hyoscyamine (redirected from Levsin)

hyoscyamine /hyo·scy·amine/ (hi?o-si´ah-men) an anticholinergic alkaloid that is the levorotatory component of racemic atropine and has similar actions but twice the potency; used as an antispasmodic in gastrointestinal and urinary tract disorders, as the base or hydrobromide or sulfate salt.

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hy·o·scy·a·mine (h-s-mn)

n.

A poisonous white crystalline alkaloid isometric with atropine and having similar uses but more potent effects.

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hyoscyamine

an anticholinergic alkaloid usually obtained from species of the plant Hyoscyamus and other solanaceous plants. It is the levorotatory component of atropine with actions and uses similar to those of atropine but with more potent effects.

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hyoscyamine

Cystospaz, Hyospaz

Pharmacologic class: Anticholinergic

Therapeutic class: Antispasmodic

Pregnancy risk category C

Action

Competitively inhibits acetylcholine action at autonomic nerve sites, relaxing smooth muscle and decreasing glandular secretions

Availability

hyoscyamine

Tablets: 0.15 mg

hyoscyamine sulfate

Capsules (timed-release): 0.375 mg

Elixir: 0.125 mg/5 ml

Injection: 0.5 mg/ml

Oral solution: 0.125 mg/ml

Tablets: 0.125 mg

Tablets (extended-release): 0.375 mg

Tablets (orally disintegrating): 0.125 mg

Tablets (sublingual): 0.125 mg

⊘Indications and dosages

➣ Adjunct in GI tract disorders; pain and hypersecretion in pancreatitis; cystitis; renal colic; infant colic; acute rhinitis; rigidity, tremors, and hyperhidrosis in Parkinson's disease; partial heart block due to vagal activity

Adults: 0.15 to 0.3 mg P.O. up to q.i.d.

Adults and children ages 12 and older: 0.125 to 0.25 mg (sulfate) P.O. or S.L. two to four times daily, or 0.375 to 0.75 mg (extended-release sulfate) P.O. q 12 hours, or 0.25 to 0.5 mg (sulfate) subcutaneously, I.M., or I.V. two to four times daily p.r.n.

Children ages 2 to 12: In children weighing approximately 50 kg (110 lb), 0.125 mg (sulfate) P.O. q 4 hours p.r.n.; in children weighing approximately 20 kg (40 lb), 0.0625 mg P.O. (sulfate); in children weighing approximately 10 kg (22 lb), 0.031 to 0.033 mg (sulfate) P.O. Don't exceed 0.75 mg/day.

Children ages 2 and younger: In children weighing approximately 7 kg (15 lb), 0.025 (sulfate) P.O. q 4 hours p.r.n.; in children weighing approximately 5 kg (11 lb), 0.0208 mg (sulfate) P.O. q 4 hours p.r.n.; in children weighing approximately 3.4 kg (7.5 lb), 0.0167 mg (sulfate) P.O. q 4 hours p.r.n.; in children weighing approximately 2.3 kg (5 lb), 0.0125 mg (sulfate) P.O. q 4 hours p.r.n.

➣ Before endoscopy or hypotonic duodenography

Adults: 0.25 to 0.5 mg (sulfate) subcutaneously, I.M., or I.V. 5 to 10 minutes before procedure

➣ Preoperatively to inhibit salivation and excessive respiratory secretions

Adults and children older than age 2: 5 mcg/kg (sulfate) I.M., I.V., or subcutaneously 30 to 60 minutes before anesthesia induction

➣ Muscarinic toxicity

Adults: 1 to 2 mg (sulfate) I.V. Additional 1-mg doses may be given I.M. or I.V. q 3 to 10 minutes until muscarinic signs and symptoms subside; doses may be repeated if needed. Patient may need up to 25 mg during first 24 hours. For maintenance, 0.5 to 1 mg P.O. at intervals of several hours until signs and symptoms disappear.

Contraindications

• Hypersensitivity to anticholinergics, alcohol, sulfites, or tartrazine
• Angle-closure glaucoma, synechia
• GU or GI obstructive disease, severe ulcerative colitis
• Renal or hepatic disease
• Neonates or premature infants

Precautions

Use cautiously in:
• cardiovascular disease, prostatic hypertrophy, reflux esophagitis, brain damage, autonomic neuropathy, hyperthyroidism, glaucoma, Down syndrome, spastic paralysis
• elderly patients
• pregnant (safety not established) or breastfeeding patients
• infants and small children.

Administration

• Administer 30 to 60 minutes before meals and at bedtime.
• Give bedtime dose at least 2 hours after last evening meal or snack.
• Be aware that hyoscyamine is given P.O. only, whereas hyoscyamine sulfate may be given P.O., I.M., I.V., sublingually, or subcutaneously.
• Know that a cholinerase reactivator (pralidoxime) is given concomitantly to treat muscarinic toxicity.

Route	Onset	Peak	Duration
P.O.	20-30 min	0.5-1 hr	4-12 hr
P.O. (extended)	20-30 min	40-90 min	12 hr
I.V.	2 min	15-30 min	4 hr
I.M., subcut.	Unknown	15-30 min	4-12 hr
S.L.	5-20 min	0.5-1 hr	4 hr

Adverse reactions

CNS: confusion, excitement, nervousness, dizziness, light-headedness, headache, insomnia

CV: palpitations, tachycardia

EENT: blurred vision, cycloplegia, increased intraocular pressure, mydriasis, photophobia

GI: nausea, vomiting, constipation, bloating, dry mouth, paralytic ileus

GU: urinary hesitancy or retention, erectile dysfunction, lactation suppression

Skin: flushing, decreased sweating, urticaria, local irritation (with I.M., I.V., or subcutaneous use)

Other: altered taste, allergic reactions (including fever), heat intolerance, anaphylaxis

Interactions

Drug-drug. Amantadine, antihistamines, antiparkinsonian drugs, disopyramide, glutethimide, meperidine, procainamide, quinidine, tricyclic antidepressants: increased anticholinergic effects

Antacids: decreased hyoscyamine absorption

Atenolol: increased atenolol effects

Ketoconazole: interference with absorption of both drugs

Methotrimeprazine: increased risk of extrapyramidal effects

Phenothiazines: decreased phenothiazine effects, increased anticholinergic effects

Drug-herbs. Jimsonweed: adverse cardiovascular effects

Patient monitoring

• Watch for adverse reactions.
• Check for mental status changes, such as confusion.
• Evaluate fluid intake and output.
• Assess patient's response to temperature changes (especially hot weather). Drug may cause heat intolerance, predisposing patient to heat stroke.

Patient teaching

• Tell patient to take on empty stomach 30 to 60 minutes before meals and at least 2 hours after last evening meal or snack.
• Instruct patient with urinary hesitancy to empty bladder before taking.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and herbs mentioned above.