Hyoscyamine sulfate is used as an adjunct in the treatment of peptic ulcer disease. As with other antimuscarinics, there are no conclusive data from well-controlled studies that indicate that, in usually recommended dosage, hyoscyamine sulfate aids in the healing, decreases the rate of recurrence, or prevents complications of peptic ulcers. In addition, in patients with gastric ulcer, antimuscarinics may delay gastric emptying and result in antral stasis.
Hyoscyamine sulfate is used as an adjunct in the treatment of functional GI disorders such as irritable bowel syndrome. As with other antimuscarinics, hyoscyamine sulfate has limited efficacy in the treatment of these disorders and should be used only if other measures (e.g., diet, sedation, counseling, amelioration of environmental factors) have been of little or no benefit. Although hyoscyamine sulfate has also been used in combination with phenobarbital in the treatment of irritable bowel syndrome, attempts to substantiate claims of efficacy for fixed combinations that include an antimuscarinic and phenobarbital have generally failed and these combinations are generally considered as lacking substantial evidence of efficacy in the treatment of this condition.
Although hyoscyamine sulfate has been used in the treatment of hypermotility and diarrhea associated with GI disorders such as ulcerative colitis, dysentery, shigellosis, and Clostridium difficile-associated diarrhea and colitis (also known as antibiotic-associated pseudomembranous colitis), the drug should be used with extreme caution, if at all, in patients with these conditions.
Genitourinary Tract Disorders
Hyoscyamine and hyoscyamine sulfate have been used as adjunctive therapy in the management of hypermotility disorders of the lower urinary tract. Although these agents may provide symptomatic relief, the underlying cause should be determined and specifically treated. Appropriate anti-infective therapy should be initiated whenever urinary tract infection is present. Although hyoscyamine has been used in combination with methenamine and other drugs, the dose of methenamine (40.8 mg) contained in most combination preparations was inadequate for use as an anti-infective. With the exception of uninhibited or reflex neurogenic bladder, there is generally little evidence to support the use of antimuscarinics in the treatment of various genitourinary disorders.
Hyoscyamine sulfate oral solution (drops) and elixir have been used in the treatment of infant colic. However, there is minimal evidence from well-designed clinical studies of the efficacy of antimuscarinics in the management of this condition. Infant colic is considered a benign, self-limiting condition that tends to resolve spontaneously and not require medical treatment.
Hyoscyamine sulfate injection has been used as a preoperative medication to inhibit salivation and excessive secretions of the respiratory tract; however, the current practice of using thiopental (no longer commercially available in the US), halothane, or similar general anesthetics that do not stimulate the production of salivary and tracheobronchial secretions has reduced the need to control excessive respiratory secretions during surgery.
Although hyoscyamine sulfate injection has been used prophylactically to reduce the volume and acidity of gastric secretions and to prevent acid-aspiration pneumonitis during surgery, antimuscarinics have not been shown to be effective for this use.
Hyoscyamine sulfate injection may be used to block cardiac vagal inhibitory reflexes during induction of anesthesia and intubation. The drug prevents cholinergic effects during surgery, such as cardiac arrhythmias, hypotension, and bradycardia, which may result from traction on viscera (with resultant vagal stimulation), stimulation of the carotid sinus, or administration of drugs (e.g., succinylcholine).
Hyoscyamine sulfate injection is administered concurrently with anticholinesterase agents (e.g., neostigmine) to block the adverse muscarinic effects of these latter agents when they are used after surgery to terminate curarization. For further discussion on the use of hyoscyamine sulfate injection in surgery,
Hyoscyamine sulfate injection is used as an antidote in the treatment of cholinesterase inhibitor toxicity. Hyoscyamine sulfate oral and sublingual preparations also are used in the treatment of cholinesterase inhibitor toxicity. Hyoscyamine sulfate also has been used as a drying agent in the relief of symptoms of acute rhinitis and as adjunctive therapy in the treatment of parkinsonian syndrome to reduce rigidity and tremors and to control associated sialorrhea and hyperhidrosis. For further discussion on the use of antimuscarinics in these conditions,
Hyoscyamine sulfate injection has been used to facilitate endoscopy or hypotonic duodenography by reducing GI motility; however, glucagon appears to be more effective and is generally preferred in this examination. Hyoscyamine sulfate injection also has been used to increase visualization of the urinary tract in excretion urography.
Hyoscyamine sulfate has been used in conjunction with morphine or other opiates for the symptomatic relief of biliary or renal colic; however, since antimuscarinics exert only a weak biliary antispasmodic action, these drugs should not be relied on in the treatment of biliary tract disease. Hyoscyamine sulfate injection has been used to reduce pain and hypersecretion in pancreatitis; however, there is little, if any, evidence that antimuscarinics improve the prognosis of the disease. Hyoscyamine sulfate injection also has been used concomitantly with a cholinesterase reactivator (e.g., pralidoxime) to reverse muscarinic effects associated with toxic exposure to anticholinesterase compounds (e.g., organophosphate pesticides); however, other antimuscarinic agents (principally atropine) are more commonly used for this purpose. In some patients, hyoscyamine sulfate injection may be useful in treating partial heart block associated with vagal activity.