SCOPOLAMINE

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Scopolamine is an anticholinergic drug derived from plants in the nightshade family. It has several important applications in anesthesia and perioperative care, which include:

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1. Prevention of postoperative nausea and vomiting (PONV): Scopolamine is commonly used as a prophylactic measure to reduce the incidence of PONV, a frequent and distressing complication following surgery. PONV can lead to patient discomfort, prolonged hospital stays, and increased healthcare costs. Scopolamine works by blocking the muscarinic acetylcholine receptors in the vomiting center of the brain, effectively reducing the risk of PONV.

2. Preoperative sedation: Scopolamine has sedative properties, making it useful for preoperative sedation in certain cases. It can help alleviate anxiety and promote relaxation before surgery, contributing to improved patient comfort and overall experience.

3. Antisialagogue effect: Scopolamine reduces salivary and bronchial secretions, which can be advantageous during anesthesia induction and intubation. Reduced secretions can lead to a smoother intubation process, decreased risk of aspiration, and improved visualization during laryngoscopy.

4. Amnestic effect: Scopolamine has an amnestic effect, which can help prevent the formation of distressing memories related to the surgical experience. This can contribute to a more positive patient experience and reduce the risk of postoperative psychological issues, such as post-traumatic stress disorder (PTSD).

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Scopolamine's mechanism of action is primarily related to its ability to block muscarinic acetylcholine receptors, both centrally and peripherally. Here are the main steps in scopolamine's mechanism of action:

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1. Central action: In the central nervous system, scopolamine blocks muscarinic acetylcholine receptors, particularly in the vestibular nuclei and the vomiting center in the medulla. By inhibiting these receptors, scopolamine reduces the transmission of nerve impulses between the vestibular apparatus in the inner ear and the vomiting center, which helps prevent and treat motion sickness.

2. Peripheral action: Scopolamine also has peripheral anticholinergic effects, blocking muscarinic acetylcholine receptors in the smooth muscles and glands of the gastrointestinal tract, respiratory system, and other tissues. This action reduces smooth muscle contraction and secretion, which may contribute to its antiemetic effects.

3. Antisialagogue effect: By blocking muscarinic acetylcholine receptors in the salivary glands, scopolamine reduces saliva production, which can be helpful in some surgical procedures.

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                                                                                         Key points about Scopolamine

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• Scopolamine competitively inhibits G-protein coupled post-ganglionic muscarinic receptors for acetylcholine and acts as a nonselective muscarinic antagonist.

 

• It can enter the central nervous system (CNS) and produce symptoms characterized as central anticholinergic syndrome.

 

• The most common side effects include blurry vision, dilated pupils and dry mouth.

 

• Due to scopolamine’s anticholinergic properties, its use can decrease gastrointestinal motility and cause urinary retention.

 

• Contraindications for scopolamine include allergy to belladonna alkaloids and angle-closure glaucoma.

 

• Patients should also discontinue using scopolamine patch before MRI. One of the four layers contains metal and can burn the skin during MRI imaging.

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