Whether diclofenac sodium lasts for 12 hours or 24 hours cannot be determined. It depends on the specific dosage, the mode of administration and the severity of the disease, and other factors, and there are individual differences that cannot be generalized. Diclofenac sodium is a non-steroidal anti-inflammatory drug with fast onset of action, mainly through the inhibition of prostaglandin synthesis to produce analgesic, anti-inflammatory and antipyretic effects, mainly for the relief of various arthritic joint swelling and pain symptoms, synovitis, bursitis, and acute mild to moderate pain, etc. Diclofenac sodium has a strong analgesic effect and is absorbed quickly in the gastrointestinal tract after oral administration. The analgesic effect usually appears in about half an hour after taking the drug, and usually lasts for 4-6 hours if it is an enteric tablet or a regular tablet, but the effect is slightly longer if it is an extended-release tablet, which may last for about a day, but the exact time depends on the dosage. Usually, diclofenac sodium can be taken once a day, but it should be used properly under the guidance of a doctor, not without authorization.