--Diclofenac: Gastrointestinal disturbances, rash, headache, dizziness, nervousness, tinnitus, depression, drowsiness, insomnia, fluid retention, renal dysfunction, hepatotoxicity, blood disorders, hypersensitivity reactions (including anaphylaxis), photosensitivity. Capsaicin: Burning sensation, erythema, stinging, pain. Menthol: Skin irritation, allergic reactions, eye irritation, lung conditions if inhaled. Methyl Salicylate: Rash, hives, itching, difficulty breathing or swallowing, wheezing, ringing or buzzing in the ears, hearing loss, nausea, vomiting, diarrhea, fast breathing, confusion, seizures. Pregabalin: Dizziness, sleepiness, confusion, trouble with memory, poor coordination, dry mouth, constipation, edema, weight gain, blurred vision, abnormal thinking, tremor, twitching, muscle stiffness, increased appetite, fever, upper respiratory tract infection. Note: The above information is based on general observations and may not apply to everyone. Always consult a healthcare provider for possible side effects of medications.