Usage
- Chlorzoxazone + Diclofenac is prescribed for the relief of acute, painful musculoskeletal disorders accompanied by muscle spasms. Conditions such as sprains, strains, and other muscle injuries can benefit from this combination therapy.
- Pharmacological Classification: This drug is a combination of a skeletal muscle relaxant (Chlorzoxazone) and a nonsteroidal anti-inflammatory drug (NSAID) (Diclofenac). It also has analgesic and antipyretic properties.
- Mechanism of Action: Chlorzoxazone acts centrally on the spinal cord and subcortical areas of the brain to inhibit multisynaptic reflex arcs involved in muscle spasm. Diclofenac inhibits cyclooxygenase (COX) enzymes, reducing the production of prostaglandins which are mediators of pain and inflammation.
Alternate Names
- This combination is often referred to as Diclofenac + Chlorzoxazone.
- Brand Names: Some common brand names including this combination are Diclozone K, Myospaz Forte and DICLOTAL+ MR, though formulations may also include Paracetamol.
How It Works
- Pharmacodynamics: Chlorzoxazone decreases muscle excitability, leading to reduced muscle spasm and pain. Diclofenac reduces pain and inflammation by inhibiting prostaglandin synthesis.
- Pharmacokinetics: Both Chlorzoxazone and Diclofenac are well absorbed orally. Chlorzoxazone is metabolized in the liver, primarily via CYP2E1, and excreted in the urine as glucuronide conjugates. Diclofenac is also metabolized in the liver, primarily by CYP2C9, with elimination via renal and biliary routes.
- Mode of Action: Chlorzoxazone acts centrally on the spinal cord and brain, while Diclofenac peripherally inhibits COX-1 and COX-2 enzymes, leading to decreased prostaglandin production. This combination provides both central muscle relaxation and peripheral pain and inflammation reduction.
- Elimination Pathways: Chlorzoxazone is primarily excreted through hepatic (liver) metabolism and renal (kidney) excretion, while Diclofenac is eliminated through both renal (kidney) and biliary (liver) excretion.
Dosage
Standard Dosage
Adults:
- One tablet two or three times a day with food.
- Maximum dosage of Diclofenac is 150 mg/day and that of Chlorzoxazone is 3000 mg/day.
Children:
- Use is generally not recommended for children under 12 years of age. Dosages must be determined by the healthcare provider and closely monitored if prescribed.
- Pediatric safety concerns exist due to limited data and the potential for adverse effects.
Special Cases:
- Elderly Patients: Lower doses may be necessary due to age-related decline in kidney and liver function. Close monitoring for side effects is crucial.
- Patients with Renal Impairment: Dose adjustment is necessary based on the degree of impairment. Consult medical guidelines for appropriate dosage modifications.
- Patients with Hepatic Dysfunction: Similar to patients with renal impairment, dose adjustments are required for hepatic dysfunction. Monitor liver function tests regularly.
- Patients with Comorbid Conditions: Dose adjustments may be needed for patients with other conditions such as cardiovascular disease, diabetes, or GI issues.
Clinical Use Cases
The use of Chlorzoxazone + Diclofenac is not specifically indicated for clinical use cases such as intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. The drug is primarily indicated for the management of musculoskeletal pain and muscle spasms. If required for pain management in such scenarios, use should be under strict supervision, following dosage adjustments based on the specific situation and patient status.
Dosage Adjustments
Dosage adjustments should be based on kidney function, liver function, presence of other diseases, and age.
Side Effects
Common Side Effects
- Drowsiness, dizziness, lightheadedness
- Nausea, vomiting, abdominal discomfort
- Constipation, diarrhea
Rare but Serious Side Effects
- Allergic reactions (skin rash, itching, swelling)
- Liver damage (jaundice, dark urine)
- Kidney problems (changes in urine output)
- Gastrointestinal bleeding (black stools, vomiting blood)
- Cardiovascular events (chest pain, shortness of breath)
Long-Term Effects
- Potential liver and kidney damage with prolonged use
- Gastrointestinal problems
Adverse Drug Reactions (ADR)
Severe allergic reactions, liver failure, acute kidney injury, and serious gastrointestinal bleeding are potential ADRs.
Contraindications
- Hypersensitivity to chlorzoxazone or diclofenac
- Active peptic ulcer or gastrointestinal bleeding
- Severe hepatic or renal impairment
- Aspirin triad (asthma, nasal polyps, aspirin sensitivity)
Drug Interactions
- Other NSAIDs, anticoagulants, antihypertensives
- Alcohol, CNS depressants
- Methotrexate, lithium
Pregnancy and Breastfeeding
- Use in pregnancy is not recommended, especially during the third trimester.
- Use during breastfeeding is not advisable as small quantities may be present in breastmilk, consult a doctor before using.
Drug Profile Summary
- Mechanism of Action: Centrally acting muscle relaxant and peripherally acting NSAID.
- Side Effects: Drowsiness, dizziness, gastrointestinal issues, liver/kidney toxicity.
- Contraindications: Hypersensitivity, peptic ulcer, severe liver/kidney disease.
- Drug Interactions: NSAIDs, anticoagulants, alcohol.
- Pregnancy & Breastfeeding: Not recommended during pregnancy, especially during the third trimester and breastfeeding.
- Dosage: As per healthcare provider, 1 tablet twice daily (up to three times daily). Consider lower doses for elderly and patients with renal/hepatic impairment.
- Monitoring Parameters: Liver function tests, kidney function tests, signs of gastrointestinal bleeding.
Popular Combinations
This drug is sometimes combined with Paracetamol/Acetaminophen for enhanced pain relief.
Precautions
- General Precautions: Monitor for liver and kidney function, gastrointestinal bleeding.
- Specific Populations: Avoid or adjust dosage in elderly, pregnant/lactating women, and patients with renal/hepatic impairment.
- Lifestyle Considerations: Avoid alcohol; caution with driving.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Chlorzoxazone + Diclofenac?
A: The recommended adult dosage is typically one tablet two or three times a day, with food. This can vary based on individual patient factors and the specific formulation. Pediatric use is generally not recommended.
Q2: What are the common side effects?
A: Common side effects include drowsiness, dizziness, nausea, vomiting, and gastrointestinal discomfort.
Q3: Who should not take this medication?
A: Individuals with hypersensitivity to the drug components, active peptic ulcer, severe liver or kidney disease, or aspirin triad should not take this medication.
Q4: Are there any drug interactions I should be aware of?
A: Yes, this drug can interact with other NSAIDs, anticoagulants, antihypertensives, alcohol, and CNS depressants.
Q5: Can I take this medication if I am pregnant or breastfeeding?
A: This medication is generally not recommended during pregnancy, especially during the third trimester, or breastfeeding. If considering use during breastfeeding, discuss with your doctor first.
Q6: What are the signs of an allergic reaction to this drug?
A: Signs of an allergic reaction include skin rash, itching, hives, swelling of the face, lips, or tongue, difficulty breathing, and dizziness.
Q7: How should this medication be stored?
A: Store at room temperature, away from moisture, heat, and direct sunlight. Keep out of reach of children.
Q8: What should I do if I miss a dose?
A: If you miss a dose, take it as soon as you remember. However, if it is close to the time for your next dose, skip the missed dose and continue your regular dosing schedule. Do not double the dose to catch up.
Q9: Can I drink alcohol while taking Chlorzoxazone + Diclofenac?
A: No, it is advisable to avoid alcohol while taking Chlorzoxazone + Diclofenac, as it can increase the risk of side effects such as drowsiness and dizziness, and may also exacerbate the risk of gastrointestinal issues.
Q10: Can this medication affect my ability to drive or operate machinery?
A: Due to its potential to cause drowsiness and dizziness, this medication may impair your ability to drive or operate machinery. Caution is advised, and activities requiring alertness should be avoided until you know how this medication affects you.
