Pharmacology of Cholinergic Drugs

Drugs that attach to adrenergic receptors but prevent the activation of the sympathetic nervous system (SNS).

They either block the alpha1/2 receptors or the beta1/2 receptors in the sympathetic nervous system.

Drugs that prevent the stimulation of alpha1 receptors, leading to relaxation of smooth muscles.

They help reduce blood pressure by relaxing blood vessels and lowering resistance to blood flow.

They can help with benign prostatic hyperplasia (BPH) by reducing urinary outflow resistance.

Alpha blockers dilate blood vessels, including arteries and veins, helping lower blood pressure.

Alpha blockers create a competitive or noncompetitive blockade of alpha receptors, preventing their activation.

They prevent the activation of alpha1 receptors which in turn prevents smooth muscle contraction.

Drugs that work by mimicking the effects of acetylcholine (Ach), a neurotransmitter that activates the parasympathetic nervous system (PSNS).

These drugs directly bind to and activate acetylcholine receptors, causing a similar response to the natural neurotransmitter.

These drugs increase the amount of acetylcholine available by inhibiting the enzyme that breaks it down, acetylcholinesterase.

A severe adverse effect of cholinergic drugs that can lead to life-threatening complications due to excessive PSNS activation.

Common symptoms include bradycardia, hypotension, nausea, vomiting, increased secretions, and even circulatory collapse.

Alpha blockers are medications used to treat a variety of conditions by blocking the stimulation of alpha receptors in the sympathetic nervous system.

Alpha blockers are categorized as either selective or nonselective, depending on whether they block only specific subtypes of alpha receptors or a broad range of alpha receptors.

A primary adverse effect of alpha blockers is causing a drop in blood pressure, particularly when standing up due to vasodilation. This condition is known as orthostatic hypotension.

Alpha blockers are also helpful in diagnosing and treating pheochromocytoma, a tumor of the adrenal gland producing hormones that cause hypertension.

Alpha blockers can also be used in treating benign prostatic hyperplasia (BPH) by relaxing smooth muscles in the prostate gland and urinary bladder, improving urinary flow.

Alpha blockers can be beneficial in managing Raynaud's disease, acrocyanosis, and frostbite by reducing vasoconstriction in the extremities, improving blood flow to cold areas.

When administering alpha blockers, it is important to educate the patient about potential adverse effects, such as orthostatic hypotension, and advise them to change positions slowly to minimize the risk.

A drug that reverses the effects of nondepolarizing neuromuscular blocking agents, treats severe tricyclic antidepressant overdose, and acts as an antidote for anticholinergic poisoning.

A medication used to treat Alzheimer's disease. It acts as an NMDA receptor antagonist, blocking the activity of these receptors in the central nervous system.

A herbal supplement often taken to improve memory, treat peripheral artery disease, vertigo, and tinnitus. However, it can cause gastrointestinal upset, headaches, bleeding, and allergic reactions.

A potential adverse effect of ginkgo biloba that may be especially concerning for patients on multiple medications, including NSAIDs, oral antidiabetics, thyroid replacement hormone, and beta blockers.

A condition characterized by muscle weakness that improves with rest and worsens with activity. Treatment often involves cholinergic medications taken 30 minutes before meals.

A group of drugs used to treat Alzheimer's disease. While they can manage symptoms, they don't cure the disease and their therapeutic effects may take up to 6 weeks to appear.

A medication used to treat cholinergic crisis by reversing excessive cholinergic activity.

Drugs that block or inhibit the actions of acetylcholine (ACh) in the parasympathetic nervous system (PSNS).

They compete with ACh for binding at muscarinic receptors in the PSNS, preventing ACh from binding and causing its effects.

Atropine, dicyclomine, glycopyrrolate, oxybutynin, scopolamine, and tolterodine.

Cholinergic-blocking drugs can affect the heart's conduction system, potentially causing decreased heart rate at low doses and increased heart rate at high doses, by blocking inhibitory vagal effects on the SA and AV nodes.

Low doses can decrease muscle rigidity and tremors in conditions like Parkinson's Disease, while high doses can cause drowsiness, disorientation, and hallucinations.

Cholinergic-blocking drugs dilate pupils (mydriasis) and decrease accommodation by paralyzing ciliary muscles (cycloplegia).

Cholinergic-blocking drugs can reduce bronchial secretions, salivation, and sweating.

Altered mental status is a common sign of atropine overdose.

They are used to treat conditions involving excessive activation of the PSNS, such as irritable bowel syndrome, overactive bladder, and asthma.

Common side effects include dry mouth, blurred vision, constipation, and urinary retention.

Glycopyrrolate is a cholinergic-blocking drug given before surgery to prevent excessive secretions in the airway, which can interfere with breathing during surgery.

Tolterodine is a cholinergic-blocking drug used to treat an overactive bladder, by relaxing the bladder muscle and reducing urinary frequency and urgency.

Angle-closure glaucoma is a condition where the fluid pressure inside the eye increases. Cholinergic-blocking drugs can worsen this condition by dilating the pupils and hindering fluid drainage.

These drugs may worsen asthma or other respiratory distress by decreasing bronchial secretions and relaxing smooth muscles in the airways.

Myasthenia gravis is a neuromuscular disorder characterized by muscle weakness. Cholinergic-blocking drugs can exacerbate this weakness.