The FDA has approved the use of dalfampridine (4-aminopyridine; Ampyra – Acorda), a potassium channel blocker, to improve walking speed in patients with multiple sclerosis (MS). Walking speed is considered a reliable clinical measure of impairment in patients with MS.

The FDA has approved ocrelizumab (Ocrevus – Genentech), a humanized anti-CD20 monoclonal antibody, for treatment of adults with primary progressive or relapsing multiple sclerosis (MS). It is the first anti-CD20 monoclonal antibody to be approved for treatment of MS and the first disease-modifying drug to be approved in the US for primary progressive MS.

The FDA has required a new boxed warning in the label of the subcutaneously injected immunomodulatory drug glatiramer acetate (Copaxone, Glatopa, and generics) about a risk of anaphylaxis. Glatiramer has been used for years to treat relapsing forms of multiple sclerosis (MS).

The FDA has approved Nuedexta (Avanir), a fixed-dose combination of the cough suppressant dextromethorphan hydrobromide and the antiarrhythmic quinidine sulfate, for oral treatment of pseudobulbar affect. The combination is the first treatment approved by the FDA for this indication. Studies to support the effectiveness of Nuedexta were performed in patients with underlying amyotrophic lateral sclerosis (ALS) or multiple sclerosis (MS); the drug has not been shown to be safe or effective in other types of emotional lability.

Tizanidine (Zanaflex - Athena Neurosciences) has been approved by the US Food and Drug Administration for oral treatment of increased muscle tone associated with spasticity. It has been available in Europe and Japan for 12 years as a short-term muscle relaxant.

Cannabis (marijuana) contains more than 60 pharmacologically active cannabinoids; delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the best known. THC is the main psychoactive constituent of cannabis. CBD, unlike THC, does not produce intoxication or euphoria.

An intrathecal formulation of the muscle relaxant baclofen (Lioresal Intrathecal - Medtronic) has been approved by the US Food and Drug Administration for treatment of spasticity due to multiple sclerosis (MS) or spinal cord injury. Its use requires subcutaneous implantation of a drug pump, which infuses the drug into the subarachnoid space. Baclofen (Lioresal [Ciba-Geigy], and others) has been available as an oral formulation for many years (Medical Letter 20:43, 1978), but its use has been limited by central-nervous-system effects such as drowsiness and confusion.

The February 14th issue of The Medical Letter reviewed natalizumab (Tysabri - Biogen Idec), a new monoclonal antibody that was granted accelerated approval because it decreased the number of relapses in patients with multiple sclerosis. On February 28th, the FDA issued a Public Health Advisory announcing that marketing of the drug had been suspended because 2 patients who had been treated with natalizumab for more than 2 years had developed progressive multifocal leukoencephalopathy, a rare, often fatal disease...

Carnitine is a naturally occurring amino acid derivative essential for transport of long-chain fatty acids into mitochondria. It is advertised on the Internet as a dietary supplement that can promote weight loss, increase energy, enhance athletic performance and slow aging. Levocarnitine (Carnitor - Sigma-Tau) has been FDA approved for oral and parenteral treatment of primary carnitine deficiency since 1986. Products containing levocarnitine and its synthetic derivative acetyl-L-carnitine are available as dietary supplements in the US.

Soon after The Medical Letter first reviewed use of natalizumab (Tysabri – Biogen Idec and Elan) for treatment of relapsing forms of multiple sclerosis (MS) (Med Lett Drugs Ther 2005; 47:13), the drug was withdrawn from the market. The unpublished clinical trials that led to its approval by the FDA have since been published, and now the drug has been returned to the market with prescribing restrictions.Natalizumab decreases the number of relapses and new brain lesions in patients with MS. It was withdrawn because progressive multifocal leukoencephalopathy (PML) occurred in 3 (of about 3000)...