Collagenase Clostridium histolyticum injection (Xiaflex) is used to treat Dupuytren's contracture (a painless thickening and tightening of tissue [cord] beneath the skin in the palm of the hand, which may make it difficult to straighten one or more fingers) when a cord of tissue can be felt upon examination. Collagenase Clostridium histolyticum injection (Xiaflex) is also used to treat Peyronie's disease (a thickening of tissue [plaque] inside the penis that causes the penis to curve). Collagenase Clostridium histolyticum injection (QWO) is also used to treat cellulite (fat deposit beneath the skin) in the buttocks of adult women. Collagenase Clostridium histolyticum injection is in a class of medications called enzymes. In people with Dupuytren's contracture, it works by helping to break down the cord of thickened tissue and allows the finger(s) to be straightened. In people with Peyronie's disease, it works by helping to break down the plaque of thickened tissue and allows the penis to be straightened. In women with cellulite, it works by releasing fibrous bands, redistributing fat cells, and stimulating the growth of new collagen.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Collagenase Clostridium histolyticum injection comes as a powder to be mixed with a liquid and injected by a doctor. If you are receiving collagenase Clostridium histolyticum injection (Xiaflex) to treat Dupuytren's contracture, your doctor will inject the medicine into a cord just under the skin in the affected hand. If you are receiving collagenase Clostridium histolyticum injection (Xiaflex) to treat Peyronie's disease, your doctor will inject the medicine into the plaque that is causing your penis to curve. If you are receiving collagenase Clostridium histolyticum (QWO) to treat cellulite, your doctor will inject it subcutaneously (just under the skin) into the buttock(s). Your doctor will choose the best place to inject the medication in order to treat your condition.

If you are receiving treatment for Dupuytren's contracture, do not bend or straighten the fingers of the injected hand or put pressure on the injected area after your injection. Keep the injected hand elevated until bedtime. You must return to your doctor's office on the day after your injection. Your doctor will check your hand, and possibly move and extend the finger to help break up the cord. Ask your doctor when you can expect to see improvement, and call your doctor if your condition does not improve during the expected time. Your doctor may need to give you additional injections if your condition does not improve. Do not perform strenuous activity with the injected hand until your doctor tells you that you can do so. Your doctor will probably tell you to wear a splint every night (at bedtime) for up to 4 months after the injection. Your doctor may also tell you to do finger exercises each day. Follow the directions of your doctor carefully and ask the doctor to explain any part you do not understand.

If you are receiving treatment for Peyronie's disease, your doctor will inject collagenase Clostridium histolyticum into your penis, followed by a second injection 1 to 3 days after the first injection. You must return to your doctor's office 1 to 3 days after your second injection. Your doctor will gently move and stretch your penis (penile modeling procedure) to help straighten your penis. Your doctor will also tell you to gently stretch and straighten your penis at home for 6 weeks afterward. Follow the directions of your doctor carefully and ask the doctor to explain any part you do not understand. Avoid sexual activity between the first and second injections of collagenase Clostridium histolyticum until your doctor tells you that you may resume sexual activity after each treatment cycle. Avoid situations that may cause you to strain your stomach (abdominal) muscles, such as straining during bowel movements, during your treatment. Your doctor may need to give you up to 3 additional treatment cycles depending on your response to collagenase Clostridium histolyticum injection.

If you are receiving treatment for cellulite, your doctor will inject collagenase Clostridium histolyticum (QWO) into each buttock (treatment area) with up to 12 injections in each treatment area. You may receive injections into two treatment areas during each visit. Your doctor will repeat treatments every 21 days for a total of 3 visits.

Before receiving collagenase Clostridium histolyticum injection,

• tell your doctor and pharmacist if you are allergic to collagenase Clostridium histolyticum injection, collagenase ointment (Santyl), any other medications, or any of the ingredients in collagenase Clostridium histolyticum injection. Ask your pharmacist or check the Medication Guide for a list of the ingredients.

• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.

• tell your doctor if you have an infection in the affected area. Your doctor will probably tell you not to receive collagenase Clostridium histolyticum injection. for the treatment of cellulitis.

• tell your doctor if you have or have ever had a bleeding condition that makes it difficult for you to form clots, including receiving anticoagulant medications (e.g., aspirin more than 150 mg a day, warfarin, enoxaparin, etc.) 7 days prior to receiving collagenase injection. Also, tell your doctor if you have previously received collagenase Clostridium histolyticum injection to treat another condition.

• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while receiving collagenase Clostridium histolyticum injection, call your doctor.

• you should know that collagenase Clostridium histolyticum injection may cause dizziness, lightheadedness, and fainting. This is more common if you have pain immediately after you receive your injection or within 1 to 2 days after the injection. If you feel dizzy or faint after you receive collagenase Clostridium histolyticum injection, you should lie down until your symptoms go away.

Unless your doctor tells you otherwise, continue your normal diet.

Collagenase Clostridium histolyticum injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away.

For people receiving collagenase Clostridium histolyticum (Xiaflex) for Dupuytren's contracture:

• redness, warmth, swelling, tenderness, bruising, or bleeding around the injected area
• itching of the treated hand
• pain in the treated hand
• painful and swollen glands in the elbow or underarm area

For men receiving collagenase Clostridium histolyticum (Xiaflex) for Peyronie's disease:

• tenderness around the injected area (along and above penis)
• blisters at the injection site
• lump at the injection site
• changes in color of the skin of penis
• itching of the penis or scrotum
• painful erection
• erection problems
• painful sexual activity
• headache

For women receiving collagenase Clostridium histolyticum (QWO) for cellulite:

• redness, warmth, swelling, hardness, skin color changes, or bruising around the injected area
• pain in the treated buttock

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

• hives
• rash
• difficulty breathing or swallowing
• hoarseness
• chest pain
• lower back pain moving to legs, feet, chest and arms
• muscle spasms
• swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
• fever, sore throat, chills, cough and other signs of infection
• numbness, tingling, or increased pain in your treated finger or hand (after your injection or after your follow-up visit)

When collagenase Clostridium histolyticum injection (Xiaflex) is used to treat to treat Dupuytren's contracture, it can cause injury to the hand that may require surgical treatment or can be permanent. Call your doctor right away if you have trouble bending your injected finger toward the wrist after the swelling goes away, or if you have problems using your treated hand after your follow-up visit. Talk to your doctor about the risks of receiving this medication.

Collagenase Clostridium histolyticum injection may cause other side effects. Call your doctor if you have any unusual problems while receiving this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep all appointments with your doctor.

Ask your doctor or pharmacist any questions you have about collagenase Clostridium histolyticum injection.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.