A reader has questioned why the label for the COX-2 selective NSAID celecoxib (Celebrex, and generics), which contains a sulfonamide moiety, states that it is contraindicated for use in patients with an allergy to sulfonamides, while the labels of some other sulfonamide drugs recommend either caution or no precautions at all. The concept of cross-reactivity among sulfonamide drugs, particularly between antibacterial and nonantibacterial sulfonamides, has been controversial for many years.

Dorzolamide hydrochloride (Trusopt - Merck), a thienothio-pyran-2-sulfonamide carbonic anhydrase inhibitor, was recently approved by the US Food and Drug Administration in a 2% ophthalmic solution for treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma.

Zonisamide (Zonegran - Elan Pharma), a sulfonamide chemically unrelated to other antiepileptic drugs, has been approved by the FDA for adjunctive use in adults with partial seizures. Zonisamide has been available in Japan for more than 10 years.

The FDA has approved Simbrinza (Alcon), an ophthalmic combination of the carbonic anhydrase inhibitor brinzolamide and the selective alpha₂-adrenergic receptor agonist brimonidine, for reduction of intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension. Simbrinza is the first product to combine drugs from these 2 classes.

Brinzolamide (Azopt - Alcon), a thieno-thiazine-6-sulfonamide carbonic anhydrase inhibitor, has been approved by the FDA in a 1% ophthalmic suspension for treatment of elevated intraocular pressure due to ocular hypertension or open-angle glaucoma. Brinzolamide is the second FDA-approved topical carbonic anhydrase inhibitor. Dorzolamide (Trusopt) was approved earlier (Medical Letter, 37:76, 1995).

Tipranavir (Aptivus - Boehringer Ingelheim), a new protease inhibitor, has received accelerated approval from the FDA. It must be given with ritonavir (Norvir). The combination is indicated for use with other antiretrovirals to treat HIV infection in highly treatment-experienced adults who have ongoing viral replication or in those with HIV strains known to be resistant to multiple protease inhibitors.

Darunavir (Prezista - Tibotec), a new protease inhibitor, has received accelerated approval from the FDA for use in combination therapy of human-immunodeficiency virus (HIV) infection in previously treated adults. It is coadministered with low-dose ritonavir (Norvir), which increases its bioavailability.

Dichlorphenamide (Keveyis – Taro), an oral carbonic anhydrase inhibitor, has been approved by the FDA for treatment of primary hypokalemic and hyperkalemic periodic paralysis and related variants. Dichlorphenamide is the first drug to be approved in the US for this indication. It was approved as Daranide in 1958 for treatment of glaucoma, but had not been marketed since 2002.

Trimetrexate glucuronate (Parke-Davis), an investigational drug, is now available in the USA from the National Institute of Allergy and Infectious Diseases (NIAID) for treatment of selected AIDS patients with Pneumocystis carinii pneumonia (PCP). For this indication, trimetrexate is always used concurrently with leucovorin (Wellcovorin; and others).

As the weather becomes warmer, physicians may see more photosensitivity reactions due to systemic or topical drugs, perfumes, cosmetics or sunscreens. Even brief exposure to sunlight in warm or cold weather can cause intense cutaneous reactions in patients with drug-induced photosensitivity, and some patients may continue to be sensitive to sunlight long after stopping use of the offending agent.