The present invention relates to compositions comprising a 4-nitrooxybutan-1-ol alkyl ester as nitric oxide donor. More specifically, the invention relates to compositions comprising 4-nitrooxybutan-1-ol alkyl ester as a nitric oxide donor and an ophthalmic drug, useful in controlling elevated intraocular pressure associated with glaucoma or ocular hypertension associated with other diseases or conditions. The invention is also directed to methods of controlling intraocular pressure utilizing said compositions.
