Chlorzoxazone

Muscle relaxant
PRESCRIPTION ONLY IN INDIA

Chlorzoxazone is a muscle relaxant found in 2 medicines sold in India, such as Hifenac-MR, Myospaz Forte. Below: what it is for, how it works, how to take it, side effects, interactions and pregnancy advice.

What it is used for

Eases muscle spasm in back pain and sprains.

How it works

A muscle relaxant usually combined with paracetamol and an NSAID for muscle spasm.

How to take it

As directed, usually three times a day after food for a few days.

Common side effects

  • Drowsiness
  • Dizziness
  • Orange or red urine (harmless)

Get medical help straight away if

  • Yellow skin or dark urine
  • Severe rash

Be careful

Can cause drowsiness; rarely affects the liver.

Other medicines and interactions

More drowsiness with alcohol; liver risk with other liver-affecting medicines.

Pregnancy and breastfeeding

Not recommended in pregnancy or while breastfeeding.

Combination medicines that contain Chlorzoxazone (2)

Hifenac-MRMyospaz Forte

Common questions

What is Chlorzoxazone used for?

Eases muscle spasm in back pain and sprains.

How does Chlorzoxazone work?

A muscle relaxant usually combined with paracetamol and an NSAID for muscle spasm.

How should I take Chlorzoxazone?

As directed, usually three times a day after food for a few days.

What are the side effects of Chlorzoxazone?

Common: Drowsiness, dizziness, orange or red urine (harmless). Get help straight away for: Yellow skin or dark urine, severe rash.

Does Chlorzoxazone interact with other medicines?

More drowsiness with alcohol; liver risk with other liver-affecting medicines.

Is Chlorzoxazone safe in pregnancy and breastfeeding?

Not recommended in pregnancy or while breastfeeding.

Does Chlorzoxazone need a prescription in India?

Yes. In India it is a prescription (Schedule H) medicine, so a pharmacist should sell it only with a doctor's prescription.

Which brands contain Chlorzoxazone?

Hifenac-MR, Myospaz Forte.

Sources and further reading

NHS (UK National Health Service) and MedlinePlus (US National Library of Medicine) are free, reviewed medicine guides. Brand names and doses there may differ from India.

Last reviewed 31 October 2026. Written by Satya Babu from standard prescribing information.

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For information only, not medical advice. This page is a plain-language summary written from standard prescribing information and the public guides linked below. Brands sometimes change their formula, so always check the composition printed on the pack. Doses here are typical adult doses; yours may differ. Do not start, stop or change a medicine without your doctor or pharmacist, and keep all medicines away from children. In an emergency, call 112 (India) or your local emergency number.