MOTION SICKNESS - SCOPOLAMINE RX

Question 1

Scopolamine indications:

Answer 1

1) Motion sickness
2) Postoperative N/V
3) Preoperative
4) Surgery
5) Parkinson’s disease

Question 2

Scopolamine Counseling Instructions

Answer 2

Apply to clean, dry, hairless area behind the ear
Press firmly for at least 30 secs to seal edges of patch
Apply 4 hours before needed effect
Wash hand w/ soap before and after
Renew patch only every 3 days by placing the patch behind the other ear
Remove before MRI or it will burn the skin since there

Question 3

What are the common side effects of scopolamine?

Answer 3

The common side effects of scopolamine include dry mouth, drowsiness, blurry vision, and widened pupils (mydriasis).

Question 4

What should be done if rare side effects such as disorientation, confusion, hallucinations, or palpitations occur with scopolamine use?

Answer 4

If rare side effects such as disorientation, confusion, hallucinations, or palpitations occur, the patch should be removed, and a healthcare provider should be contacted.

Question 5

What is the mechanism of action of scopolamine for motion sickness?

Answer 5

Scopolamine acts as a competitive inhibitor at postganglionic muscarinic receptor sites of the parasympathetic nervous system. It also acts on smooth muscles that respond to acetylcholine but lack cholinergic innervation.

Acetylcholine (ACh) is a neurotransmitter that can signal through ligand-gated cation channels (nicotinic receptors) and G-protein-coupled muscarinic receptors (mAChRs). ACh signalling via mAChRs located in the central nervous system (CNS) and periphery can regulate smooth muscle contraction, glandular secretions, heart rate, and various neurological phenomena such as learning and memory.2,3 mAChRs can be divided into five subtypes, M1-M5, expressed at various levels throughout the brain.3 Also, M2 receptors are found in the heart and M3 receptors in smooth muscles, mediating effects apart from the direct modulation of the parasympathetic nervous system.4 While M1, M3, and M5 mAChRs primarily couple to Gq proteins to activate phospholipase C, M2 and M4 mainly couple to Gi/o proteins to inhibit adenylyl cyclase and modulate cellular ion flow.3 This system, in part, helps to control physiological responses such as nausea and vomiting.9

Scopolamine acts as a non-selective competitive inhibitor of M1-M5 mAChRs, albeit with weaker M5 inhibition; as such, scopolamine is an anticholinergic with various dose-dependent therapeutic and adverse effects.4,5,6 The exact mechanism(s) of action of scopolamine remains poorly understood. Recent evidence suggests that M1 (and possibly M2) mAChR antagonism at interneurons acts through inhibition of downstream neurotransmitter release and subsequent pyramidal neuron activation to mediate neurological responses associated with stress and depression.7 Similar antagonism of M4 and M5 receptors is associated with potential therapeutic benefits in neurological conditions such as schizophrenia and substance abuse disorders.3 The significance of these observations to scopolamine’s current therapeutic indications of preventing nausea and vomiting is unclear but is linked to its anticholinergic effect and ability to alter signalling through the CNS associated with vomiting.5,9

Question 6

How does scopolamine work in the central nervous system (CNS)?

Answer 6

Scopolamine acts in the CNS by blocking cholinergic transmission from the vestibular nuclei to higher centers and from the reticular formation to the vomiting center.

Question 7

Scopolamine Contraindications:

Answer 7

1) Hypersensitivity to belladonna alkaloids
2) Close-angle glaucoma