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TRANSDERM-V® Novartis Pharmaceuticals Scopolamine Anti-Motion Sickness Agent
 
Action and Clinical

Scopolamine is a naturally occurring belladonna alkaloid. As a parasympatholytic agent it competitively antagonizes acetylcholine (or other direct parasympathomimetics) at the muscarinic receptor. This means that its effect can be abolished by high doses of a parasympathomimetic agent. The effect of scopolamine depends on the sensitivity of the target organs and on the size of the dose employed.:

The principal actions of scopolamine are related to anticholinergic effects which include depressed motor function, decreased salivation and sweating, mydriasis, inhibition of visual accommodation, and tachycardia. Drowsiness may also occur at therapeutic doses.

The mechanism of action of scopolamine in the CNS is not well known but may include anticholinergic effects. The ability of scopolamine to prevent motion-induced nausea is believed to be associated with inhibition of vestibular input to the CNS, which results in inhibition of the vomiting reflex. In addition, scopolamine may have a direct action on the vomiting centre within the reticular formation of the brain stem.

After transdermal administration of scopolamine, the time necessary to reach maximum blood levels (estimated by urinary excretion of scopolamine) is approximately 12 hours. The disc is designed for continuous release of scopolamine over the 3 day functional lifetime. Scopolamine excretion continues for up to 12 hours after removal of the system. Approximately 5 to 8% of the administered drug is excreted unchanged.

Indications And Clinical Uses:

For prevention of symptoms of motion sickness such as nausea and vomiting.

Contra-Indications:

Known hypersensitivity to scopolamine or any components of the system.

Glaucoma or a predisposition to angle-closure glaucoma (see Warnings).

Warnings in Clinical States:

Occupational Hazards: Since drowsiness, disorientation and confusion may occasionally occur with the use of scopolamine, patients should be cautioned about engaging in activities that require mental alertness, such as driving a motor vehicle or operating dangerous machinery.

Potentially alarming idiosyncratic reactions may occur with ordinary therapeutic doses of scopolamine.

In patients with a history of possible raised intraocular pressure (pressure pain, blurred vision, glaucomatous halo), scopolamine should be employed only after ophthalmological examination excludes glaucoma (see Contraindications).

Scopolamine should be discontinued if it causes blurring of vision with pressure pain within the eye (see Contraindications).

Precautions:

Scopolamine should be used with caution in patients with dysuria, e.g., due to urinary bladder neck obstruction. Caution should be exercised when administering an antiemetic or antimuscarinic drug to patients suspected of having intestinal obstruction, e.g., pyloric stenosis.:

Scopolamine should be used with caution in the elderly or in individuals with impaired metabolic, liver or kidney functions.

In certain cases, especially in the elderly, confusional states and/or visual hallucinations may occur. Should this occur, scopolamine should be removed at once. If severe symptoms persist, appropriate countermeasures should be taken (see Overdose: Symptoms and Treatment).

In epileptic patients, isolated cases of increased seizure frequency have been reported.

Children: Children are particularly susceptible to the side effects of belladonna alkaloids. Transderm-V should not be used in children because it is not known whether the amount of scopolamine released could produce serious adverse effects in children.

Pregnancy: Scopolamine should be used during pregnancy only if the anticipated benefit justifies the potential risk to the mother and fetus.

Lactation: Scopolamine should not be administered to nursing mothers since it is excreted into breast milk.

Drug Interactions :

Scopolamine should be employed with caution in patients taking drugs which act on the CNS. This applies particularly to patients under treatment with drugs displaying anticholinergic properties, for example, belladonna alkaloids, antihistamines, antidepressants (tricyclics and MAO inhibitors), phenothiazines, amantadine and quinidine.

Any parasympatholytic or sympathomimetic agent or barbiturate should be administered with caution to persons wearing scopolamine.

Patients should refrain from consuming alcohol while using scopolamine. Alcohol may interfere with the metabolism of the drug and could thus cause plasma levels to become elevated, which could intensify the side effects.

Information for the Patient: Since scopolamine can cause temporary dilation of the pupils and blurred vision if it comes in contact with the eyes, patients should be strongly advised to wash their hands thoroughly with soap and water immediately after handling the disc and to avoid touching the disc while in place behind the ear.

Patients should be advised to remove the disc and contact a physician promptly in the unlikely event that they experience symptoms of angle-closure glaucoma (pain in and reddening of the eyes accompanied by dilated pupils).

Patients should be instructed to remove the disc if they develop difficulty urinating.

Patients should be advised to refrain from consuming alcohol while using scopolamine.

Patients should be warned against driving a motor vehicle or operating dangerous machinery.

Adverse Reactions:

A patient leaflet is supplied with the discs.

Gastrointestinal: Frequent: transient dryness of the mouth.

Ophthalmic: Frequent: transient impairment of eye accommodation (cycloplegia), including blurred (near) vision and dilatation of the pupils (sometimes in one eye only), especially if traces of active substance on the hands enter the eyes. Occasional: irritation of the eyelids. Isolated cases: dilatation of the pupils may provoke acute glaucoma, especially angle-closure glaucoma.

CNS: Occasional: drowsiness. Rare: impairment of memory and concentration, restlessness, giddiness, dizziness, disorientation, confusion and hallucinations.

Dermatological: Occasional: local irritation of the skin. Isolated cases: generalized skin rash.

Genitourinary: Rare: disturbances of micturition (retention of urine).

Cardiovascular: Isolated cases: slight variations in blood pressure.

Adverse Effects after Withdrawal of Scopolamine: In certain instances, there have been complaints of transient dizziness, nausea, vomiting, headache and disturbances of balance following discontinuation of scopolamine, usually after several days of use.

Symptoms And Treatment Of Overdose :

OverdoseSymptoms: The central actions of scopolamine in high doses are similar to those of atropine. They begin with restlessness, excitation states, disorientation and confusion. In response to higher doses, delirium, hallucinations and convulsions set in. At very high doses coma and respiratory paralysis occur.Treatment

Treatment: Remove the disc immediately.

Treatment of acute antimuscarinic overdose consists mainly of symptomatic and supportive treatments. Patients should be hospitalized and closely monitored, including continuous ECG monitoring.

The most effective antidote is physostigmine, which, depending on the severity of the poisoning, should be injected slowly i.v. in doses of 1 to 4 mg (0.5 mg in children). Since physostigmine is rapidly metabolized, the patients may lapse into coma again within 1 to 2 hours, thus necessitating renewed injections. It should, however, be noted that physostigmine has the potential for producing severe adverse effects (for instance, seizures, asystole). The use of physostigmine should, therefore, be reserved for life-threatening situations only.

Fairly small doses of diazepam may prove useful in the presence of excitation states and convulsions. Larger doses should be avoided in view of the possibility of additional respiratory depression. In severe cases artificial respiration may be necessary.

In the event of hyperthermia, urgent action should be taken to dissipate heat (e.g., cold baths).

Dosage And Administration:

Adults: To obtain optimum effect, Transderm-V should be applied to a dry, hairless area of post-auricular skin approximately 12 hours before the antiemetic effect is required. Only 1 disc should be worn at any time. Should the disc become displaced, it should be discarded and a fresh one placed on a different skin site.

Scopolamine provides protection over a 3 day period. If the disc is only needed for a shorter time, it should be removed at the end of the journey.

If therapy is required for longer periods, the first disc should be removed after 72 hours and a second disc applied behind the other ear.

Children: Scopolamine should not be used in children (see Precautions).

Transderm-V is designed to deliver in vitro 1 mg scopolamine at a constant rate over the 3 day functional lifetime. An initial priming dose of scopolamine, released from the adhesive layer of the system, saturates the skin binding sites for the drug and brings the plasma concentration to the required steady state level. Subsequently, there is continuous controlled release of scopolamine, from the drug reservoir through the rate-controlling membrane.

Handling: After the disc is applied on dry skin behind the ear, the hands should be washed thoroughly with soap and water, then dried. Once the disc has been affixed, it should not be touched again while it is being worn. Upon removal, the disc should be carefully discarded, and the hands and application site washed thoroughly with soap and water to prevent traces of scopolamine from coming in direct contact with the eyes. If scopolamine were to contact the eyes it could cause slight temporary blurring of vision and dilation of the pupils (sometimes in one eye only).

Availability And Storage:

Each flat, circular, multilayer, tan-colored, adhesive disc (contact surface 2.5 cm

Transderm-V is a 0.2 mm-thick film with 5 layers. Proceeding from the visible surface towards the surface attached to the skin, these layers are: (1) a backing layer of tan-colored, aluminized polyester film; (2) a drug reservoir of scopolamine, mineral oil and polyisobutylene; (3) a microporous polypropylene membrane that controls the rate of delivery of scopolamine from the system to the skin surface; (4) an adhesive formulation of mineral oil, polyisobutylene and a priming dose of scopolamine; (5) a clear hexagonal protective liner (peel strip) of siliconized polyester, which is removed before applying the disc.

Store below 25°C. Do not freeze. Each disc is individually sealed in a separate pouch. Do not store out of the pouch. Apply immediately upon removal from the protective pouch. Keep out of the reach of children and pets both before use and when disposing of used discs.