Pharmacology of Adrenergic and Cholinergic Drugs

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Questions and Answers

What is a primary action of adrenergic drugs on the cardiovascular system?

Increased cardiac output (correct)

Decrease in heart rate

Enhanced gastric motility

Constriction of all blood vessels

Which adrenergic receptor subtype is primarily associated with smooth muscle relaxation in the bronchi?

Beta 1 (β1)

Beta 2 (β2) (correct)

Alpha 1 (α1)

Alpha 2 (α2)

Which of the following is NOT a use of adrenergic drugs?

Temporary treatment of heart block

Management of superficial bleeding

Treatment of hypovolemic shock

Cure for diabetes (correct)

Which of the following adrenergic drugs is commonly used in medical practice?

Isoproterenol (Isuprel) Signup and view all the answers

What metabolic effect do adrenergic drugs have?

Increased liberation of fatty acids Signup and view all the answers

What is the primary purpose of cholinergic drugs in urinary retention?

To promote spontaneous urine passage Signup and view all the answers

Which of the following is a common adverse effect of cholinergic drug administration?

Nausea Signup and view all the answers

What should be monitored closely when a patient is taking cholinergic drugs?

Vital signs and symptoms Signup and view all the answers

In which conditions are cholinergic drugs contraindicated?

Hypersensitivity and cardiac arrhythmias Signup and view all the answers

What are symptoms of a cholinergic crisis?

Severe abdominal cramping and muscle weakness Signup and view all the answers

What is the role of atropine in cases of cholinergic drug overdosage?

To block the action of acetylcholine Signup and view all the answers

Which of the following is NOT a cholinergic blocking drug?

Bethanechol Signup and view all the answers

What does the term 'anticholinergic' refer to?

Drugs that block acetylcholine's effects Signup and view all the answers

What is the primary use of Dobutamine?

Cardiac decompensation due to depressed contractility Signup and view all the answers

Which adrenergic drug is commonly used to treat shock related to renal failure?

Dopamine Signup and view all the answers

What side effect is NOT associated with Epinephrine?

Drowsiness Signup and view all the answers

How is shock defined?

A life-threatening condition of inadequate perfusion Signup and view all the answers

During the early stages of shock, how do the extremities typically appear?

Warm and pink Signup and view all the answers

Which type of shock is characterized by inadequate blood volume?

Hypovolemic shock Signup and view all the answers

What is a common use of Isoproterenol?

Treatment of bronchospasm during anesthesia Signup and view all the answers

What is a potential side effect of Dopamine?

Nausea Signup and view all the answers

What is the primary use of phentolamine?

To prevent tissue damage from drug extravasation Signup and view all the answers

Which side effect is NOT associated with α-adrenergic blocking drugs?

Hyperactivity Signup and view all the answers

Why are β-adrenergic blocking drugs used cautiously in patients after a recent myocardial infarction?

They may reduce blood pressure excessively Signup and view all the answers

What is the primary action of β-adrenergic blocking drugs on the heart?

Decrease cardiac workload and oxygen consumption Signup and view all the answers

Which of the following is NOT a contraindication for adrenergic blocking drugs?

General anxiety disorder Signup and view all the answers

Which β-blocker is commonly used for migraine headaches?

Propranolol Signup and view all the answers

What therapeutic effect do topical β-adrenergic blocking drugs have in treating glaucoma?

Reduce aqueous humor production Signup and view all the answers

Which of the following side effects might be expected with β-adrenergic blocking drugs?

Bradycardia Signup and view all the answers

What is the primary action of cholinergic blocking drugs?

They inhibit the activity of acetylcholine in parasympathetic fibers. Signup and view all the answers

Which effect is NOT associated with cholinergic blocking drugs?

Myopia Signup and view all the answers

What effect do cholinergic blocking drugs have on the gastrointestinal tract?

Decrease gastric and intestinal movement Signup and view all the answers

Which condition is a contraindication for the use of cholinergic blocking drugs?

Glaucoma Signup and view all the answers

What is a common adverse reaction associated with cholinergic blocking medications?

Blurred vision Signup and view all the answers

Which drug is used for preanesthetic sedation and motion sickness?

Scopolamine hydrobromide Signup and view all the answers

What may occur as a side effect of higher doses of atropine?

Tachycardia Signup and view all the answers

Which of the following is NOT a use for atropine?

Management of asthma Signup and view all the answers

What is one of the physiological effects of shock on the body?

Decreased cardiac output Signup and view all the answers

Which adrenergic blocking drugs primarily affect the heart?

Beta (β)-adrenergic blocking drugs Signup and view all the answers

What is the result of blocking α-adrenergic fibers?

Vasodilation Signup and view all the answers

Which condition is phentolamine (Regitine) specifically used to treat?

Hypertension caused by pheochromocytoma Signup and view all the answers

What occurs with hypoxia in the context of shock?

Decreased oxygen reaching the cells Signup and view all the answers

What might happen during intravenous administration of norepinephrine if extravasation occurs?

Damaging effects to surrounding tissues Signup and view all the answers

Which group of adrenergic drugs block nerve fibers within the central nervous system?

Antiadrenergic drugs Signup and view all the answers

What results from a decrease in urinary output during shock?

Increased fluid retention in the body Signup and view all the answers

Study Notes

Drugs Acting on ANS

The nervous system regulates and coordinates body functions like movement, digestion, sleep, and waste elimination.
The nervous system has two main divisions: the central nervous system (CNS) and the peripheral nervous system (PNS).
The CNS (brain and spinal cord) receives, integrates, and interprets nerve impulses.
The PNS (nerves outside the brain and spinal cord) connects all body parts to the CNS.

Peripheral Nervous System

The peripheral nervous system includes the somatic nervous system (SNS) and the autonomic nervous system (ANS).
The SNS controls voluntary movement, such as walking, chewing, and writing. Sensory parts of the SNS send messages to the brain regarding internal/external environment (heat, pain, pressure).
The ANS controls involuntary body functions critical for survival. These systems are automatic and not consciously controlled. Blood pressure, heart rate, gastrointestinal activity, and glandular secretions are regulated by the ANS.

Autonomic Nervous System (ANS)

The ANS is divided into the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS).
The sympathetic nervous system (SNS) increases energy expenditure during stressful situations, like danger or illness. It is responsible for speeding up bodily functions like increasing heart rate and diverting energy.
The parasympathetic nervous system (PNS) conserves energy and promotes bodily rest and repair. It's associated with slower bodily functions like decreasing heart rate and promoting digestion.

Neurotransmitters

Neurohormones are chemical substances that facilitate the transmission of nerve impulses at nerve endings.
The two neurohormones in the sympathetic nervous system are epinephrine and norepinephrine. Epinephrine is released by the adrenal medulla, while norepinephrine is primarily released at nerve endings of sympathetic (adrenergic) fibers.
The parasympathetic nervous system uses acetylcholine (ACh) and acetylcholinesterase (AChE) as neurohormones. ACh is responsible for nerve impulse transmission to effector cells in the parasympathetic system. AChE rapidly deactivates ACh, preventing prolonged nerve stimulation.

Cholinergic Drugs

Cholinergic drugs mimic the parasympathetic nervous system's activity.
Direct-acting cholinergics act like ACh, while indirect-acting ones inhibit AChE, prolonging ACh's activity.
Uses include treating glaucoma, myasthenia gravis, and urinary retention. Glaucoma treatment usually involves eye drops. Myasthenia gravis involves skeletal muscle fatigue, often treated with drugs that enhance acetylcholine action. Urinary retention problems can also be addressed with cholinergic drugs.

Adverse Reactions and Precautions

Oral/Parenteral administration of cholinergic drugs can cause nausea, diarrhea, abdominal cramping, salivation, skin flushing, cardiac arrhythmias, and muscle weakness.
Topical application may result in temporary visual acuity reduction and headache.
Cholinergic drugs are contraindicated for those with hypersensitivity to the drugs, asthma, peptic ulcer disease, coronary artery disease, and hyperthyroidism.
Use cautiously in patients with hypertension, epilepsy, cardiac arrhythmias, bradycardia, recent coronary occlusion, or megacolon
Avoid during pregnancy, breastfeeding, and in children, as safety is not fully proven for those groups.

Cholinergic Crisis

A cholinergic crisis is a severe reaction to cholinergic drugs and involves symptoms like abdominal cramping, diarrhea, excessive salivation, muscle weakness, rigidity, spasms, and jaw clenching.
Immediate medical help and an antidote (e.g., atropine) are crucial.

Cholinergic Blocking Drugs

Cholinergic blocking drugs (anticholinergics) inhibit acetylcholine activity, often having the opposite effects of cholinergic drugs.
They affect numerous systems including eyes, respiratory and gastrointestinal tracts, heart and bladder
Examples include atropine, scopolamine, and propantheline.

Actions of Cholinergic Blocking Drugs

Inhibit acetylcholine activity in parasympathetic nerve fibers. This leads to reduced nerve impulse transmission.
Various effects, such as dreamless sleep, drowsiness.
Increased pupil dilation, reduced accommodation.
Decrease in secretions from respiratory tract.
Decreased in stomach secretions and gastrointestinal motility.
Increase in heart rate.
Increased bladder contraction
These effects are due to reduced parasympathetic activity.

Uses of Cholinergic Blocking Drugs

Used to treat conditions such as pylorospasm, peptic ulcer, ureteral and biliary colic, vagally induced bradycardia, Parkinsonism.
Reduced secretions in the upper respiratory tract before general anesthesia.
Used in pre-anesthetic sedation and motion sickness.
Also for certain situations like peptic ulcers.

Adrenergic Drugs

Mimic the effects of the sympathetic nervous system. They're also called sympathomimetic drugs.
Primarily contain epinephrine and norepinephrine, naturally occurring neurohormones.
Synthetic versions are also available in medicine.
Examples include metaraminol (Aramine), isoproterenol (Isuprel), and ephedrine.

Actions of Adrenergic Drugs

General effects include wakefulness, quick reaction to stimuli, reflexes, reduction in stomach/intestinal movement, and increased heart rate.
Effects on the central nervous system (CNS) and peripheral nervous system (PNS) to different extents, modifying various body functions.
Adrenergic nerve fibers have alpha (α) and beta (β) receptors, where drugs act.

Uses of Adrenergic Drugs

Used in hypovolemic and septic shock, moderately severe hypotension.
Control superficial bleeding in surgical or dental procedures.
Bronchial asthma
Cardiac decompensation and arrest.
Allergic reactions (e.g., anaphylaxis)
Heart block, ventricular arrhythmias.
Nasal congestion (topical use). Local anesthetic prolongations.

Adrenergic blocking Drugs

These drugs either block alpha (α), beta (β), or both. This leads to effects on various bodily systems including the cardiovascular system with changes in heart rate and blood pressure.
α-blocking agents can cause vasodilation.
β-blockers can reduce heart rate and workload.

Uses of Adrenergic Blocking Drugs

Treating hypertension
Treating cardiac arrhythmias.
Preventing reinfarction after myocardial infarction.
Migraine headaches and angina pectoris.
Glaucoma (topical use)

Adverse Reactions & Precautions

May lead to nausea, vomiting, headache, and other side effects.
Contraindications vary depending on the drug, often associated with hypersensitivity to certain drugs, including conditions like asthma and coronary artery disease.
Precautions include considerations like pregnancy or renal failure, where their use could be restricted.

Specific Drugs and their Uses

(Specific examples of action, adverse effects, and specific uses of drugs, as shown in the notes, are listed.)

Shock

Inadequate blood flow and oxygen delivery to tissues and vital organs.
Five types: hypovolemic, cardiogenic, septic, obstructive, and neurogenic.

Clinical Manifestations of Shock

Include cool, clammy skin, rapid heartbeat, low blood pressure, and other signs of decreased blood flow and oxygen delivery to peripheral vessels and vital organs.

Antiadrenergic Drugs

Inhibit norepinephrine release or act centrally to decrease sympathetic nervous system activity.
Certain cardiac arrhythmias and hypertension are possible treatment areas.
Adverse effects include dry mouth, drowsiness, anorexia and other symptoms. Avoid use in individuals with active hepatic disease, liver dysfunction or renal conditions due to increased risk.

α-Adrenergic Blocking Drugs

Opposite of typical adrenergic effects, causing vasodilation instead of vasoconstriction.
They are useful in situations like hypertension associated with pheochromocytoma, a tumor that releases excessive catecholamines. Prevents or treats extravasation damage from infiltration during intravenous drug administration.
Certain adverse effects can include weakness, orthostatic hypotension and tachycardia.

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Description

Test your knowledge on the pharmacological effects of adrenergic and cholinergic drugs, their uses, receptor subtypes, and associated adverse effects. This quiz covers key concepts related to cardiovascular actions, metabolic effects, and clinical uses of various drug types.