What is the effect of Hyoscyamine (anticholinergic medication)?

From the Guidelines

Hyoscyamine is not the preferred treatment option for dyspnea, and its use should be considered only for reducing excessive secretions associated with dyspnea, with scopolamine, atropine, and glycopyrrolate being alternative options. When considering the use of hyoscyamine for dyspnea, it is essential to weigh the potential benefits against the risks of anticholinergic side effects, such as dry mouth, blurred vision, urinary retention, and constipation 1. The typical dosing for hyoscyamine is 0.125-0.25 mg every 4 hours as needed, with extended-release formulations available at 0.375-0.75 mg taken twice daily.

Some key points to consider when using hyoscyamine for dyspnea include:

• Hyoscyamine should be used with caution in elderly patients and those with glaucoma, urinary retention, or certain heart conditions 1.
• The medication typically begins working within 30-60 minutes for immediate-release forms and should be taken before meals for optimal effect in treating digestive symptoms.
• Glycopyrrolate does not effectively cross the blood-brain barrier and is less likely than the other drug options to cause delirium, but this agent can produce anticholinergic side effects 1.
• Scopolamine can be administered subcutaneously or transdermally; physicians should be aware that the onset of benefit for transdermal scopolamine patches is about 12 hours, and they are thus not an appropriate choice for imminently dying patients 1.

It is crucial to prioritize the management of underlying causes or comorbid conditions, such as using chemotherapy or radiation therapy, therapeutic procedures for cardiac, pleural, or abdominal fluid, bronchoscopic therapy, or bronchodilators, diuretics, steroids, antibiotics, transfusions, or anticoagulants for pulmonary emboli 1. Nonpharmacologic interventions, including the use of handheld fans directed at the face, supplemental oxygen, and mechanical ventilation, should also be considered 1.

From the FDA Drug Label

PRECAUTIONS General:Use with caution in patients with: autonomic neuropathy, hyperthyroidism, coronary heart disease, congestive heart failure, cardiac arrythmias, hypertension, and renal disease. WARNINGS In the presence of high environmental temperature, heat prostration can occur with drug use (fever and heat stroke due to decreased sweating). The answer to the question about hycosamine (also known as hyoscyamine) is that it should be used with caution in various medical conditions, including those related to the heart, and it may produce adverse effects such as drowsiness, dizziness, and blurred vision 2 2.

• Key warnings include the risk of heat prostration and CNS signs and symptoms such as confusion, disorientation, and hallucinations.
• Special considerations should be taken for patients with renal disease, as the drug is substantially excreted by the kidney, and for elderly patients, who may have decreased hepatic, renal, or cardiac function.

From the Research

Hyoscine and Hyoscyamine

• Hyoscine and hyoscyamine are anticholinergic/antimuscarinic agents used to treat chronic abdominal pain in patients with functional GI disorders/disorders of gut-brain interaction, including irritable bowel syndrome, functional dyspepsia, and centrally mediated abdominal pain syndrome 3.
• These agents work by inhibiting GI smooth muscle contraction, and are often used in combination with other therapies to relieve symptoms of abdominal pain and bloating 4, 5.

Efficacy and Safety

• The efficacy and safety of hyoscine butylbromide (HBB) and anisodamine for treating acute gastric or intestinal spasm-like pain have been compared in a randomized, double-blinded, multicenter Phase III trial, which found that HBB 20 mg was not inferior to anisodamine 10 mg in pain relief 6.
• Antispasmodic agents, including hyoscine and hyoscyamine, have been found to be effective in treating irritable bowel syndrome (IBS), with a significant improvement in global symptoms and abdominal pain compared to placebo 4.
• However, the efficacy and safety of these agents can vary depending on the specific agent, dosage, and patient population, and should be considered on an individual basis rather than prescribed based on information across the broad class of agents 3.

Treatment Options

• Antispasmodic agents, including hyoscine and hyoscyamine, are often used in combination with other therapies, such as fiber, antidepressants, and probiotics, to treat IBS and other functional GI disorders 4, 5.
• Emerging data have confirmed the efficacy of novel molecular treatments, including therapies targeting gastrointestinal mucosal chloride channels and guanylate cyclase-C receptors, as well as highly selective agents influencing serotonergic transmission, which show promise for the treatment of IBS 5.