SCOPOLAMINE

SCOPOLAMINE
(skoe-pol'a-meen)
Transderm Scop, Transderm-V

SCOPOLAMINE HYDROBROMIDE
Hyoscine, Isopto-Hyoscine, Scopace, Murocoll, Triptone
Classifications: anticholinergic; antimuscarinic; antispasmodic; antivertigo;
Therapeutic: antispasmodic; antiemetic; antivertigo
Prototype: Atropine
Pregnancy Category: C

Availability

Scopolamine: 1.5 mg transdermal patch;

Scopolamine HBr: 0.4 mg tablets; 0.3 mg/mL, 0.4 mg/mL, 0.86 mg/mL, 1 mg/mL injection; 0.25% ophthalmic solution

Action

Antimuscarinic agent that inhibits the action on acetylcholine (ACh) on postganglionic cholinergic nerves as well as on smooth muscles that lack cholinergic innervation.

Therapeutic Effect

More potent than atropine in mydriatic and cycloplegic effects. Produces CNS depression with marked sedative and tranquilizing effects for use in anesthesia. Effective as a preanesthetic agent to control bronchial, nasal, pharyngeal, and salivary secretions.

Uses

In obstetrics with morphine to produce amnesia and sedation ("twilight sleep") and as preanesthetic medication. To control spasticity (and drooling) in postencephalitic parkinsonism, paralysis agitans, and other spastic states, as prophylactic agent for motion sickness and as mydriatic and cycloplegic in ophthalmology. Therapeutic system (Transderm Scop) is used to prevent nausea and vomiting associated with motion sickness.

Contraindications

Hypersensitivity to anticholinergic drugs; hypersensitive to belladonna or barbiturates; asthma; hepatitis; narrow-angle glaucoma; GI or urogenital obstructive diseases; myasthenia gravis; pregnancy (category C); toxemia of pregnancy.

Cautious Use

Coronary heart disease, CHF, cardiac arrhythmias, tachycardia, hypertension; infants, children, Down's syndrome; patients >40 y, pyloric obstruction, urinary bladder neck obstruction; autonomic neuropathy; angle-closure glaucoma, thyrotoxicosis, liver disease; paralytic ileus; hiatal hernia, ulcerative colitis, gastric ulcer; older adults, parkinsonism; COPD, asthma or allergies; hyperthyroidism; brain damage, spastic paralysis; tartrazine or sulfite sensitivity.

Route & Dosage

Preanesthetic
Adult: PO 0.4–0.8 mg IM/SC/IV 0.3–0.6 mg q4–6h
Child: PO/IM/SC/IV 6 mcg/kg q6–8h (max: 0.3 mg/dose)

Motion Sickness
Adult: Topical 1 patch q72h starting 12 h before anticipated travel
Child: PO 6 mcg/kg 1 h before anticipated travel

Refraction
Adult: Ophthalmic 1–2 drops in eye 1 h before refraction

Uveitis
Adult: Ophthalmic 1–2 drops in eye up to q.i.d.

Administration

Instillation

Minimize possibility of systemic absorption by applying pressure against lacrimal sac during and for 1 or 2 min following instillation of eye drops.

Transdermal

Apply transdermal disc system (Transderm Scop, a controlled-release system) to dry surface behind the ear.
Replace with another disc on another site behind the ear if disc system becomes dislodged.

Subcutaneous or/Intramuscular

Give undiluted.

Intravenous

PREPARE: Direct: Dilute required dose with an equal volume of sterile water for injection.

ADMINISTER: Direct: Give a single dose slowly over 2–3 min.

Preserve in tight, light-resistant containers.

Adverse Effects (≥1%)

Body as a Whole: Fatigue, dizziness, drowsiness, disorientation, restlessness, hallucinations, toxic psychosis. GI: Dry mouth and throat, constipation. Urogenital: Urinary retention. CV: Decreased heart rate. Special Senses: Dilated pupils, photophobia, blurred vision, local irritation, follicular conjunctivitis. Respiratory: Depressed respiration. Skin: Local irritation from patch adhesive, rash.

Interactions

Drug: Amantadine, antihistamines, tricyclic antidepressants, quinidine, disopyramide, procainamide add to anticholinergic effects; decreases levodopa effects; methotrimeprazine may precipitate extrapyramidal effects; decreases antipsychotic effects (decreased absorption) of phenothiazines. Food: Grapefruit juice (>1 qt/d) may increase plasma concentrations and adverse effects.

Pharmacokinetics

Absorption: Readily from GI tract and percutaneously. Peak: 20–60 min. Duration: 5–7 d. Distribution: Crosses placenta; distributed to CNS. Metabolism: In liver. Elimination: In urine.

Nursing Implications

Assessment & Drug Effects

Observe patient closely; some patients manifest excitement, delirium, and disorientation shortly after drug is administered until sedative effect takes hold.
Use of side rails is advisable, particularly for older adults, because of amnesic effect of scopolamine.
In the presence of pain, scopolamine may cause delirium, restlessness, and excitement unless given with an analgesic.
Be aware that tolerance may develop with prolonged use.
Terminate ophthalmic use if local irritation, edema, or conjunctivitis occur.

Patient & Family Education

Vision may blur when used as mydriatic or cycloplegic; do not drive or engage in potentially hazardous activities until vision clears.
Place disc on skin site the night before an expected trip or anticipated motion for best therapeutic effect.
Wash hands carefully after handling scopolamine. Anisocoria (unequal size of pupils, blurred vision can develop by rubbing eye with drug-contaminated finger).

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

(226)