Usage
- Methyl salicylate is primarily prescribed for topical relief of muscle and joint pain associated with conditions like arthritis, rheumatism, backache, sprains, strains, and bruises. It can also be used for minor aches and pains, including those related to fibrositis and lumbago. It is sometimes found in some cosmetic products at low concentrations such as mouthwash, face cream, toothpaste.
- Pharmacological Classification: Topical analgesic, counterirritant, rubefacient.
- Mechanism of Action: Methyl salicylate acts as a counterirritant by stimulating sensory receptors in the skin, creating a sensation of warmth or coolness that distracts from the underlying pain. It also possesses some anti-inflammatory properties due to its relationship to salicylates (aspirin-like compounds).
Alternate Names
- Oil of Wintergreen
- Oil of Sweet Birch
- Betula lenta
- Gaultheria procumbens
- Some brand names (US and other countries): BenGay, Icy Hot, Deep Heat, Thera-Gesic, Tiger Balm, Radian B Muscle Rub
How It Works
- Pharmacodynamics: Methyl salicylate primarily exerts its effects locally at the site of application. It activates TRPA1 receptors, leading to a sensation of warmth or coolness depending on the concentration. It also inhibits cyclooxygenase enzymes, reducing inflammation.
- Pharmacokinetics: When applied topically, methyl salicylate is absorbed through the skin, where it is metabolized to salicylic acid. Absorption is enhanced by heat, exercise, or skin damage. It is then distributed throughout the body, with higher concentrations found in tissues at the application site. Metabolism primarily occurs in the skin and subcutaneous tissues, producing salicylic acid. Salicylic acid can then be further metabolized in the liver. Elimination is primarily renal, with some excretion occurring in bile.
Dosage
Standard Dosage
Adults: Apply a liberal amount to the affected area and massage gently until absorbed. For patches, follow product-specific instructions, usually applying one patch to the affected area for up to 8-12 hours. Do not apply more than 4 times daily. Do not exceed a total of 32 g per day over all affected joints.
Children:
Children younger than 12 years old- use and dose must be determined by a healthcare provider. Some products are not indicated for use under 12 years old. Children 12 years of age and older: as adult dose. For cosmetic products intended for children, check specific concentrations allowed for methyl salicylate in each cosmetic product. For children under 6 month old, no data was available.
Special Cases:
- Elderly Patients: The adult dose is generally appropriate.
- Patients with Renal Impairment: Caution advised; dose adjustment may be necessary. Monitor for signs of salicylate toxicity.
- Patients with Hepatic Dysfunction: Caution advised; dose adjustment may be necessary. Monitor for signs of salicylate toxicity.
- Patients with Comorbid Conditions: Use with caution in patients with asthma, bleeding disorders, or a history of hypersensitivity to salicylates or NSAIDs. For those with diabetes, cardiovascular disease, or other serious medical conditions, consult a healthcare provider.
Clinical Use Cases
Methyl salicylate is typically not used in the clinical settings described (Intubation, Surgical Procedures, Mechanical Ventilation, ICU Use, Emergency Situations). Its use is primarily limited to topical pain relief.
Side Effects
Common Side Effects:
- Mild skin irritation (redness, burning, stinging, itching) at the application site
Rare but Serious Side Effects:
- Severe skin irritation (blistering, swelling, severe redness)
- Allergic reactions (hives, difficulty breathing, swelling of face, lips, or tongue)
- Salicylate toxicity (nausea, vomiting, tinnitus, confusion, hyperventilation, seizures, coma) - especially with overuse or in children
Long-Term Effects:
Prolonged use can potentially lead to skin thinning or discoloration.
Contraindications
- Hypersensitivity to methyl salicylate or any other salicylates/NSAIDs
- Application to broken skin, open wounds, or mucous membranes
- Use in children with chickenpox, flu, or other undiagnosed illnesses, or those recently vaccinated
- Third trimester of pregnancy
- Children under 5 years old (for some products)
- Concurrent anticoagulation therapy
Drug Interactions
- Anticoagulants (warfarin, dabigatran, apixaban, etc.): Increased risk of bleeding
- Other topical medications: Potential for increased skin irritation
- Oral hypoglycemic agents: May enhance hypoglycemic effects
Pregnancy and Breastfeeding
- Pregnancy: Avoid use after 20 weeks of gestation due to potential risk of fetal harm. Use with caution between 20 and 30 weeks if benefits outweigh risks.
- Breastfeeding: Salicylates are excreted in breast milk. Consult a healthcare provider before use during breastfeeding.
Drug Profile Summary
- Mechanism of Action: Counterirritant, analgesic, anti-inflammatory
- Side Effects: Skin irritation, allergic reactions, salicylate toxicity
- Contraindications: Hypersensitivity, broken skin, third trimester of pregnancy
- Drug Interactions: Anticoagulants, other topical medications
- Pregnancy & Breastfeeding: Avoid in third trimester; caution during breastfeeding
- Dosage: Topical application as needed, up to 4 times daily, not to exceed 32 g per day over all affected joints
- Monitoring Parameters: Observe for skin reactions and signs of salicylate toxicity
Popular Combinations
Methyl salicylate is often combined with menthol, camphor, or capsaicin in topical formulations for enhanced pain relief.
Precautions
- For external use only. Avoid contact with eyes, mucous membranes, and broken skin.
- Wash hands thoroughly after application.
- Discontinue use if condition worsens or does not improve within 7 days.
- Monitor for skin reactions and signs of salicylate toxicity.
- Avoid use with occlusive dressings or heating pads.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Methyl Salicylate?
A: Adults and Children 12 years old and above: Apply liberally to the affected area and massage gently up to 4 times a day. For patches, apply one patch to the affected area for 8-12 hours, as per product instructions. Consult a doctor for use in children below 12.
Q2: Can Methyl Salicylate be used during pregnancy?
A: Avoid using methyl salicylate during pregnancy, especially after 20 weeks of gestation, unless specifically directed by a doctor.
Q3: What are the common side effects of Methyl Salicylate?
A: Common side effects include mild skin irritation such as redness, burning, stinging, or itching at the application site.
Q4: Are there any serious side effects I should be aware of?
A: Rare but serious side effects can include severe skin reactions, allergic reactions, and salicylate toxicity, especially with overuse or in children.
Q5: What should I do if I experience side effects?
A: Discontinue use and consult a healthcare professional if you experience any concerning side effects.
Q6: Can Methyl Salicylate interact with other medications?
A: Yes, it can interact with anticoagulants and certain other medications. Inform your doctor about all other medications you are taking.
Q7: Can I use Methyl Salicylate on broken skin?
A: No, avoid applying methyl salicylate to broken skin, open wounds, or mucous membranes.
Q8: Can I use a heating pad after applying Methyl Salicylate?
A: It’s generally not recommended to use heating pads or occlusive dressings after applying Methyl Salicylate, as this can increase absorption and the risk of side effects.
Q9: Is Methyl Salicylate safe for children?
A: It should be used with caution in children younger than 12. Consult with your doctor before using it with young children and follow product recommendations. For children under 6 month old, no data was available.
Q10: What should I do if I accidentally ingest Methyl Salicylate?
A: If ingested, seek immediate medical attention as it can be toxic, particularly to children.
