Usage
This combination liniment is prescribed for the short-term relief of pain and inflammation associated with musculoskeletal and joint disorders such as:
- Muscle strains and sprains
- Arthritis (osteoarthritis and rheumatoid arthritis)
- Back pain (low back pain)
- Stiff neck
- Sports injuries
- Bruises
Pharmacological Classification:
This liniment is a combination of drugs from several classes including:
- Topical non-steroidal anti-inflammatory drug (NSAID) - Diclofenac
- Topical analgesic and rubefacient - Capsaicin, Menthol, Camphor
- Muscle relaxant - Mephenesin
Mechanism of Action:
This liniment employs a multimodal mechanism of action, targeting pain and inflammation through various pathways:
- Diclofenac: Inhibits cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis, thus decreasing pain and inflammation.
- Capsaicin: Depletes substance P, a neurotransmitter involved in pain transmission, leading to desensitization of nociceptors.
- Menthol and Camphor: Act as counterirritants, causing vasodilation and a cooling sensation that distracts from pain perception. They also enhance the penetration of other topical agents.
- Mephenesin: Acts centrally on the spinal cord and brainstem to reduce muscle spasm and stiffness.
Alternate Names
This combination is marketed under various brand names including:
- Doil-MR Liniment
- Fenlong MR Liniment
- Fixoil Liniment
How It Works
Pharmacodynamics:
The combined effects of the ingredients provide analgesic, anti-inflammatory, and muscle relaxant properties. Diclofenac reduces pain and inflammation. Capsaicin desensitizes pain receptors. Menthol and camphor act as counterirritants and enhance drug penetration. Mephenesin relaxes muscles and relieves spasms.
Pharmacokinetics:
- Absorption: The drug is absorbed through the skin into the underlying tissues. The extent of systemic absorption is generally low.
- Metabolism: Diclofenac is primarily metabolized in the liver by CYP enzymes. The metabolism of the other ingredients is less well-characterized.
- Elimination: Diclofenac metabolites are primarily excreted in the urine. Other components are likely excreted through renal and/or hepatic pathways.
Mode of Action:
- Receptor Binding/Enzyme Inhibition/Neurotransmitter Modulation: See Mechanism of Action above.
- Elimination Pathways: Primarily renal and hepatic.
Dosage
Standard Dosage
Adults:
Apply 15-30 drops to the affected area and gently massage until absorbed. Repeat 2-4 times daily as directed by the physician.
Children:
Not recommended for children under 14 years of age.
Special Cases:
- Elderly Patients: Use with caution due to increased risk of systemic absorption. Dosage adjustments may be necessary.
- Patients with Renal Impairment: Use with caution. Dosage adjustment may be needed.
- Patients with Hepatic Dysfunction: Use with caution. Dose modification may be required.
- Patients with Comorbid Conditions (e.g., asthma, high blood pressure, diabetes, cardiovascular disease, bleeding disorders, peptic ulcer disease): Close monitoring is required, and dose adjustments may be necessary. Caution is advised, especially in patients with a history of hypersensitivity to NSAIDs.
Clinical Use Cases
This medication is not intended for clinical settings such as intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. It is for topical application only for musculoskeletal pain.
Dosage Adjustments
Adjustments may be necessary based on individual patient factors, including renal or hepatic impairment, other medical conditions, and concomitant medications. Consult a physician to determine the appropriate dose modification.
Side Effects
Common Side Effects:
- Itching
- Redness
- Irritation
- Burning sensation at the application site
Rare but Serious Side Effects:
- Allergic reactions (e.g., rash, hives, difficulty breathing, swelling of face, lips, tongue, or throat)
- Severe skin reactions (e.g., blistering, peeling)
- Systemic effects of diclofenac (e.g., gastrointestinal bleeding, kidney problems)
Long-Term Effects:
Data on long-term effects is limited. Prolonged use can potentially lead to skin irritation or sensitization. Systemic effects are less likely with topical use but cannot be entirely ruled out.
Adverse Drug Reactions (ADR):
See Rare but Serious Side Effects above.
Contraindications
- Hypersensitivity to any component of the medication
- Third trimester of pregnancy
- Open wounds, broken skin, or irritated skin
- Patients with a history of aspirin-sensitive asthma
Drug Interactions
- Oral NSAIDs: Increased risk of systemic side effects.
- Anticoagulants: Increased risk of bleeding.
- Antihypertensives: May reduce the efficacy of antihypertensives.
- CYP450 Interactions: Diclofenac is metabolized by CYP enzymes, primarily CYP2C9. Enzyme inducers or inhibitors may affect diclofenac levels. The other ingredients have less well-characterized metabolic pathways.
Pregnancy and Breastfeeding
- Pregnancy: Not recommended during the third trimester. Use during the first and second trimesters only if clearly needed and under close medical supervision.
- Breastfeeding: Use with caution as there is potential for neonatal exposure through breast milk.
Drug Profile Summary
Refer to the dedicated sections above for this information.
Popular Combinations
This combination is itself a popular formulation. Additional drug combinations for topical application with this product are not typically recommended.
Precautions
- Avoid contact with eyes, mucous membranes, and broken skin.
- Wash hands thoroughly after application.
- Do not apply heat or use occlusive bandages.
- Avoid exposure to sunlight or UV radiation on treated areas.
- Monitor for signs of systemic absorption.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Camphor + Capsaicin + Diclofenac + Menthol + Mephenesin?
A: Apply 15-30 drops to the affected area 2-4 times daily.
Q2: Can this liniment be used during pregnancy?
A: It is not recommended during the third trimester. Use during the first and second trimesters only if clearly needed and under close medical supervision.
Q3: Can it be used while breastfeeding?
A: Use with caution as there is potential for neonatal exposure through breast milk.
Q4: What are the common side effects?
A: Common side effects include itching, redness, irritation, and a burning sensation at the application site.
Q5: Are there any serious side effects?
A: Rare but serious side effects can include allergic reactions, severe skin reactions, and systemic effects of diclofenac (e.g., gastrointestinal bleeding).
Q6: What should I do if a patient experiences side effects?
A: Discontinue use and consult a physician. For serious reactions, seek immediate medical attention.
Q7: Can this liniment be used on broken skin?
A: No, it should not be applied to open wounds, broken skin, or irritated skin.
Q8: Are there any drug interactions I should be aware of?
A: Yes, it can interact with oral NSAIDs, anticoagulants, and antihypertensives. Inform patients to disclose all medications they are taking, including OTC drugs and supplements.
Q9: How does this liniment work to relieve pain?
A: It utilizes a multimodal approach. Diclofenac reduces inflammation, capsaicin desensitizes pain receptors, menthol and camphor provide counterirritation, and mephenesin relaxes muscles.
