Sirolimus, whlch is structurally related to tacrolimus, has been approved by the FDA for prevention of acute renal transplant rejection. The manufacturer recommends that sirolimus be taken with cyclosporine and corticosteroids.

Mycophenolate mofetil (CellCept - Roche) has been approved by the US Food and Drug Administration for oral use in preventing organ rejection in patients receiving allogeneic renal transplants. It is being promoted as an improvement over azathioprine (Imuran) for concurrent use with cyclosporine (Sandimmune; Neoral) and corticosteroids.

Basiliximab (Simulect - Novartis) and daclizumab (Zenapax - Roche), two mouse/human monoclonal antibodies that block the interleukin-2 (IL-2) receptor on Tlymphocytes, have been approved by the FDA for use in the prevention of acute renal transplant rejection. Both drugs are used with cyclosporine (Sandimmune; Neoral) and corticosteroids. An all-murine anti-CD3 monoclonal antibody, muromonab-CD3 (Orthoclone OKT3), has been available in the USA for many years for treatment of transplant rejection, and has also been used with some success for prophylaxis (MI Wilde and KL Goa, Drugs,...

The FDA has approved deucravacitinib (Sotyktu – BMS), an oral tyrosine kinase 2 (TYK2) inhibitor, for once-daily treatment of moderate to severe plaque psoriasis in adults who are candidates for systemic therapy or phototherapy. Deucravacitinib is the first selective TYK2 inhibitor to be approved in the US for any indication.

The US Food and Drug Administration (FDA) has approved two new retinoids for treatment of psoriasis. Tazarotene gel 0.05% and 0.1% (Tazorac - Allergan) is being marketed for topical use in patients with stable, mild to moderate plaque psoriasis. Acitretin (Soriatane - Roche) is being promoted for systemic use in severe psoriasis.

Changes caused by one drug in the absorption, distribution, metabolism or excretion of another may lead to a pharmacokinetic adverse drug interaction (DN Juurlink et al, JAMA 2003; 289:1652). Additive drug interactions, such as vasodilation caused by both sildenafil (Viagra) and nitrates, can also have adverse effects.

In a study of the interaction between alcohol and the calcium-channel blocker felodipine (Plendil), the grapefruit juice vehicle for the alcohol appeared to increase felodipine plasma concentrations. Subsequent studies have found that grapefruit juice increases plasma concentrations of several calcium-channel blockers and of some other drugs as well (DG Bailey et al, Clin Pharmacokinet, 26:91, 1994).

Alefacept (a le' fa sept; Amevive - Biogen) has been approved by the FDA for parenteral treatment of adults with moderate to severe chronic plaque psoriasis.

Serious adverse interactions between drugs continue to be reported. Many of these are due to inhibition or induction of cytochrome P450 (CYP) enzymes, particularly CYP3A4. CYP3A is thought to be involved in the metabolism of more than 50 percent of currently prescribed drugs.2 CYP3A4, which is more abundantly expressed than CYP3A5, accounts for most CYP3A activity in vivo.

The FDA has approved the use of aliskiren (Tekturna), a direct renin inhibitor, with valsartan (Diovan), an angiotensin-receptor blocker (ARB), in a fixed-dose combination as Valturna (Novartis) for treatment of hypertension in patients already taking both drugs or not adequately controlled on monotherapy, and as initial therapy in those likely to need multiple drugs to control their blood pressure.