Pharmacology of Neurotransmitters and Medications

Neurotransmitters and Nervous System Functions

• Norepinephrine activates the fight or flight response through adrenergic receptors.
• Acetylcholine (ACh) is responsible for activating the rest and digest functions of the parasympathetic nervous system.
• Cholinergic drugs induce rest and digest activities.

Medications and Treatments

• Doxazosin lowers blood pressure and alleviates benign prostatic hyperplasia (BPH) symptoms.
• Norepinephrine causes vasoconstriction, increasing blood pressure by stimulating alpha adrenergic receptors.
• Dobutamine acts as a selective beta-1 adrenergic inotrope with minimal effect on blood pressure.
• Pseudoephedrine is used therapeutically as a sinus decongestant.
• Pyridostigmine is primarily prescribed for myasthenia gravis.
• Donepezil, a cholinesterase inhibitor, enhances memory function.
• Physostigmine serves as an antidote for anticholinergic toxicity.
• Dicyclomine is used to treat irritable bowel syndrome (IBS).
• Levodopa/carbidopa is a combination medication that converts to dopamine in the central nervous system (CNS) and is used to treat Parkinson's disease.
• Succinylcholine and Rocuronium are both neuromuscular blockers used during surgical procedures to relax muscles.
• Ginkgo Biloba is an over-the-counter supplement that may improve memory.
• Interferon Beta1A and Interferon Beta1B are used for managing multiple sclerosis.

Drug Mechanisms and Classes

• Barbiturates and benzodiazepines potentiate GABA, influencing relaxation and sedation.
• Inotropes increase the force of cardiac contractions, subsequently elevating blood pressure.
• Dobutamine is particularly effective in treating cardiogenic shock.
• Hypovolemic shock is associated with significant blood loss.
• Crystalloid fluids include isotonic solutions such as normal saline, lactated Ringer's (LR), D5W, and Plasmalyte.
• Anticholinergics can induce fight or flight responses.

Side Effects and Reactions

• Epinephrine can cause side effects such as tremors, palpitations, tachycardia, dizziness, and headaches.
• Bethanechol may lead to hypertension, excessive salivation, abnormal cramps, diaphoresis, and increased urination.
• Dicyclomine can cause blurred vision, dizziness, or drowsiness.
• Seizure treatment with phenytoin (Dilantin) may result in gingival hyperplasia, dizziness, gastrointestinal upset, and rash.
• Common side effects of anticholinergic medications include constipation, dry mouth, urinary retention, and blurred vision.

Adrenergic Receptors and Responses

• Alpha-1 adrenergic receptor stimulation leads to vasoconstriction, increased blood pressure, mydriasis (dilated pupils), and enhanced bladder sphincter closure.
• Stimulation of alpha-2 adrenergic receptors results in inhibition of norepinephrine, acetylcholine, and insulin release.
• Beta-1 adrenergic receptor stimulation increases heart rate, contractility, renin release, and lipolysis.
• Beta-2 adrenergic receptor activation induces vasodilation, smooth muscle relaxation, reduced blood pressure, bronchodilation, and decreased peripheral vascular resistance.

Administration and Monitoring

• Doxazosin should be administered before bedtime for patients aged 65 and older to mitigate orthostatic hypertension.
• Nursing actions for norepinephrine administration include monitoring blood pressure and heart rate, using a dedicated IV site, and avoiding concurrent medications in the IV line.
• High-dose dopamine enhances heart contraction force, increasing cardiac output and blood pressure.

Additional Information

• Atropine is an anticholinergic drug used to dilate pupils for eye examinations.
• Epinephrine is indicated for the treatment of anaphylaxis.
• Flumazenil is the antidote for diazepam overdose.
• The therapeutic use of Methocarbamol is as a muscle relaxer.
• Adjunctive therapies for seizures may include dietary modifications like a ketogenic diet.