Synject 20mg injection contains an active ingredient called Sodium Hyaluronate, which belongs to the group of medicines called intra-articular agents. It is like the natural fluid that cushions your joints, which helps lubricate and protect your joints, acting as a shock absorber. This medicine relieves knee pain in patients with osteoarthritis (OA). It is usually given to patients who have not responded well to the other arthritis medications. Do not use Synject 20mg injection if you are allergic to Sodium Hyaluronate or any of its ingredients. Do not use this medication if you have an infection in your knee or in the skin around your knee. Before taking the medicine, notify your doctor if you have had a history of blood clots or circulation issues in your legs or if you have an allergy to birds, feathers, or egg products. Report to your doctor if you have pre-existing chondrocalcinosis (cartilage calcification). Not recommended for children aged 21 years and younger as its safety and effectiveness have not been proven. Before start taking Synject 20mg injection, inform your doctor if you are pregnant, planning to get pregnant, or think you may be pregnant or breastfeeding. Notify your doctor if you have a history of any disease. The common side effects of the medicine are pain, redness, stiffness, bruising, or puffiness at the injection site, nausea, stomach pain, trouble walking, back pain, joint pain, muscle pain, numbness or tingling, headache, dizziness, and a runny or stuffy nose.