Intravenous immunoglobulin (IVIG) has 6 FDA approved indications and is prescribed off-label for many others. How many of these uses are justified is controversial.

Fourteen states in the US - Alaska, California, Colorado, Hawaii, Maine, Michigan, Montana, Nevada, New Jersey, New Mexico, Oregon, Rhode Island, Vermont and Washington - now permit, or soon will permit, some medical use of marijuana (Cannabis sativa). In some states, licensed facilities dispense botanical cannabis by prescription. In others, limited self-cultivation is permitted for medical use.

Gabapentin (Neurontin - Pfizer), which has been available in the US since 1994, is approved by the FDA only for treatment of partial epilepsy and postherpetic neuralgia, but is widely used off-label for a number of other indications, especially neuropathic pain syndromes. According to one report, among Medicaid recipients in Florida receiving gabapentin, 71% of prescriptions were for chronic pain and 8% for seizures and neuralgia ("The Pink Sheet" February 2, 2004; 66:30).

Dehydroepiandrosterone (DHEA) is an adrenal androgen now being marketed as a "food supplement"in health food stores. DHEA is not approved for any indication by the US Food and Drug Administration (FDA).

The oral sphingosine 1-phosphate (S1P) receptor modulator ozanimod (Zeposia – Bristol Myers Squibb) has been approved by the FDA for treatment of adults with moderately to severely active ulcerative colitis. It is the first S1P receptor modulator to be approved for treatment of ulcerative colitis. Ozanimod was approved in March 2020 for use in adults with relapsing forms of multiple sclerosis.

A synthetic form of the protein apoaequorin is the active ingredient in the over-the-counter dietary supplement Prevagen (Quincy Bioscience), which is heavily marketed to improve memory.

Some tumor necrosis factor (TNF) inhibitors are being promoted on the internet directly to the public for use in psoriasis (www.yahoo.com).

Certolizumab pegol (Cimzia – UCB), a tumor necrosis factor (TNF) inhibitor previously approved for treatment of Crohn's disease and rheumatoid arthritis, and ustekinumab (Stelara – Janssen), a human interleukin-12 and -23 antagonist previously approved for treatment of moderate-to-severe plaque psoriasis, have now been approved by the FDA for treatment of active psoriatic arthritis.

The FDA has approved golimumab (Simponi – Janssen), a fully human monoclonal antibody specific for tumor necrosis factor (TNF) alpha, for induction and maintenance of remission in patients with moderate to severe ulcerative colitis who do not respond to or cannot tolerate other therapies or who require continuous treatment with corticosteroids. Golimumab was approved earlier for treatment of rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis. It is the third TNF inhibitor to be approved for use in ulcerative colitis.

The FDA has recently approved intradetrusor injection of onabotulinumtoxinA (Botox – Allergan) for treatment of overactive bladder in patients who cannot tolerate or have an inadequate response to anticholinergic therapy. Botox is also approved by the FDA for use in detrusor overactivity associated with a neurologic condition such as multiple sclerosis or spinal cord injury, and for chronic migraine, upper limb spasticity, axillary hyperhidrosis, cervical dystonia, blepharospasm, strabismus, and cosmetic reduction of wrinkles.