1. Clinical Overview
A topical analgesic and anti-inflammatory combination used for the relief of mild to moderate pain and inflammation associated with musculoskeletal conditions. Choline salicylate is a non-steroidal anti-inflammatory drug (NSAID) that provides anti-inflammatory and analgesic effects, while lidocaine is a local anesthetic that provides rapid pain relief by blocking nerve conduction.
| Onset | Duration | Bioavailability |
|---|---|---|
| Lidocaine: 3-5 minutes; Choline Salicylate: 30-60 minutes for anti-inflammatory effect. | Lidocaine: 1-2 hours; Choline Salicylate: 4-6 hours. | Topical: Variable, estimated <10% systemic absorption for both components when applied to intact skin. |
2. Mechanism of Action
The combination works via two distinct mechanisms. Lidocaine blocks voltage-gated sodium channels on neuronal membranes, inhibiting the initiation and conduction of nerve impulses, leading to localized numbness. Choline salicylate, after conversion to salicylic acid, inhibits the cyclooxygenase (COX) enzymes, particularly COX-1 and COX-2, thereby reducing the synthesis of prostaglandins, which are mediators of pain, inflammation, and fever.
3. Indications & Uses
- Localized pain and inflammation of musculoskeletal origin (e.g., sprains, strains)
- Osteoarthritis of superficial joints (knee, elbow)
- Myalgia (muscle pain)
- Non-articular rheumatism
4. Dosage & Administration
Adult Dosage: Apply a thin layer (2-4 g, approx. 1-2 inches of gel) to the affected area 3 to 4 times daily. Gently rub in. Do not apply more than 4 times in 24 hours.
Administration: For external use only. Wash hands before and after application. Apply to clean, dry, intact skin. Do not cover with occlusive dressings unless advised by a doctor. Do not apply near eyes, mouth, genital areas, or on mucous membranes. Do not use with heating pads.
5. Side Effects
Common side effects may include:
- Application site reactions: Burning, stinging, itching, erythema (redness)
- Dry skin
- Mild skin rash
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Anticoagulants (Warfarin, Acenocoumarol) | Increased risk of bleeding due to antiplatelet effect of salicylate. | Major |
| Other Oral NSAIDs (Ibuprofen, Diclofenac) | Increased risk of GI toxicity and renal impairment. May diminish cardioprotective effect of aspirin. | Major |
| Methotrexate | Salicylate may decrease renal clearance of methotrexate, increasing toxicity risk. | Major |
| Lithium | Salicylate may decrease renal clearance of lithium, leading to toxicity. | Major |
| ACE Inhibitors (Enalapril, Ramipril) | Salicylate may reduce antihypertensive efficacy. | Moderate |
| Diuretics (Furosemide) | Risk of reduced diuretic and antihypertensive effect; potential for nephrotoxicity. | Moderate |
| Antiepileptics (Phenytoin, Carbamazepine) | Lidocaine toxicity risk may increase due to CYP competition. | Moderate |
| Beta-blockers (Propranolol) | May increase risk of lidocaine toxicity by reducing hepatic blood flow. | Moderate |
7. Patient Counselling
- DO use only on intact skin as directed.
- DO wash hands before and after application.
- DO inform your doctor if you are pregnant, planning pregnancy, or breastfeeding.
- DON'T apply to open wounds, broken skin, or mucous membranes.
- DON'T cover the area with tight bandages or plastic wraps unless instructed.
- DON'T use with a heating pad, as it increases absorption and risk of burns.
- DON'T use for more than 7 days for pain or 3 days for inflammation without medical advice.
8. Toxicology & Storage
Overdose: Topical Overuse: Symptoms of salicylism (tinnitus, vertigo, headache, confusion, hyperventilation, metabolic acidosis). Lidocaine toxicity: CNS (dizziness, perioral numbness, tinnitus, seizures, coma); Cardiovascular (bradycardia, hypotension, cardiac arrest).
Storage: Store at room temperature (15-30°C). Keep the tube tightly closed. Protect from light and moisture. Do not freeze. Keep out of reach of children and pets. Do not use after the expiry date printed on the pack.