Hyoscyamine
DESCRIPTION:
ACTIONS/CLINICAL PHARMACOLOGY:
Through its parasympatholytic action, hyoscyamine relaxes smooth muscle spasm
resulting from parasympathetic stimulation. It inhibits gastrointestinal
propulsive motility and decreases gastric acid secretion. It also controls
excessive pharyngeal, tracheal and bronchial secretions. It is the lambda-isomer
of atropine and therefore exhibits the same clinical effects as atropine. It is,
however, approximately twice as active peripherally as atropine, since the
latter is the racemic (d lambda) form of hyoscyamine and d-hyoscyamine possesses
only a very weak anti-cholinergic action. Since only one-half the atropine dose
is required for lambda-hyoscyamine, it has only one- half the unwanted central
effects of atropine. (REF. 1)
INDICATIONS AND USAGE:
In the management of disorders of the lower urinary tract associated with
hypermotility. Although specific therapy is often required to remove the
underlying cause of spasm, HYOSCYAMINE Tablets and HYOSCYAMINE Capsules are
offered as antispasmodic agent dosage forms which may be combined with other
forms of therapy where indicated.
HYOSCYAMINE Tablets and HYOSCYAMINE capsules are effective as adjunctive therapy
in the treatment of peptic ulcer and irritable bowel syndrome (irritable colon,
spastic colon, mucous colitis), acute enterocolitis and other functional
gastrointestinal disorders.
HYOSCYAMINE Tablets and HYOSCYAMINE Capsules can also be used to control gastric
secretion, visceral spasm and hypermotility in cystitis, pylorospasm and
associated abdominal cramps. May be used in functional intestinal disorders to
reduce symptoms such as those seen in mild dysenteries and diverticulitis. They
are indicated (along with appropriate analgesics) in symptomatic relief of
biliary and renal colic.
CONTRAINDICATIONS:
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
elderly or debilitated patients; unstable cardiovascular status in acute
hemorrhage; severe ulcerative colitis; toxic megacolon complicating ulcerative
colitis; myasthenia gravis. Hypersensitivity to any of the ingredients.
WARNINGS:
In the presence of high environmental temperature, heat prostration can occur
with drug use (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. In this instance, treatment with this drug would be
inappropriate and possibly harmful. Like other anticholinergic agents, these
products may produce drowsiness or blurred vision. 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.
PRECAUTIONS:
GENERAL: Use with caution in patients with autonomic neuropathy,
hyperthyroidism, coronary heart disease, congestive heart failure, cardiac
arrhythmias, and hypertension. 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.
INFORMATION FOR PATIENTS: HYOSCYAMINE Tablets and HYOSCYAMINE Capsules may cause
drowsiness, dizziness or blurred vision; patients should observe caution before
driving, using machinery or performing other tasks requiring mental alertness.
Use of HYOSCYAMINE Tablets or HYOSCYAMINE- M Capsules 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(R) Tablets or HYOSCYAMINE Capsules are administered concomitantly with
other antimuscarinics, amantadine, haloperidol, phenothiazines, monoamine
oxidase (MAO) inhibitors, tricyclic antidepressants or some antihistamines.
Antacids may interfere with the absorption of HYOSCYAMINE Tablets or HYOSCYAMINE
Capsules; take HYOSCYAMINE Tablets or HYOSCYAMINE Capsules before meals and
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 Tablets and HYOSCYAMINE Capsules.
PREGNANCY CATEGORY C: Animal reproduction studies have not been conducted with
HYOSCYAMINE Tablets or HYOSCYAMINE Capsules. It is also not known whether
HYOSCYAMINE Tablets or HYOSCYAMINE Capsules can cause fetal harm when administered
to a pregnant woman or can affect reproduction capacity. HYOSCYAMINE Tablets or
HYOSCYAMINE Capsules should be taken by a pregnant woman only if clearly needed.
NURSING MOTHERS: Hyoscyamine is excreted in human milk. Caution should be
exercised when HYOSCYAMINE Tablets or HYOSCYAMINE Capsules are administered to a
nursing woman.
DRUG INTERACTIONS:
Additive adverse effects resulting from cholinergic blockade may occur when
HYOSCYAMINE(R) Tablets or HYOSCYAMINE Capsules are administered concomitantly with
other antimuscarinics, amantadine, haloperidol, phenothiazines, monoamine
oxidase (MAO) inhibitors, tricyclic antidepressants or some antihistamines.
Antacids may interfere with the absorption of HYOSCYAMINE Tablets or HYOSCYAMINE
Capsules; take HYOSCYAMINE Tablets or HYOSCYAMINE Capsules before meals and
antacids after meals.
(See Also PRECAUTIONS)
ADVERSE REACTIONS:
Adverse reactions may include dryness of the mouth; urinary hesitancy and
retention; blurred vision; tachycardia; palpitations; mydriasis; cycloplegia;
increased ocular tension; headache; nervousness; drowsiness; weakness;
suppression of lactation; allergic reactions or drug idiosyncrasies; urticaria
and other dermal manifestations; and decreased sweating. NOTE: Slight dryness of
the mouth is an indication that parasympathetic blockage is effective.
DRUG ABUSE AND DEPENDENCE:
A dependence on the use of HYOSCYAMINE Tablets or HYOSCYAMINE Capsules has not
been reported and due to the nature of their ingredients, abuse of HYOSCYAMINE
Tablets or HYOSCYAMINE Capsules is not expected.
OVERDOSAGE:
Symptoms of overdosage include severe dryness of the mouth, nose, throat, and
hot dry flushed skin, hyperpyrexia (especially in children), difficulty or
inability to swallow, difficult speech, dilated pupils until iris almost
disappears, restlessness and garrulity indicating an irritability of the brain,
marked tremors, convulsions, respiratory failure, death. (REF. 1) In adults,
symptoms of overdosage may begin in the range of ingestion of 0.6 to 1 mg with
doses exceeding 1-2 mg eliciting more profound toxicity. Measures to be taken
are immediate lavage of the stomach and injection of physostigmine 0.5 to 2 mg
intravenously and repeated 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 intravenously or chloral hydrate (100-200
ml. of a 2% solution) by rectal infusion.
DOSAGE AND ADMINISTRATION:
ADULTS: HYOSCYAMINE Tablets--One or two tablets four times daily or fewer if
needed. HYOSCYAMINE Capsules--One capsule every twelve hours.
CHILDREN (12 AND UNDER): Reduce dosage in proportion to age and weight.
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