Module 4 Pharm Vocab

Adrenergic Agonists

Drugs that stimulate adrenergic receptors and mimic sympathetic nervous system activity

• They are also called sympathomimetics

Sympathomimetics

Medications that produce effects similar to the sympathetic nervous system neurotransmitters epinephrine, norepinephrine, and dopamine

Adrenergic Receptors

Receptor sites that respond to the sympathetic neurotransmitters norepinephrine and epinephrine

• Adrenergic medications produce different effects depending on which receptor type they stimulate (alpha and beta)

Alpha-Adrenergic Receptors

Adrenergic receptors divided into alpha1 and alpha2 subtypes

• Alpha1 stimulation commonly produces vasoconstriction and affects smooth muscle in several body systems

Beta-Adrenergic Receptors

Adrenergic receptors that include beta1 and beta2 subtypes

• Beta1 receptors are located primarily in the heart, while beta2 receptors are prominent in bronchial, vascular, and other smooth muscle

Catecholamines

Substances capable of producing a sympathomimetic response

• Epinephrine, norepinephrine, and dopamine are endogenous catecholamines, while some medications act as synthetic catecholamines

Dopaminergic Receptor

A receptor activated by dopamine

• Stimulation can produce vasodilation in selected vascular beds, including vessels supplying the kidneys, heart, brain, and gastrointestinal tract

Positive Inotropic Effect

An increase in the force of myocardial contraction

• Beta1 receptor stimulation can produce this effect and increase stroke volume and cardiac output

Positive Chronotropic Effect

An increase in heart rate

• This effect commonly occurs when beta1 receptors in the heart are stimulated

Positive Dromotropic Effect

An increase in conduction of cardiac electrical impulses through the atrioventricular node

• Beta1 receptor stimulation can increase this conduction along with heart rate and contractility

Adrenergic Blockers

Act as antagonists at alpha or beta receptors

Sympatholytics

Drugs that inhibit sympathetic nervous system activity

• Adrenergic-blocking medications are also called sympatholytics.

First-Dose Phenomenon

A severe and sudden decrease in blood pressure after the first dose of an alpha-adrenergic blocker

• Dizziness, syncope, and falls may occur

Orthostatic Hypotension

A drop in blood pressure when moving to a standing position

• It can cause dizziness, lightheadedness, or syncope and is common with alpha blockers

Extravasation

Leakage of an IV medication from a blood vessel into surrounding tissue

• Extravasated vasopressor can cause intense vasoconstriction and tissue injury

Cardioselective

Describes beta blockers that primarily block beta1 receptors in the heart, reducing heart rate, conduction and contractility

Intrinsic Sympathomimetic Activity

The ability of some beta blockers to block beta receptors while also partially stimulating them

• Acebutolol, penbutolol, and pindolol have this property

Pheochromocytoma

A tumor of the adrenal gland that can secrete large amounts of epinephrine and norepinephrine, producing substantial stimulation and hypertension

Lipophilicity

The tendency of a drug to be attracted to and dissolve in lipid or fat

• Lipophilic beta blockers such as propranolol can more readily enter the central nervous system

Acetylcholine

The primary neurotransmitter of the parasympathetic nervous system

• It binds to cholinergic receptors and produces parasympathetic responses in target tissues

Acetylcholinesterase

The enzyme responsible for breaking down acetylcholine

• Inhibiting this enzyme allows acetylcholine to remain available at receptor sites longer

Cholinergic Receptor

A nerve receptor that is stimulated by acetylcholine

• The two major types are muscarinic and nicotinic receptors

Muscarinic Receptors

Cholinergic receptors located in smooth muscle, cardiac muscle, and glands supplied by parasympathetic fibers

• Many desired effects of cholinergic drugs result from muscarinic receptor stimulation

Nicotinic Receptors

Cholinergic receptors located primarily in the autonomic ganglia where presynaptic and postsynaptic nerve fibers meet

• They can also be stimulated by nicotine

Parasympathomimetics

Drugs that mimic parasympathetic nervous system activity

• The term is used interchangeably with cholinergic drugs and cholinergic agonists

Direct-Acting Cholinergic Agonist

A medication that binds directly to cholinergic receptors and activates them

• Bethanechol and pilocarpine are examples

Cholinesterase Inhibitor

An indirect-acting cholinergic drug that inhibits acetylcholinesterase, increasing the amount of acetylcholine available to stimulate cholinergic receptors

Miosis

Constriction of the pupil

• Cholinergic stimulation can produce miosis, which may help reduce intraocular pressure

Cholinergic Crisis

Severe toxicity caused by excessive acetylcholine activity

• Findings may include: increased secretions, abd cramping, vomiting, diarrhea, hypotension, bradycardia, respiratory compromise, circulatory collapse, and cardiac arrest

Cholinergic-Blocking Drugs

Drugs that block the actions of acetylcholine at receptor sites and reduce parasympathetic nervous system activity

Parasympatholytics

Drugs that reduce parasympathetic nervous system activity

• This is another term for cholinergic-blocking drugs

Anticholinergics

The term most commonly used in clinical practice for drugs that inhibit acetylcholine activity in the parasympathetic nervous system

Antimuscarinic

Describes a drug that blocks acetylcholine at muscarinic receptors

• Cholinergic receptors act primarily at these receptors

Competitive Antagonist

A drug that competes with acetylcholine for a receptor site

• Once the blocker occupies the muscarinic receptor, acetylcholine cannot produce its usual cholinergic response

Mydriasis

Dilation of the pupil

• Blocking cholinergic stimulation prevents contraction of the iris sphincter muscle, allowing the pupil to dilate

Cycloplegia

Paralysis of the ciliary muscle of the eye, which decreases the eye's ability to accommodate for near vision and may contribute to blurred vision

Urinary Retention

Difficulty emptying the bladder

• Anticholinergic activity can relax the detrusor muscle and increase internal sphincter constriction, reducing bladder emptying

Anticholinergic Toxicity

Excessive cholinergic blockade that may produce findings such as tachycardia, hot dry skin, urinary retention, confusion, hallucinations, delirium, and cardiac dysrhythmias

Antacids

Basic compounds that neutralize acid already present in the stomach

• They do not stop the stomach from producing acid

Gastric Hyperacidity

Overproduction of stomach acid

• Persistent hyperacidity can contribute to reflux, mucosal injury, esophagitis, and peptic ulcer disease

Parietal Cells

Stomach cells that produce and secrete hydrochloric acid

• They are a major target of acid-suppressing drug therapy.

Hydrochloric Acid

Acid secreted by parietal cells that maintains the stomach's highly acidic environment and supports digestion and protection against microorganisms

H2 Receptor Antagonists

Acid-suppressing drugs that competitively block H2 receptors on parietal cells, reducing hydrogen ion secretion and increasing gastric pH.

Proton Pump

The hydrogen-potassium ATPase pump in parietal cells

• It performs the final step in moving hydrogen ions into the stomach to form gastric acid

Proton Pump Inhibitors

Drugs that irreversibly inhibit the proton pump, greatly reducing hydrogen ion secretion and gastric acid production.

Mucosal Protectant

A drug that protects damaged GI tissue by forming a local barrier over ulcers or erosions rather than primarily suppressing acid production

Acid Rebound

A return of increased gastric acidity associated with overuse, misuse, or rapid discontinuation of some high acid-neutralizing antacids

Milk-Alkali Syndrome

A complication associated with excessive calcium-containing antacid use, characterized by hypercalcemia, alkalosis, headache, and nausea

Antidiarrheal Drugs

Medications used to counter or control diarrhea.

• Different classes work by binding substances in the GI tract, reducing intestinal motility, decreasing secretions, or restoring normal intestinal flora

Diarrhea

The abnormally frequent passage of loose stools

• Nursing assessment includes the frequency, amount, consistency, associated symptoms, hydration status, and possible cause before medication therapy is selected

Constipation

A condition involving abnormally infrequent or difficult passage of stool

• Possible contributing factors include medications, inadequate fluid or fiber intake, inactivity, metabolic conditions, and neurologic disorders.

Peristalsis

The coordinated wavelike contraction and relaxation of GI smooth muscle that moves intestinal contents through the gastrointestinal tract

• Several bowel medications work by either slowing or increasing this movement.

Irritable Bowel Syndrome (IBS)

A recurring intestinal disorder characterized by abdominal discomfort, bloating, flatulence, diarrhea, constipation, or alternating bowel patterns

• Medication therapy differs depending on whether diarrhea or constipation predominates.

Laxatives

Medications that promote bowel evacuation by increasing stool bulk, softening or lubricating stool, increasing intestinal water, or stimulating peristalsis

Absorbents

A class of antidiarrheal medications that coat the GI tract and bind substances such as bacteria or toxins to their surface so they can be eliminated in the stool

• Because they can also bind medications, drug interactions are an important consideration

Probiotics

Products containing microorganisms that help restore the balance of normal intestinal flora

• They may be useful when normal GI bacteria have been disrupted, such as during antibiotic therapy

Bulk-Forming Laxatives

Laxatives that absorb water and increase the bulk of intestinal contents

• The increased bulk distends the bowel and promotes reflex peristalsis.

• Adequate fluid intake is essential to reduce the risk of obstruction or impaction.

Hyperosmotic Laxatives

Laxatives that increase the water content of the stool, producing intestinal distention, increased peristalsis, and bowel evacuation

• Fluid and electrolyte status are important nursing considerations with this class

Nausea

An unpleasant sensation that often produces the urge to vomit and may precede emesis

Emesis

The forcible emptying of gastric and sometimes intestinal contents through the mouth; another term for vomiting

Antiemetic Drugs

Medications used to prevent or relieve nausea and vomiting

• Different classes act at different points in the vomiting pathways

Chemoreceptor Trigger Zone (CTZ)

A brain region involved in detecting nausea-producing substances and sending signals that help trigger vomiting

Vomiting Center

The brain area responsible for coordinating the physiologic events that produce nausea and vomiting

Anticholinergic Antiemetics

Drugs that block acetylcholine receptors in vestibular and related pathways

• They are especially useful for motion-related nausea and vomiting

Antidopaminergic Antiemetics

Drugs that block dopamine receptors in the CTZ

• Their safety profile includes risks such as orthostatic hypotension and extrapyramidal symptoms.

Prokinetic Drugs

Medications that increase GI motility and promote gastric emptying

• Some also reduce nausea by blocking dopamine receptors in the CTZ

5-HT3 Receptor Blockers

Serotonin-blocking antiemetics that act at 5-HT3 receptors in the GI tract, CTZ, and vomiting center

• They are commonly used for chemotherapy- and postoperative-related nausea and vomiting

Neurokinin-1 Antagonists

Antiemetics that block substance P at neurokinin-1 receptors in the brain stem

• They are often combined with other antiemetic classes for chemotherapy-induced nausea and vomiting