Reviewed on 9/1/2021

What Is Arbaclofen Used For and How Does it Work?

Arbaclofen is an investigational drug used to decrease spasticity related to multiple sclerosis (MS). Arbaclofen also is being studied to improve social function and behavior in patients with fragile X syndrome (FXS). Arbaclofen is also being studied in autism spectrum disorder (ASD).

  • Arbaclofen is available under the following different brand names: N/A

What Are Dosages of Arbaclofen?

Dosages of Arbaclofen:

Adult and Pediatric Dosage Forms and Strengths


  • 5 mg
  • 10 mg
  • 20 mg
Dosage Considerations – Should be Given as Follows:

Multiple Sclerosis (MS)

  • Arbaclofen extended-release (ER), 20 mg twice daily

Fragile X Syndrome (FXS)

  • Children aged 6-11 years: 10 mg twice daily
  • Patients aged 12 to 40 years: 10 mg three times daily

Autism Spectrum Disorder (ASD)

  • 5 mg twice daily, and could be increased every 7 days to 10 mg twice daily, 10 mg 3 times daily, and 15 mg 3 times daily.
  • Dosage was capped at 10 mg 3 times daily for patients 12 years and younger

What Are Side Effects Associated with Using Arbaclofen?

Common side effects of Arbaclofen include:

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Arbaclofen?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • There is no information available on severe, serious, moderate, or mild interactions of arbaclofen with other drugs.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

What Are Warnings and Precautions for Arbaclofen?


This medication contains arbaclofen. Do not take Kaopectate Maximum Strength, Diasorb, or K-Pek if you are allergic to arbaclofen or any ingredients contained in this drug.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


  • No information available

Effects of Drug Abuse

  • No information is available.

Short-Term Effects

  • See "What Are Side Effects Associated with Using Arbaclofen?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Arbaclofen?"


  • No information available

Pregnancy and Lactation

There is no information available on the use of arbaclofen during pregnancy or while breastfeeding. Arbaclofen is an investigational drug.


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