the knee joint with or without a fever
• dizziness
• fever or chills
• flushing or swelling of the face
• headache
• muscle cramps
• nausea
• swelling of the hands, feet, or ankles
• tiredness

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of an allergic reaction (e.g., hives; difficulty breathing; swelling of the face, tongue, or throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Activity level: For a few days after receiving the injection, avoid strenuous activities such as jogging, tennis, heavy lifting, or standing for a long time. Consult your doctor before restarting these activities.

Allergies: This medication is prepared from chicken combs. People who are allergic to products from birds, such as feathers, eggs, and poultry may develop an allergic reaction to hylan G-F 20. People with allergies to products from birds should inform their doctor of this before receiving this medication and discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Circulation: People who have circulation problems of the legs or lymph ducts should use hylan G-F 20 cautiously. Inform your doctor if you have circulatory problems before receiving this medication. Discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks, as the safety and effectiveness of receiving this medication during pregnancy have not been established. If you become pregnant while receiving this medication, contact your doctor immediately.

Breast-feeding: It is not known if hylan G-F 20 passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children under 18 years of age.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. In many cases, interactions are intended or are managed by close monitoring. Speak to your doctor about how any drug interactions are being managed or should be managed.