Last reviewed 2026-04-22 · How we verify

Parafon Forte

University of California, San Francisco · FDA-approved active Small molecule

Parafon Forte is a Centrally-acting skeletal muscle relaxant Small molecule drug developed by University of California, San Francisco. It is currently FDA-approved for Acute musculoskeletal pain and muscle spasms. Also known as: Chlorzoxazone.

Parafon Forte is a muscle relaxant that works by depressing activity in the central nervous system to reduce muscle tension and pain.

Parafon Forte is a muscle relaxant that works by depressing activity in the central nervous system to reduce muscle tension and pain. Used for Acute musculoskeletal pain and muscle spasms, Adjunctive therapy for acute, painful musculoskeletal conditions.

At a glance

Generic name	Parafon Forte
Also known as	Chlorzoxazone
Sponsor	University of California, San Francisco
Drug class	Centrally-acting skeletal muscle relaxant
Modality	Small molecule
Therapeutic area	Musculoskeletal/Pain Management
Phase	FDA-approved

Mechanism of action

The active ingredient is chlorzoxazone, which acts as a centrally-acting skeletal muscle relaxant. It reduces muscle spasms and associated pain by depressing polysynaptic reflexes in the spinal cord and brainstem, rather than by direct action on skeletal muscle. It is typically used as an adjunct to rest and physical therapy for acute musculoskeletal conditions.

Approved indications

Acute musculoskeletal pain and muscle spasms

Common side effects

Dizziness
Drowsiness
Headache
Gastrointestinal upset
Hepatotoxicity (rare)

Key clinical trials

Placebo-Controlled Cross Over Trial of Chlorzoxazone Intake (PHASE4)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Source	Used for
ClinicalTrials.gov	Trial enrolment, design, endpoints, results

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

Parafon Forte CI brief — competitive landscape report
Parafon Forte updates RSS · CI watch RSS
University of California, San Francisco portfolio CI

Frequently asked questions about Parafon Forte

What is Parafon Forte?

Parafon Forte is a Centrally-acting skeletal muscle relaxant drug developed by University of California, San Francisco, indicated for Acute musculoskeletal pain and muscle spasms.

How does Parafon Forte work?

Parafon Forte is a muscle relaxant that works by depressing activity in the central nervous system to reduce muscle tension and pain.

What is Parafon Forte used for?

Parafon Forte is indicated for Acute musculoskeletal pain and muscle spasms.

Who makes Parafon Forte?

Parafon Forte is developed and marketed by University of California, San Francisco (see full University of California, San Francisco pipeline at /company/university-of-california-san-francisco).

Is Parafon Forte also known as anything else?

Parafon Forte is also known as Chlorzoxazone.

What drug class is Parafon Forte in?

Parafon Forte belongs to the Centrally-acting skeletal muscle relaxant class. See all Centrally-acting skeletal muscle relaxant drugs at /class/centrally-acting-skeletal-muscle-relaxant.

What development phase is Parafon Forte in?

Parafon Forte is FDA-approved (marketed).

What are the side effects of Parafon Forte?

Common side effects of Parafon Forte include Dizziness, Drowsiness, Headache, Gastrointestinal upset, Hepatotoxicity (rare).

Drug class: All Centrally-acting skeletal muscle relaxant drugs
Manufacturer: University of California, San Francisco — full pipeline
Therapeutic area: All drugs in Musculoskeletal/Pain Management
Indication: Drugs for Acute musculoskeletal pain and muscle spasms
Also known as: Chlorzoxazone

Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing