ATC Class:S01FA02

VA Class:OP600

AHFS Class:

• Mydriatics 52:24

Generic Name(s):

• Scopolamine Hydrobromide

Scopolamine, a naturally occurring tertiary amine antimuscarinic, is a mydriatic and cycloplegic.

Scopolamine hydrobromide is used as a mydriatic and cycloplegic, especially when the patient is sensitive to atropine or when less prolonged cycloplegia is required. The effects of the drug appear more rapidly and have a shorter duration of action than those of atropine. Scopolamine hydrobromide is also used in the management of acute inflammatory conditions (i.e., iridocyclitis) of the iris and uveal tract.

For other uses of scopolamine, see 12:08.08.

Administration

Scopolamine hydrobromide is applied topically to the eye in the form of a solution. To avoid excessive systemic absorption, finger pressure should be applied on the lacrimal sac for 1-2 minutes following topical instillation of the solution. Care should be taken to avoid contamination of the solution container.

Dosage

To produce mydriasis and cycloplegia for refraction in adults, 1 or 2 drops of a 0.25% solution may be instilled onto the eye(s) 1 hour before the procedure; in children, the usual dosage is 1 drop of a 0.25% solution instilled onto the eye(s) twice daily for 2 days before the procedure.

For pupillary dilation in the treatment of acute inflammatory conditions of the iris and uveal tract in adults, 1 or 2 drops of a 0.25% solution may be instilled onto the eye(s) up to 3 times daily; in children, the usual dosage is 1 drop of a 0.25% solution up to 3 times daily.

Adverse Effects

Scopolamine hydrobromide may cause increased intraocular pressure. Prolonged administration of scopolamine hydrobromide to the eye may cause local irritation characterized by follicular conjunctivitis, vascular congestion and edema, exudate, and an eczematoid dermatitis.

Topical application of scopolamine hydrobromide to the eye may cause adverse systemic effects. Following topical application to the eye of several drops of 1% scopolamine hydrobromide, signs and symptoms of confusional psychosis, including restlessness, mental confusion, hallucinations, incoherence, violent behavior, amnesia, unconsciousness, spastic extremities, vomiting, and urinary incontinence, have occurred in several patients. Somnolence has also been reported. Systemic toxicity manifested as systemic antimuscarinic effects has also occurred in a patient following topical application to the eye of a 0.25% solution of the drug every 10 minutes for 2 hours prior to retinal detachment surgery.

For additional information on adverse systemic effects of scopolamine, see Cautions in the Antimuscarinics/Antispasmodics General Statement 12:08.08.

Precautions and Contraindications

Scopolamine hydrobromide ophthalmic solution is contraindicated in patients with known or suspected angle-closure glaucoma. The possibility of undiagnosed glaucoma in geriatric patients should be considered. To avoid induction of angle-closure glaucoma in susceptible patients, an estimation of the depth of the angle of the anterior chamber should be performed prior to initiation of therapy. Scopolamine hydrobromide ophthalmic solution is also contraindicated in patients with known hypersensitivity to the drug or any ingredient in the formulation.

Some commercially available formulations of scopolamine hydrobromide contain sodium metabisulfite, a sulfite that may cause allergic-type reactions, including anaphylaxis and life-threatening or less severe asthmatic episodes, in certain susceptible individuals. The overall prevalence of sulfite sensitivity in the general population is unknown but probably low; such sensitivity appears to occur more frequently in asthmatic than in nonasthmatic individuals.

Pediatric Precautions

Scopolamine hydrobromide should be used with extreme caution, if at all, in infants and small children.

Pharmacology

Scopolamine is a mydriatic and cycloplegic drug which shares the pharmacologic effects of atropine on the eye. Following topical application to the eye, scopolamine blocks the action of acetylcholine resulting in relaxation of the cholinergically innervated sphincter muscle of the iris. Cholinergic stimulation of the accommodative ciliary muscle of the lens is also blocked. Anticholinergic effects of scopolamine in the eye produce dilation of the pupil (mydriasis) and paralysis of accommodation (cycloplegia).

Scopolamine hydrobromide has a more rapid onset of mydriatic and cycloplegic action and less prolonged ocular effects than atropine. The maximum mydriatic effect of scopolamine hydrobromide occurs in about 15-30 minutes following topical application to the eye. Maximum cycloplegia occurs within 30-45 minutes. Mydriasis generally lasts for several days and cycloplegia persists for up to 7 days.

Chemistry and Stability

Chemistry

Scopolamine is a naturally occurring tertiary amine antimuscarinic. Scopolamine is one of the principal antimuscarinic components of the belladonna alkaloids. The drug may be prepared synthetically but is usually obtained by extraction from various members of the Solanaceae genus of plants including Datura matel (datura herb), D. stramonium (Jimson weed), Duboisia myoporoides, Hyoscyamus niger (henbane), and Scopolia carniolica.

Scopolamine is an aminoalcohol ester formed by combining scopine and tropic acid. Scopolamine differs structurally from atropine by the addition of an oxygen bridge between C16 and C17 on the atropine molecule resulting in conversion of tropine to scopine.

Scopolamine hydrobromide is the trihydrate hydrobromide salt of scopolamine. Scopolamine and scopolamine hydrobromide occur as the l -isomer ( l -hyoscine); atroscine ( dl -hyoscine) is the racemic mixture. Scopolamine hydrobromide occurs as colorless or white, odorless crystals or as a white, granular powder which is slightly efflorescent in dry air. Scopolamine hydrobromide has solubilities of approximately 0.67 g/mL in water and 0.05 g/mL in alcohol at 25°C.

Scopolamine hydrobromide ophthalmic solution is a sterile, buffered, aqueous solution of the drug; glacial acetic acid and sodium acetate are added to adjust the pH to 4-6. The ophthalmic solution also contains benzalkonium chloride as a preservative and hydroxypropyl methylcellulose for the purpose of increasing its viscosity.

Stability

Scopolamine is readily racemized in the presence of dilute alkali. Scopolamine hydrobromide solutions are incompatible with alkalies.

Scopolamine hydrobromide ophthalmic solution should be stored in tight containers at a temperature less than 40°C, preferably between 15-30°C; freezing should be avoided.