Action And Clinical Pharmacology: Hyoscyamine inhibits specifically the actions of acetylcholine on structures innervated by postganglionic cholinergic nerves and on smooth muscles that respond to acetylcholine but lack cholinergic innervation. These peripheral cholinergic receptors are present in the autonomic effector cells of the smooth muscle, cardiac muscle, the sinoatrial node, the atrioventricular node, and the exocrine glands. It is completely devoid of any action in the autonomic ganglia. Hyoscyamine inhibits gastrointestinal propulsive motility and decreases gastric acid secretion. Hyoscyamine also controls excessive pharyngeal, tracheal, and bronchial secretions.
Hyoscyamine is absorbed totally and completely by sublingual administration as well as oral administration. Once absorbed, hyoscyamine disappears rapidly from the blood and is distributed throughout the entire body. The half-life of hyoscyamine is 3.5 hours and the majority of drug is excreted in the urine unchanged within the first 12 hours. Only traces of this drug are found in breast milk. Hyoscyamine passes the blood brain barrier and placenta barrier.
Indications And Clinical Uses: Adjunct therapy in the treatment of peptic ulcer. To control gastric secretion, visceral spasm and hypermotility in spastic colitis, spastic bladder, cystitis, pylorospasm, and associated abdominal cramps. Used in functional intestinal disorders to reduce symptoms such as those seen in mild dysenteries, diverticulitis and acute enterocolitis. Adjunctive therapy in irritable bowel syndrome (irritable colon, spastic colon, mucous colitis) and functional gastrointestinal disorders. Adjunctive therapy in the treatment of neurogenic bladder and neurogenic bowel disturbances (including the splenic flexure syndrome and neurogenic colon). Also for infant colic (drops). In combination with morphine or other narcotics in symptomatic relief of biliary and renal colic; as a drying agent in the relief of symptoms of acute rhinitis; parkinsonism to reduce rigidity and hyperhidrosis; and in therapy of poisoning by anticholinesterase agents.
Hyoscyamine may be used to reduce pain and hypersecretion in pancreatitis. Hyoscyamine may be used in certain cases of partial heart block associated with vagal activity.
Contra-Indications: Glaucoma, obstructive uropathy (for example, bladder neck obstruction due to prostatic hypertrophy); obstructive disease of the gastrointestinal tract (as in achalasia, pyloroduodenal stenosis); paralytic ileus; intestinal atony of the elderly or debilitated patients; unstable cardiovascular status in acute hemorrhage; severe ulcerative colitis; toxic megacolon complicating ulcerative colitis; myasthenia gravis.
Manufacturers’ Warnings In Clinical States: In the presence of high environmental temperature, heat prostration can occur (fever and heat stroke due to decreased sweating). Diarrhea may be an early symptom of incomplete intestinal obstruction, especially in patients with ileostomy or colostomy; treatment with this drug would be inappropriate and possibly harmful.
Occupational Hazards: Drowsiness or blurred vision may occur. In this event, the patient should be warned not to engage in activities requiring mental alertness such as operating a motor vehicle or other machinery or to perform hazardous work while taking this drug.
Psychosis has been reported in sensitive individuals given anticholinergic drugs. CNS signs and symptoms include confusion, disorientation, short-term memory loss, hallucinations, dysarthria, ataxia, coma, euphoria, decreased anxiety, fatigue, insomnia, agitation and mannerisms, and inappropriate affect. These CNS signs and symptoms usually resolve within 12 to 48 hours after discontinuation of the drug.
Precautions: Use with caution in patients with autonomic neuropathy, hyperthyroidism, coronary heart disease, congestive heart failure, cardiac arrhythmias, hypertension and renal failure. Investigate any tachycardia before giving any anticholinergic drug since they may increase the heart rate. Use with caution in patients with hiatal hernia associated with reflux esophagitis.
Occupational Hazards: Hyoscyamine may cause drowsiness, dizziness or blurred vision; observe caution before driving, using machinery or performing other tasks requiring mental alertness.
Use of hyoscyamine may decrease sweating resulting in heat prostration, fever or heat stroke; febrile patients or those who may be exposed to elevated environmental temperatures should use caution.
Drug Interactions: Additive adverse effects resulting from cholinergic blockade may occur when hyoscyamine is administered concomitantly with other antimuscarinics, amantadine, haloperidol, phenothiazines, MAO inhibitors, tricyclic antidepressants or some antihistamines.
Antacids may interfere with the absorption of hyoscyamine. Administer before meals; antacids after meals.
Carcinogenesis, Mutagenesis, Impairment of Fertility: No long-term studies in animals have been performed to determine the carcinogenic, mutagenic, or impairment of fertility potential of hyoscyamine; however, over 30 years of marketing experience shows no demonstrable evidence of a problem.
Pregnancy: Animal reproduction studies have not been conducted with hyoscyamine. It is also not known whether it can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. It should be given to a pregnant woman only if clearly needed.
Lactation: Hyoscyamine is excreted in human milk. Caution should be exercised when it is administered to a nursing woman.
Adverse Reactions: Not all of the following adverse reactions have been reported with hyoscyamine. The following adverse reactions have been reported for pharmacologically similar drugs with anticholinergic/antispasmodic action. Adverse reactions may include dryness of the mouth, urinary hesitancy and retention, blurred vision, tachycardia, palpitations, mydriasis, cycloplegia, increased ocular tension, loss of taste, headache, nervousness, drowsiness, weakness, dizziness, insomnia, nausea, vomiting, impotence, suppression of lactation, constipation, bloated feeling, allergic reactions or drug idiosyncrasies, urticaria and other dermal manifestations, ataxia, speech disturbance, some degree of mental confusion and/or excitement (especially in elderly persons), and decreased sweating.
Symptoms And Treatment Of Overdose: Symptoms: Headache, nausea, vomiting, blurred vision, dilated pupils, hot dry skin, dizziness, dryness of the mouth, difficulty in swallowing, and CNS stimulation.
Treatment: Immediate lavage of the stomach and injection of physostigmine 0.5 to 2 mg i.v. and repeat as necessary up to a total of 5 mg. Fever may be treated symptomatically (tepid water sponge baths, hypothermic blanket). Excitement to a degree which demands attention may be managed with sodium thiopental 2% solution given slowly i.v. or chloral hydrate (100-200 mL of a 2% solution) by rectal infusion. In the event of progression of the curare-like effect to paralysis of the respiratory muscles, artificial respiration should be instituted and maintained until effective respiratory action returns.
Dosage And Administration: Dosage may be adjusted according to the conditions and severity of symptoms. The tablets may be taken sublingually or orally.
Adults: 1 or 2 tablets every 4 hours or as needed.
Availability And Storage: Each pale blue-green, octagonal, scored tablet, engraved with SCHWARZ logo and 532, contains: hyoscyamine sulfate 0.125 mg. Nonmedicinal ingredients: colloidal silicon dioxide, dextrates, FD&C Green #3, mannitol, natural peppermint flavor, purified water and stearic acid. Gluten- and tartrazine-free. Bottles of 100.
LEVSIN® Rivex Pharma Hyoscyamine Sulfate Antispasmodic