Xylocaine (lidocaine HCl) Injections are sterile, nonpyrogenic, aqueous solutions that contain a local anesthetic agent with or without epinephrine and are administered parenterally by injection.

XERESE (acyclovir and hydrocortisone cream) contains acyclovir, a synthetic nucleoside analogue active against herpes viruses, and hydrocortisone, an anti-inflammatory corticosteroid, combined in a cream for topical administration. Each gram of XERESE (acyclovir and hydrocortisone cream) contains 5% (w/w) of acyclovir, 1% (w/w) of hydrocortisone and the following inactive ingredients: cetostearyl alcohol, mineral oil, Poloxamer 188, propylene glycol, isopropyl myristate, sodium lauryl sulfate, white petrolatum, citric acid, sodium hydroxide and water. Sodium hydroxide or hydrochloric acid may be added to adjust the pH to approximately pH 5.

XANAX XR Tablets contain alprazolam which is a triazolo analog of the 1,4 benzodiazepine class of central nervous system-active compounds.

Xolair (Omalizumab) is a recombinant DNA-derived humanized IgG1? monoclonal antibody that selectively binds to human immunoglobulin E (IgE). The antibody has a molecular weight of approximately 149 kilodaltons. Xolair (omalizumab) is produced by a Chinese hamster ovary cell suspension culture in a nutrient medium containing the antibiotic gentamicin. Gentamicin is not detectable in the final product.

Xenon Xe 133 Gas is supplied in a mixture of xenon gas (5%) in carbon dioxide (95%). It is contained within septum sealed glass vials and is suitable for inhalation in the diagnostic evaluation of pulmonary function and imaging, as well as assessment of cerebral blood flow. Xenon Xe 133 Gas is reactor-produced as a by-product of Uranium U235 fission. Each vial contains the labeled amount of Xenon Xe 133 radioactivity at the time of calibration. The contents of the vial are in gaseous form, contain no preservatives, and are ready for use.

XALKORI (crizotinib) is an oral receptor tyrosine kinase inhibitor. The molecular formula for crizotinib is C₂₁H₂₂Cl₂FN₅O. The molecular weight is 450.34 Daltons. Crizotinib is described chemically as (R)-3-[l-(2,6-Dichloro-3 -fluorophenyl)ethoxy] -5- [1-(piperidin-4-yl)- 1H-pyrazol-4-yl]pyridin-2-amine.

Xyrem (sodium oxybate) is a central nervous system depressant that reduces excessive daytime sleepiness and cataplexy in patients with narcolepsy. Sodium oxybate is intended for oral administration. The chemical name for sodium oxybate is sodium 4-hydroxybutyrate. The molecular formula is C₄H₇NaO₃ and the molecular weight is 126.09 grams/mole. The chemical structure is:

The active component of XOPENEX HFA (levalbuterol tartrate) Inhalation Aerosol is levalbuterol tartrate, the (R)-enantiomer of albuterol. Levalbuterol tartrate is a relatively selective beta2-adrenergic receptor agonist (see CLINICAL PHARMACOLOGY). Levalbuterol tartrate has the chemical name (R)-?1-[[(1,1-dimethylethyl)amino]methyl]- 4-hydroxy-1,3-benzenedimethanol L-tartrate (2:1 salt), and it has the following chemical structure: