ZONEGRAN® (zonisamide) is an antiseizure drug chemically classified as a sulfonamide and unrelated to other antiseizure agents. The active ingredient is zonisamide, 1,2-benzisoxazole-3-methanesulfonamide. The empirical formula is C₈H₈N₂O₃ with a molecular weight of 212.23. Zonisamide is a white powder, pKa = 10.2, and is moderately soluble in water (0.80 mg/mL) and 0.1 N HC1 (0.50 mg/mL).

Zolpimist contains zolpidem tartrate, a non-benzodiazepine hypnotic of the imidazopyridine class. Chemically, zolpidem is N,N,6-trimethyl-2-p-tolylimidazo[1,2-a] pyridine-3-acetamide L-(+)tartrate (2:1). It has the following structure:

HIVID is the Hoffmann-La Roche brand of zalcitabine [formerly called 2',3'-dideoxycytidine (ddC)], a synthetic pyrimidine nucleoside analogue active against the human immunodeficiency virus (HIV). HIVID (zalcitabine) is available as film-coated tablets for oral administration in strengths of 0.375 mg and 0.750 mg. Each tablet also contains the inactive ingredients lactose, microcrystalline cellulose, croscarmellose sodium, magnesium stearate, hydroxypropyl methylcellulose, polyethylene glycol, and polysorbate 80 along with the following colorant system: 0.375 mg tablet — synthetic brown, black, red and yellow iron oxides, and titanium dioxide; 0.750 mg tablet — synthetic black iron oxide and titanium dioxide. The chemical name for zalcitabine is 4-amino-1-beta-D-2', 3'-dideoxyribofuranosyl-2-(1H)-pyrimidone or 2',3'-dideoxycytidine with the molecular formula C₉H₁₃N₃O₃ and a molecular weight of 211.22. Zalcitabine has the following structural formula:

ZYVOX I.V. Injection, ZYVOX Tablets, and ZYVOX for Oral Suspension contain linezolid, which is a synthetic antibacterial agent of the oxazolidinone class. The chemical name for linezolid is (S)-N-[[3-[3-Fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl] methyl]-acetamide.

Zometa contains zoledronic acid, a bisphosphonic acid which is an inhibitor of osteoelastic bone resorption. Zoledronic acid is designated chemically as (l-Hydroxy-2-imidazol-l-yl-phosphonoethyl) phosphonic acid monohydrate and its structural formula is

The active ingredient in ZANTAC Injection and ZANTAC Injection Premixed is ranitidine hydrochloride (HCl), a histamine H2-receptor antagonist. Chemically it is N[2-[[[5-[(dimethylamino)methyl]-2-furanyl]methyl]thio]ethyl]-N'-methyl-2-nitro-1,1-ethenediamine, hydrochloride. It has the following structure:

Zileuton is an orally active inhibitor of 5-lipoxygenase, the enzyme that catalyzes the formation of leukotrienes from arachidonic acid. Zileuton has the chemical name (±)-1-(1-Benzo[b]thien-2-ylethyl)-1-hydroxyurea and the following chemical structure:

Intermezzo contains zolpidem tartrate, a non-benzodiazepine hypnotic of the imidazopyridine class. Intermezzo is available in 1.75 mg and 3.5 mg strength tablets for sublingual administration. Intermezzo sublingual tablets are intended to be placed under the tongue where they will disintegrate.

ZYLOPRIM (allopurinol) has the following structural formula:

Zarontin (ethosuximide) is an anticonvulsant succinimide, chemically designated as alpha-ethyl-alpha-methyl-succinimide, with the following structural formula: