Leflunomide (Arava - Hoechst Marion Roussel), which inhibits pyrimidine synthesis, and etanercept (Enbrel - Immunex/Wyeth-Ayerst), which blocks the action of tumor necrosis factor (TNF), have been approved by the FDA for treatment of rheumatoid arthritis. A third drug, infliximab (Remicade - Centocor), which also blocks TNF and has been used to treat rheumatoid arthritis, was approved earlier for treatment of Crohn's disease. Its use in Crohn's disease will be reviewed in a future issue.

Amprenavir is the fifth protease inhibitor to become available for treatment of HIV infection. It was approved by the FDA for use with other drugs in the treatment of HIV-infected adults and children at least four years old.

Oxcarbazepine, which is chemically similar to carbamazepine, and levetiracetam, a pyrrolidine acetamide chemically unrelated to other antiepileptic drugs, are the sixth and seventh drugs approved by the US Food and Drug Administration in the last five years for oral use in partial seizures.

Atomoxetine (Strattera - Lilly) is the first non-stimulant drug to be approved by the FDA for treatment of attention deficit hyperactivity disorder (ADHD). Unlike other drugs approved for use in ADHD, it is not a controlled substance and is approved for use in adults as well as children. Older non-stimulant drugs that have been used to treat ADHD, although not FDA-approved, include the alpha₂-agonist clonidine (Catapres, and others) and the tricyclic antidepressant desipramine (Norpramin, and others) (Medical Letter 1996; 38:109).

Rifaximin (Xifaxan - Salix), a non-absorbed oral antibiotic derived from rifampin (Rifadin, and others), has been approved by the FDA for treatment of travelers' diarrhea caused by noninvasive strains of Escherichia coli in patients 12 years of age or older. It has been available in Europe since 1987.

Oxymorphone hydrochloride, a semi-synthetic opioid agonist, has been available for many years in the US as Numorphan (Endo) for parenteral use and as a rectal suppository. Now it has been approved by the FDA for oral administration as an immediate-release (IR) tablet (Opana) for treatment of moderate to severe acute pain, and as an extended-release tablet (Opana ER) for treatment of moderate to severe pain in patients requiring continuous opioid treatment for an extended period of time.

The FDA has approved extended-release (ER) calcifediol (25-hydroxyvitamin D3; Rayaldee – Opko), a prohormone of calcitriol, the active form of vitamin D3. It is indicated for treatment of secondary hyperparathyroidism (SHPT) in adults with stage 3 or 4 chronic kidney disease (CKD) who have serum total 25-hydroxyvitamin D levels <30 ng/mL.

The FDA has approved a combination oral contraceptive containing the estrogen estetrol and the progestin drospirenone (Nextstellis – Mithra/Mayne). Estetrol is the first new estrogen to become available in the US in 50 years. Drospirenone is available alone (Slynd) and in combinations with the estrogen ethinyl estradiol for prevention of pregnancy.

The FDA has approved the oral second-generation antipsychotic drug brexpiprazole (Rexulti – Otsuka/Lundbeck) for once-daily treatment of agitation associated with dementia due to Alzheimer's disease (AD). Brexpiprazole is the first drug to be approved in the US for this indication. It is also approved for treatment of schizophrenia and as an adjunct to antidepressants for treatment of major depressive disorder.

Elafibranor (Iqirvo – Ipsen), a peroxisome proliferator-activated receptor (PPAR) agonist, has been granted accelerated approval by the FDA for treatment of primary biliary cholangitis (PBC) in adults. It is indicated for use in combination with ursodeoxycholic acid (ursodiol, UDCA; Urso, and others) in patients with an inadequate response to UDCA alone and as monotherapy in those unable to tolerate UDCA.