How long do the effects of a cortisone injection shot last?

If you are using a cortisone injection in a joint because of pain the duration of effectiveness depends on the type of cortisone injected (there are short and long acting preparations), and how long the patient rests the joint after injection. Generally you would expect many weeks relief. A good general rule to follow is to give no more that 2-3 injections into the same joint in any given year, and ideally, rest the joint for 1 week after each injection.

Cortisone injections can be used to treat the inflammation of small areas of the body (local injections eg. tendonitis, arthritis), or they can be used to treat inflammation that is widespread throughout the body (systemic injections eg allergy,asthma).