--Lidocaine/Lignocaine: CNS disturbances, cardiovascular disturbances, allergic reactions, methaemoglobinaemia. Chlorhexidine Gluconate: Skin irritation, eye irritation, discoloration of teeth, hypersensitivity reactions. Metronidazole: Nausea, metallic taste, dry mouth, glossitis, stomatitis, pancreatitis, encephalopathy, peripheral neuropathy, epileptic seizures, dizziness, headache, syncope, ataxia, vertigo, incoordination, insomnia, irritability, depression, weakness, confusion, hallucinations, convulsions, transient visual disturbances, rash, pruritus, urticaria, flushing, fever, angioedema, anaphylactic shock, pseudomembranous colitis, nausea, epigastric distress, vomiting, diarrhoea, constipation, abdominal cramping, unpleasant metallic taste, furred tongue, anorexia.