Phenylephrine/scopolamine ophthalmic Disease Interactions

Anticholinergic agents are contraindicated in patients with primary glaucoma, a tendency toward glaucoma (narrow anterior chamber angle), or adhesions (synechiae) between the iris and lens, as well as for the elderly and others in whom undiagnosed glaucoma or excessive pressure in the eye may be present. Because anticholinergics cause mydriasis, they may exacerbate these conditions.

The use of nonspecific ophthalmic sympathomimetic agents is contraindicated in patients with narrow-angle glaucoma or anatomically narrow angles. These agents stimulate both alpha-1 and alpha-2 adrenergic receptors, thus topical administration can induce transient mydriasis. In patients with narrow angles, pupillary dilation can provoke an acute attack of angle-closure glaucoma. If possible, these agents (except for phenylephrine 2.5% or 10%) should also be avoided in patients with other forms of glaucoma, since mydriasis may occasionally increase intraocular pressure.

Topically applied sympathomimetic agents are systemically absorbed, with the potential for producing clinically significant systemic effects, particularly during prolonged or indiscriminate use. In patients with prostate enlargement, urinary difficulty may develop or worsen due to smooth muscle contraction in the bladder neck via stimulation of alpha-1 adrenergic receptors. Therapy with topical sympathomimetic agents should be administered cautiously in patients with hypertrophy or neoplasm of the prostate. It is important that the recommended dosages of the individual products not be exceeded.

Topically applied sympathomimetic agents are systemically absorbed, with the potential for producing clinically significant systemic effects, particularly during prolonged or indiscriminate use. In cardiac tissues, these agents may produce positive chronotropic and inotropic effects via stimulation of beta-1 adrenergic receptors. Cardiac output, oxygen consumption, and the work of the heart may be increased. In the peripheral vasculature, vasoconstriction may occur via stimulation of alpha-1 adrenergic receptors. Palpitations, tachycardia, arrhythmia, hypertension, reflex bradycardia, and coronary occlusion have been reported rarely during the use of ophthalmic and nasal sympathomimetic agents, but may be more likely if the corneal epithelium is damaged or if an excessive amount of drug is swallowed during nasal administration. Therapy with topical sympathomimetic agents should be administered cautiously in patients with corneal abrasion, sensitivity to sympathomimetic amines, hyperthyroidism, or underlying cardiovascular or cerebrovascular disorders, especially coronary insufficiency, cardiac arrhythmia, or hypertension. The potent ophthalmic formulations (e.g., phenylephrine 2.5% or 10%) that are used for diagnostic and pre-surgical purposes should not be used in such patients. For other preparations, it is important that the recommended dosages of the individual products not be exceeded.

Topically applied sympathomimetic agents are systemically absorbed, particularly during prolonged or indiscriminate use. Slight increases in blood glucose concentrations may occur with the use of these drugs. Therapy with topical sympathomimetic agents should be administered cautiously in patients with diabetes mellitus. Closer monitoring of blood glucose concentrations may be appropriate. It is important that the recommended dosages of the individual products not be exceeded.