What Is Acthar (Corticotropin)?

Reviewed by: HU Medical Review Board | Last reviewed: October 2016. | Last updated: October 2020

H.P. Acthar Gel (repository corticotropin injection) is a prescription medication that is used to treat psoriatic arthritis flares at times when symptoms suddenly worsen. Acthar can be an additional, short-term treatment to other ongoing treatments for psoriatic arthritis. Acthar is classified as a hormone, and as such, works with the hormonal system of the body.1,2


Acthar is used to treat a number of conditions, including infantile spasms, episodes of symptoms in people who have multiple sclerosis, lupus, flares of rheumatoid arthritis, flares of psoriatic arthritis, symptoms of sarcoidosis, dermatomyositis, and acute and chronic conditions affecting the eye.1

How Acthar works

Acthar is believed to work with the immune system, helping the body produce the hormone cortisol. Cortisol is produced by the adrenal glands and has anti-inflammatory effects in the body. By reducing the inflammatory response, Acthar helps reduce the pain, swelling and stiffness caused during a flare of psoriatic arthritis.1,2


Acthar comes as a long-acting gel that is injected under the skin (subcutaneously) or into a muscle. It can be self-injected by the patient, or a caregiver or healthcare professional may give the injection. The dosage and frequency are determined for the individual patient by their doctor.1,2

Possible side effects

Common side effects experienced with Acthar are fluid retention, changes in blood sugar, high blood pressure, changes in behavioral and mood, increased or decreased appetite, weight gain, and difficulty falling asleep or staying asleep. Mood changes include irritability, or abnormally happy or excited mood. Some side effects are serious and require immediate medical attention, such as any signs of infection, puffiness or fullness of the face, open cuts or sores, thin skin, increased fat around the neck, stretch marks on the abdomen, thighs or breasts, easy bruising, muscle weakness, stomach pain, vomit that is bloody or blackish, bright red blood in stools, black or tarry stools, depression, difficulty recognizing reality, vision problems, excessive tiredness, increased thirst, fast heartbeat, rash, difficulty breathing, new or different seizures, or swelling of the face, tongue, lips or throat.1,2

Acthar can cause side effects similar to those with steroid treatments. Acthar can increase the risk of infections. After taking Acthar long-term, the adrenal gland may produce too much cortisol, which can cause symptoms of Cushing’s syndrome. Sometimes, after stopping long-term treatment with Acthar, the adrenal glands may not produce enough cortisol on its own, a condition called adrenal insufficiency.1

Other precautions

Acthar should not be taken by people who have scleroderma, osteoporosis, any infections, eye problems, stomach ulcers, heart problems, high blood pressure, allergies to pig-derived proteins, or those who have had recent surgery. People who have a condition that causes their adrenal glands to produce too much or not enough adrenal hormones should not take Acthar 1

Acthar should never be injected directly into a vein.1

Acthar can cause an unpredictable response to vaccines. Patients should talk to their doctor about which vaccines are safe to use with Acthar.1

Using Acthar long-term can affect growth and physical development in children. This can be reversed when Acthar use is discontinued.1

Acthar has been shown to be dangerous to embryos and should be used during pregnancy only if the potential benefit justifies the risk to the unborn child. It is not known whether Acthar is excreted in breast milk. Women who are breastfeeding should discuss the risks and benefits with their doctors.1

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