Phenol Injections

This resource from Children's Hospital of Philadelphia (CHOP) provides important information about phenol injections used to improve muscle tightness.

Important information:

Why does my child need phenol injections?

Phenol injections are usually recommended for children who have spastic or tight muscles that cause problems with function, development, and care. It can be used along with more conservative measures, such as physical and occupational therapy, or use of orthotics or other positioning devices. It can also be used along with oral medicines for treatment of muscle tightness or spasms. Other times, it is recommended on its own to treat tight muscles or spasms. Unlike oral medicines, it can target specific muscle groups and side effects sound with other antispastic medicines are less likely.

What is phenol?

Phenol is a type of alcohol that your healthcare provider may inject into your child's muscles to help control spasticity. Phenol works as a nerve block. Phenol is usually injected into large nerves causing spasticity of the muscles, such as the hamstrings, on the back of the thigh or the calf muscles. Your provider will use a low-intensity electrical stimulation machine (nerve stimulator) or ultrasound to choose the exact site for the injection in the muscle.

Who gets phenol injections?

Phenol has been used for patients who have:

• Spasticity from stroke, brain injury, and cerebral palsy

• A history of allergy to botulinum toxin, such as Botox ®

• Severe spasticity that requires multiple injections

It is often used with botulinum toxin injections because the amount of botulinum toxin is limited based on the patient's weight. The combination of botulinum toxin and phenol allows the most severe areas of spasticity to be treated.

What are the side effects of phenol?

• The most common side effects are pain and swelling during and after injections. Your child may have some mild pain and bruising at the injection site. Apply ice and be gentle with the site after the injection. The sites will be marked with adhesive bandages.

• Occasionally, muscle weakness may occur.

• Sensory changes may also happen after the injection. They will resolve on their own as nerves grow back.

• Serious side effects such as tremors or seizures are extremely rare but require immediate medical attention if they occur. If your child experiences any of these symptoms, call 911.

If you are interested in reading more about this medicine visit cpfamilynetwork.org.

Contact the Center for Rehabilitation at 215-590-7439, with any other questions or concerns.

Reviewed on March 1, 2023