INN monograph
Chlorzoxazone / Paracetamol / Ibuprofen
Muscle Relaxant [EPC] · POM
Source-linked · Updated 03 Aug 2026 · Source: Local active-ingredient clinical extract; FDA drug label via OpenFDA/DailyMed; Component monographs (multi-source pipeline); Professional class pharmacology (Non-opioid analgesic / antipyretic)
Kenya market
Wholesale / list prices where loaded
Risk first
Contraindications
- [Chlorzoxazone] Hypersensitivity to the active substance or excipients.
- Additional absolute contraindications are indication- and product-specific — consult SmPC. [Paracetamol] Severe active hepatic disease / acute liver failure.
- Hypersensitivity.
- Chronic heavy alcohol use — use reduced maximum daily dose or avoid. [Ibuprofen] Active peptic ulcer / GI bleeding.
- Severe heart failure.
- NSAID-exacerbated respiratory disease (aspirin-sensitive asthma) for non-selective agents.
- Third trimester pregnancy (ductus arteriosus, oligohydramnios — class warning).
- Severe renal impairment for many agents.
- Hypersensitivity to NSAIDs.
Precautions
- WARNINGS Serious (including fatal) hepatocellular toxicity has been reported rarely in patients receiving chlorzoxazone.
- The mechanism is unknown but appears to be idiosyncratic and unpredictable.
- Factors predisposing patients to this rare event are not known.
- Patients should be instructed to report early signs and/or symptoms of hepatotoxicity such as fever, rash, anorexia, nausea, vomiting, fatigue, right upper quadrant pain, dark urine, or jaundice.
- Chlorzoxazone should be discontinued immediately and a physician consulted if any of these signs or symptoms develop.
- Chlorzoxazone use should also be discontinued if a patient develops abnormal liver enzymes (e.g., AST, ALT, alkaline phosphatase and bilirubin.) The concomitant use of alcohol or other central nervous system depressants may have an additive effect.
- Usage in Pregnancy The safe use of chlorzoxazone has not been established with respect to the possible adverse effects upon fetal development.
- Therefore, it should be used in women of childbearing potential only when, in the judgment of the physician, the potential benefits outweigh the possible risks.
Point of care
Dosing
Adult
DOSAGE AND ADMINISTRATION Usual Adult Dosage One tablet three or four times daily. If adequate response is not obtained with this dose, it may be increased to one and one-half tablets (750 mg) three or four times daily. As improvement occurs dosage can usually be reduced.
Paediatric
See label paediatric section if present; otherwise use paediatric formulary — do not extrapolate adult doses.
Renal
Generally safe; prolonged high dose rare associations — prefer careful use in advanced CKD.
- CrCl 0–120: Confirm renal dosing in product SmPC / primary label.
Hepatic
PRIMARY toxicity organ in overdose; therapeutic doses usually safe if daily limits respected.
Safety
Drug interactions
- Fixed-dose/multi-ingredient product.
- Clinical details partially inherited from component monographs: Chlorzoxazone, Paracetamol, Ibuprofen.
- Confirm combination SmPC for exact dosing.
Safety
Adverse effects
- ADVERSE REACTIONS Chlorzoxazone containing products are usually well tolerated.
- It is possible in rare instances that chlorzoxazone may have been associated with gastrointestinal bleeding.
- Drowsiness, dizziness, lightheadedness, malaise, or over-stimulation may be noted by an occasional patient.
- Rarely, allergic type skin rashes, petechiae, or ecchymoses may develop during treatment.
- Angioneurotic edema or anaphylactic reactions are extremely rare.
- There is no evidence that the drug will cause renal damage.
- Rarely, a patient may note discoloration of the urine resulting from a phenolic metabolite of chlorzoxazone.
- This finding is of no known clinical significance.
- To report SUSPECTED ADVERSE EVENTS, contact Aurobindo Pharma USA, Inc. at 1-866-850-2876 or FDA at 1-800- FDA-1088 or http://www.fda.gov/ for voluntary reporting of adverse reactions.
Use
Indications
- INDICATIONS Chlorzoxazone is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions.
- The mode of action of this drug has not been clearly identified, but may be related to its sedative properties.
- Chlorzoxazone does not directly relax tense skeletal muscles in man.
Pharmacology
Mode of action
Combination product.
Full mechanism text
Combination product. Component mechanism (Paracetamol): Inhibitors of cyclo-oxygenase [COX-1 and COX-2] enzyme that catalyzes the conversion of arachidonic acid to PGH2.
ADME
Pharmacokinetics & PD
| Onset | 30–60 minutes oral |
|---|---|
| Duration | 4–6 hours |
| Route | ORAL / RECTAL / IV |
Full PK/PD text
CLINICAL PHARMACOLOGY Chlorzoxazone is a centrally-acting agent for painful musculoskeletal conditions. Data available from animal experiments as well as human study indicate that chlorzoxazone acts primarily at the level of the spinal cord and subcortical areas of the brain where it inhibits multisynaptic reflex arcs involved in producing and maintaining skeletal muscle spasm of varied etiology. The clinical result is a reduction of the skeletal muscle spasm with relief of pain and increased mobility of the involved muscles. Blood levels of chlorzoxazone can be detected in people during the first 30 minutes and peak levels may be reached, in the majority of the subjects, in about 1 to 2 hours after oral administration of chlorzoxazone. Chlorzoxazone is rapidly metabolized and is excreted in the urine, primarily in a conjugated form as the glucuronide. Less than one percent of a dose of chlorzoxazone is excreted unchanged in the urine in 24 hours.
Kenya
Brands & prices
| Brand | Company | Pack | KES |
|---|---|---|---|
| No brands linked yet. | |||
Special populations
Pregnancy & lactation
Pregnancy
[Chlorzoxazone] Use only if potential benefit justifies potential risk; prefer agents with better reproductive data when alternatives exist. [Paracetamol] Analgesic/antipyretic of choice in pregnancy when needed; use lowest effective dose/shortest duration. [Ibuprofen] Avoid in third trimester. Earlier pregnancy: use only if needed; prefer paracetamol first-line.
Lactation
[Chlorzoxazone] Assess infant risk vs benefit of maternal therapy; prefer agents with lactation data. [Ibuprofen] Short-course ibuprofen generally acceptable; avoid chronic high-dose/long half-life agents when possible.
Diet
Food & alcohol
- Food
- Food
Trust
Sources & disclaimer
Source: Local active-ingredient clinical extract; FDA drug label via OpenFDA/DailyMed; Component monographs (multi-source pipeline); Professional class pharmacology (Non-opioid analgesic / antipyretic)
Clinical review date not recorded.
Decision support only — not a substitute for clinical judgment, product SmPC, or Kenya STG/EML.