Scopolamine Patch

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Definition

A scopolamine patch (Transdermal Scop or Transderm-V) is an adhesive medication patch that is applied to the skin behind the ear. The patch is treated with the belladonna alkaloid scopolamine, an anticholinergic drug that is a central nervous system depressant and an antiemetic.

Purpose

Scopolamine patches are prescribed to reduce postoperative nausea and vomiting (PONV) associated with anesthesia and surgery. Scopolamine also has a mild analgesic and sedative effect, which adds to its therapeutic value for some surgical patients. In addition to PONV, scopolamine patches are also used for the treatment of motion sickness.

Demographics

Elderly patients may be more sensitive to scopolamine treatment and its use should be prescribed with caution in this group. The safety of scopolamine patches has not been determined in children; therefore the drug's use in pediatric patients is not recommended.

Description

A potent drug derived from an alkaloid of belladonna (Atropa belladonna; common name deadly nightshade), scopolamine works by depressing the action of the nerve fibers near the ear and the vomiting center of the brain and central nervous system (CNS). The patch itself is designed with special layered materials that slowly release a small dose of the drug transdermally (through the skin) over a period of several days.

Patients who are instructed to apply their patch at home should wash their hands thoroughly both before and after the procedure. Scopolamine can be spread to the eyes by hand, which can cause blurred vision and pupil dilation. Patches should never be cut into pieces, as cutting destroys the time-release mechanism of the drug. The directions for use for the patch should be read thoroughly before application, and specific physician instructions should also be followed. The drug will start to work approximately four hours after the patch is applied.

Diagnosis/Preparation

The dime-sized scopolamine patch is applied just behind either the left or right ear. The area should be clean and hairless prior to the application, which should occur the evening before a scheduled surgery. For women who are prescribed a scopolamine patch to reduce nausea and vomiting related to a cesarean section, the patch should be applied just one hour before the procedure to minimize the baby's exposure to the drug. Scopolamine does cross the placental barrier, but as of early 2003, clinical studies have not shown any negative affects on newborn babies of mothers who used the drug in a caesarean delivery.

Patients with a history of glaucoma, prostate enlargement, kidney or liver problems, bladder obstruction, gastrointestinal obstruction, or contact dermatitis (allergic skin rash) in response to topical drugs may not be suitable candidates for scopolamine patch therapy. A physician or anesthesiologist should take a full medical history before prescribing scopolamine to determine if the medication is appropriate.

Aftercare

Patients who receive a scopolamine patch should not drive or operate heavy machinery until the therapy is complete. Patch therapy generally lasts about three days. Patches should be disposed of according to the manufacturer's directions in a secure place to ensure that small children or pets do not get access to them. If PONV has not resolved after patch therapy has ended, patients should talk to their doctor about their treatment options.

Risks

Possible complications or side effects from transdermal scopolamine include but are not limited to: short-term memory loss, fatigue, confusion, hallucinations, difficulty urinating, and changes in heart rate. The drug can trigger seizures and psychotic delusions in patients with a history of these problems. Dizziness, nausea, headache, and hypotension (low blood pressure) have also been reported in some patients upon discontinuation of scopolamine patch therapy.

Patients who experience eye pain with redness and possible blurred vision should remove the patch immediately and call their doctor, since these symptoms could be signs of a rare but possible side effect of scopolamine called narrow-angle glaucoma. Blurriness with or without pupil dilation is also a potential but generally harmless side effect of the drug.

Normal Results

When scopolamine patch therapy works, it reduces or eliminates post-surgical nausea and vomiting. Patients frequently experience dry mouth as a common side effect of the drug.

Alternatives

Intravenous or intramuscular injection of scopolamine may be used as alternatives to patch therapy for some patients. Other antiemetics that may be prescribed for PONV include anti-droperidol drugs, dopaminergic drugs (i.e., promethazine, droperidol), antihistamines (i.e., diphenhydramine), and the serotonin receptor antagonists (i.e., ondansetron, granisetron, tropisetron, dolasetron). Corticosteroids may also be recommended for PONV in some patients.

Resources

Books

Litwack, Kim, ed. Core Curriculum for Perianesthesia NursingPractice, 4th edition. Philadelphia: W.B. Saunders, 1999.

Periodicals

Gan, T. J. "Postoperative nausea and vomiting—can it be eliminated?" Journal of the American Medical Association 287 (March 13, 2002): 1233–6.

— Paula Ford-Martin