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Qwo Side Effects

Generic name: collagenase clostridium histolyticum

Medically reviewed by Last updated on Sep 6, 2022.

Note: This document contains side effect information about collagenase clostridium histolyticum. Some dosage forms listed on this page may not apply to the brand name Qwo.

Applies to collagenase clostridium histolyticum: injection powder for solution.


Injection route (Powder for Solution)

Warning: Corporal rupture (penile fracture) or other serious penile injury in the treatment of Peyronie's diseaseCorporal rupture (penile fracture) was reported as an adverse reaction in 5 of 1044 (0.5%) collagenase clostridium histolyticum-treated patients in clinical studies. In other collagenase clostridium histolyticum-treated patients (9 of 1044; 0.9%), a combination of penile ecchymoses or hematoma, sudden penile detumescence, and/or penile "popping" sound or sensation was reported, in these cases, a diagnosis of corporal rupture cannot be excluded. Severe penile hematoma was also reported as an adverse reaction in 39 of 1044 (3.7%) collagenase clostridium histolyticum-treated patients.Signs or symptoms that may reflect serious penile injury should be promptly evaluated to assess for corporal rupture or severe penile hematoma which may require surgical intervention.Because of the risks of corporal rupture or other serious penile injury, collagenase clostridium histolyticum is available for the treatment of Peyronie's disease only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the collagenase clostridium histolyticum REMS program.

Serious side effects of Qwo

Along with its needed effects, collagenase clostridium histolyticum (the active ingredient contained in Qwo) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking collagenase clostridium histolyticum:

More common—Dupuytren's contracture

  • Bruising or bleeding at the injection site
  • swelling of the hands
  • tearing of the skin

More common—Peyronie's disease

  • Itching, pain, redness, swelling, or bruise of the penis
  • popping sound or sensation in an erect penis

Less common—Peyronie's disease

  • Decreased interest in sexual intercourse
  • inability to have or keep an erection
  • loss in sexual ability, desire, drive, or performance
  • painful sexual intercourse

Incidence not known—Dupuytren's contracture

  • Bone pain
  • dizziness
  • fainting
  • lower back or side pain
  • painful, swollen joints

Incidence not known—Peyronie's disease

  • Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • chest pain or tightness
  • difficult or labored breathing
  • dizziness
  • fainting
  • lower back pain, possibly radiating to the legs, feet, arms, or chest
  • muscle spasms

Other side effects of Qwo

Some side effects of collagenase clostridium histolyticum may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common—Dupuytren's contracture

  • Blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, lumps, numbness, rash, scarring, stinging, tingling, or ulceration at the injection site
  • bruise
  • flushing, redness of the skin or unusually warm skin at the injection site
  • itching, pain, swelling, or tenderness at the injection site
  • swollen, painful, or tender lymph glands in the neck or armpit

For Healthcare Professionals

Applies to collagenase clostridium histolyticum: injectable powder for injection.


Very common (10% or more): Pain in extremity (35%), arthralgia (11%)

Common (1% to 10%): Shoulder pain

Uncommon (0.1% to 1%): Axillary mass, chest wall pain, groin pain, joint crepitation, joint stiffness, limb discomfort, muscle spasms, muscular weakness, musculoskeletal stiffness, neck pain, tendon rupture[Ref]


Very common (10% or more): Injection site hemorrhage (38%), injection site reaction (erythema, inflammation, irritation, pain, warmth) (35%), injection site swelling and edema (24%), pruritus (15%), blood blister (13%)

Common (1% to 10%): Ecchymosis, hyperhidrosis, rash, skin laceration

Uncommon (0.1% to 1%): Eczema, swelling face, pain of skin, skin exfoliation, skin lesion, scab, skin discoloration, skin tightness[Ref]


Very common (10% or more): Peripheral edema (most cases were swelling of the injected hand) (73%)

Frequency not reported: Vasovagal syncope (after finger extension procedures)[Ref]


Very common (10% or more): Contusion (any body system) and ecchymosis (70%), tenderness (24%)

Common (1% to 10%): Axillary pain

Uncommon (0.1% to 1%): Breast tenderness, hypertrophy breast[Ref]


Common (1% to 10%): Lymphadenopathy, lymph node pain

Uncommon (0.1% to 1%): Thrombocytopenia[Ref]


Common (1% to 10%): Nausea

Uncommon (0.1% to 1%): Diarrhea, vomiting, abdominal pain upper[Ref]


Patients with Peyronie's disease:

Very common (10% or more): Penile hematoma (65.5%), penile swelling (55%), penile pain (45.4%), penile ecchymoses (14.5%), a popping noise or popping sensation in the penis, sometimes described as "snapping" or "cracking", and sometimes accompanied by detumescence, hematoma, and/or pain (13.2%)

Common (1% to 10%): blood blister (4.5%), penile blister (3.3%), genital pruritus (3.1%), painful erection (2.9%), erectile dysfunction (1.8%), procedural pain (1.6%), injection site vesicles (1.3%), localized edema (1.3%), dyspareunia (1.1%), injection site pruritus (1.1%), nodule (1.1%), suprapubic pain (1.1%)

Uncommon (0.1% to 1%): Corporal rupture (penile fracture) (0.5%)[Ref]


Very common (10% or more): Lymphadenopathy (13%)

Common (1% to 10%): Lymph node pain

Uncommon (0.1% to 1%): Thrombocytopenia[Ref]


Uncommon (0.1% to 1%): Hypersensitivity[Ref]


Uncommon (0.1% to 1%): Injection site cellulitis, lymphangitis[Ref]

Nervous system

Common (1% to 10%): Burning sensation, dizziness, headache, hypoesthesia, paresthesia

Uncommon (0.1% to 1%): Disorientation, agitation, insomnia, irritability,



Uncommon (0.1% to 1%): Eyelid edema[Ref]


Uncommon (0.1% to 1%): Dyspnea, hyperventilation[Ref]

Frequently asked questions

More about Qwo (collagenase clostridium histolyticum)

Patient resources

Other brands


Professional resources

Related treatment guides


1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

2. Pharmaceutical Society of Australia "APPGuide online. Australian prescription products guide online." (2006):

3. "Product Information. Xiaflex (collagenase clostridium histolyticum)." Auxilium Pharmaceuticals Inc (2010):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.