This is a big topic and I will do my best to do it justice. Cortisone/cortisol (cortisol is naturally occurring and cortisone is synthesised) was first identified by chemists researching at the Mayoclinic in 1929. It was discovered that large doses of injected cortisone was effective in treating patients with severe rheumatoid arthritis and in 1950 the scientists won the Nobel prize for Physiology or Medicine for the discovery of the structure and function of adrenal cortex hormones including cortisol. It was first produced commercially by Merck and is now given intravenously, orally, inhaler, eye drops, intra-articularly (in a joint) and transcutaneously. Cortisone is converted to cortisol in the liver and it is used for a variety of ailments like arthritis, blood/hormone/immune system disorders, allergic reactions, skin and eye conditions, respiratory conditions and some cancers.
This is part of the family of corticosteroids, otherwise including hydrocortisone and prednisone. When prescribed in doses higher than our bodies usual levels it suppresses inflammation (finding benefit in treating inflammatory conditions). They also suppress the immune system and therefore going a long way to manage some auto-immune diseases.
The Good:
treat allergic reactions/disorders
manages some auto-immune disorders
treatment of skin conditions
treatment of inflammatory arthritis
treat persons with adrenal insufficiencies
treat and manage respiratory conditions like asthma
temporary relief of inflammatory pain like tendonitis
The Bad (short term):
fluid retention
high blood pressure
psychological problems
upset stomach
weight gain
thrush
thinning skin
slow down healing
The Ugly (long term):
glaucoma
swollen face (moon face)
high blood sugar
recurrent infections
thinning/weakening bones, tendons
skin conditions, thinning, bruising, poor healing
liver damage
increased blood clots
other
Cortisone is a wonder drug of sorts, it can make people feel so much better that are really suffering but it can also be very damaging if used chronically and misused. Long term use requires strict medical management and supervision.
I think it is worth deeper dive into the use of cortisone injections for tendon injury or inflammation as this is a commonly used as a "quick fix". Examples include shoulder tendinopathy, tennis elbow and achilles tendinopathy and trigger finger - of which trigger finger is the only one where there is good evidence to support it as a treatment, yet it still remains one of the most common treatments.
Evidence does show that cortisone injections do offer temporary relief to tendinopathy. What is not widely noted is that it is NOT long lasting relief and it can cause further weakening and more chronic tendon complications in the longer term. The cost outweighs the benefit, not unless you engage with targeted rehabilitation to that tendon to assist in rebuilding it.
Tendinopathy is not nice. It can take a long time to heal and most people struggle to put in the time and effort required. It may be tempting to turn to a quick fix, but know that nothing beats good old fashioned hard work!