⚡ Module 7 · Autonomic Nervous System

12 drugs · 9 concepts · tested on Exam 4

💡 The big idea

This is the module that makes half of pharmacology make sense. Everything reduces to one 2x2: sympathetic (fight or flight) vs parasympathetic (rest and digest), crossed with agonist (turn it on) vs antagonist (turn it off). Once you know which receptor a drug hits — alpha-1, alpha-2, beta-1, beta-2, muscarinic, nicotinic — the therapeutic effects and the adverse effects are the same everywhere in the body.

🧠 How to think about this module

Learn the receptors, not the drugs. Alpha-1 = squeeze vessels (BP up, pupil dilates, bladder neck tightens). Beta-1 = heart (rate and force up). Beta-2 = lungs and uterus (relax). Muscarinic = rest and digest (slow the heart, wet the secretions, empty the bladder and bowel).
'One heart, two lungs' — beta-1 is in the one heart, beta-2 is in the two lungs.
Blocking a receptor gives exactly the opposite of stimulating it. Learn the agonist and you get the blocker for free.
Cholinergic = wet. Anticholinergic = dry. That one line answers most adverse-effect questions in this module.
For vasopressors, ask what the shock needs: pure squeeze (phenylephrine, vasopressin), squeeze plus heart (norepinephrine), or everything including bronchodilation (epinephrine).

🏷️ The whole module in 9 classes

Learn these groups and the drug list stops being 12 separate names.

Class	What it does	Examples	What gets tested
Alpha-1 agonists	Constrict blood vessels: BP up, nasal mucosa dries, pupil dilates.	phenylephrine, pseudoephedrine, midodrine, norepinephrine (partly)	Reflex bradycardia and hypertension. IV vasoconstrictors cause tissue necrosis if they extravasate — check the site at least hourly; phentolamine is the antidote. Oral decongestants are contraindicated in uncontrolled hypertension.
Alpha-1 blockers	Relax vascular smooth muscle and the bladder neck.	prazosin, doxazosin, terazosin, tamsulosin	First-dose phenomenon — severe orthostatic hypotension and syncope with the first dose. Give the first dose at bedtime and teach the client to sit on the edge of the bed before standing.
Central alpha-2 agonists	Tell the brain to send LESS sympathetic outflow, so BP falls.	clonidine, methyldopa, dexmedetomidine	Never stop clonidine abruptly — severe rebound hypertension. Taper it. Sedation and dry mouth are expected; methyldopa is the classic safe antihypertensive in pregnancy.
Beta-1 agonists and catecholamines	Speed and strengthen the heart; used in shock and cardiac arrest.	dobutamine, dopamine, epinephrine, norepinephrine, isoproterenol	Continuous cardiac monitoring and an arterial line; central access preferred. Titrate to MAP or blood pressure per protocol. Tachyarrhythmias and increased myocardial oxygen demand are the limiting effects.
Beta blockers	Slow the heart, lower BP, reduce myocardial oxygen demand.	metoprolol, atenolol, bisoprolol, esmolol (beta-1 selective); propranolol, nadolol, sotalol, timolol, carvedilol, labetalol (non-selective)	Assess the apical pulse for a full minute before giving. If it is under 60, withhold the dose and call the provider unless other parameters were ordered. Non-selective agents cause bronchospasm in asthma and mask the tachycardia of hypoglycemia in diabetes.
Beta-2 agonists	Relax bronchial and uterine smooth muscle.	albuterol, levalbuterol (short-acting); salmeterol, formoterol (long-acting); terbutaline	Tachycardia, tremor, nervousness, and hypokalemia. Needing a rescue inhaler more than 2 days a week means the control regimen has failed. Long-acting beta agonists are never rescue drugs.
Cholinergics (muscarinic agonists and cholinesterase inhibitors)	Raise acetylcholine: wet everything, empty the bladder and bowel, strengthen weak muscle.	bethanechol (urinary retention), pilocarpine (glaucoma); neostigmine, pyridostigmine, edrophonium, donepezil	Cholinergic crisis is the overdose picture — SLUDGE plus bradycardia, bronchospasm, and increasing muscle weakness. Atropine is the antidote. Support the airway first.
Anticholinergics (muscarinic antagonists)	Dry everything, speed the heart, relax the bladder and bronchi.	atropine, ipratropium, oxybutynin, scopolamine, benztropine, glycopyrrolate, diphenhydramine	Urinary retention, constipation, blurred vision, dry mouth, heat intolerance, and confusion. Especially dangerous in older adults and contraindicated in narrow-angle glaucoma and significant BPH.
Neuromuscular blockers	Paralyze skeletal muscle at the nicotinic junction for intubation and surgery.	succinylcholine (depolarizing); rocuronium, vecuronium, cisatracurium (non-depolarizing)	These provide NO sedation and NO analgesia. A paralyzed client must also be sedated and treated for pain — they can hear and feel everything. Succinylcholine causes hyperkalemia and can trigger malignant hyperthermia.

⚖️ Depolarizing vs non-depolarizing neuromuscular blockers

Succinylcholine (depolarizing)	Rocuronium / vecuronium (non-depolarizing)
Holds the receptor channel open — fasciculations first, then paralysis	Competitively blocks the receptor — no fasciculations
Onset roughly 30-60 seconds, duration about 5-10 minutes — the intubation drug	Slower onset, duration 30 minutes or more — the maintenance drug
No reversal agent; you wait for it to wear off	Reversed by neostigmine with glycopyrrolate, or by sugammadex
Causes hyperkalemia; can trigger malignant hyperthermia	No malignant hyperthermia risk
Avoid in burns, crush injury, and neuromuscular disease (lethal potassium release)	Preferred when succinylcholine is contraindicated

🚨 Red flags DANGER

Malignant hyperthermia after succinylcholine or a volatile anesthetic: rigid jaw, rising end-tidal CO2, then a soaring temperature. Stop the trigger, give dantrolene 2.5 mg/kg IV, and cool aggressively. Temperature rise is a LATE sign — do not wait for it.
Cholinergic crisis: SLUDGE plus bradycardia, wheezing, and worsening weakness. Secure the airway and give atropine. Do NOT give more pyridostigmine.
Anaphylaxis: epinephrine 0.3 mg IM (1 mg/mL concentration) into the outer thigh for an adult, repeated every 5 to 15 minutes as needed. IM thigh — not subcutaneous, not the deltoid.
Never stop clonidine or a beta blocker abruptly. Rebound hypertension and rebound tachycardia with ischemia can follow within 24 to 48 hours.
Beta blocker with an apical pulse under 60 or a systolic BP below the ordered parameter: hold and call. Charting it is not enough.

🧵 Exam traps ⭐ HIGH YIELD

Beta-1 'selective' drugs lose selectivity at high doses. Metoprolol can still cause bronchospasm in an asthmatic at a high dose.
SLUDGE describes CHOLINERGIC excess — the wet picture. Her textbook prints SLUDGE under anticholinergics with the effects reversed (decreased salivation, decreased lacrimation). Decide from the drug in the stem, not from the mnemonic.
Atropine treats CHOLINERGIC crisis, not myasthenic crisis. Both look like weakness, but myasthenic crisis needs MORE cholinesterase inhibitor plus airway support. Edrophonium was historically used to tell them apart.
Epinephrine and norepinephrine are not interchangeable. Norepinephrine is mostly alpha (squeeze); epinephrine adds beta-2 bronchodilation, which is why anaphylaxis specifically gets epinephrine.
Terbutaline is a beta-2 agonist used off-label to slow preterm labor, but the FDA warns against prolonged use beyond 48 to 72 hours because of maternal cardiac events.
'-olol' almost always means beta blocker, but timolol EYE DROPS are absorbed systemically and still cause bradycardia and bronchospasm.

🧠 Ways to remember it

One heart, two lungs: beta-1 in the heart, beta-2 in the lungs.
Cholinergic = wet (SLUDGE: Salivation, Lacrimation, Urination, Defecation, GI upset, Emesis).
Anticholinergic = hot as a hare, dry as a bone, red as a beet, blind as a bat, mad as a hatter.
Alpha = Arteries (squeeze). Beta = Beats and Breathe.
'Sux is quick and short' — succinylcholine in fast, out fast. And prazosin: 'first dose, floor drop' — give it at bedtime.

🧠 The concepts 9

What are the adverse effects of beta-blockers?⭐ HIGH YIELD

Bradycardia and hypotension are the big ones. Also fatigue, dizziness, bronchospasm (non-selective agents in asthma or COPD), MASKED HYPOGLYCEMIA symptoms, erectile dysfunction, depression and vivid dreams, and worsening of acute decompensated heart failure. NEVER stop a beta blocker abruptly: rebound tachycardia, hypertension, angina, and MI.

Hold the dose and call the provider for an apical heart rate under 60 or systolic BP under 90 (or per ordered parameters). Take an APICAL pulse for a full minute.
Cardioselective (beta-1) agents are safer in lung disease: metoprolol, atenolol, bisoprolol, esmolol. A through M tend to be beta-1 selective.
Non-selective (beta-1 and beta-2): propranolol, nadolol, sotalol, timolol, labetalol, carvedilol. These carry bronchoconstriction risk.
In diabetes, beta blockers mask the tachycardia, tremor, and palpitations of hypoglycemia. DIAPHORESIS still occurs and becomes the key warning sign.
Teach: change positions slowly, never skip doses, and report weight gain over 2 to 3 lb in a day, new edema, or shortness of breath. Uses: hypertension, angina, post-MI, stable heart failure (carvedilol, metoprolol succinate, bisoprolol, titrated slowly), migraine prophylaxis, performance anxiety, and glaucoma (timolol drops).

Beta blockers SLOW the heart, MASK the low sugar, TIGHTEN the airway, and are never stopped cold.

What medications can be administered to increase blood pressure?⭐ HIGH YIELD

Vasopressors and inotropes: norepinephrine (first-line in septic shock), epinephrine, phenylephrine, dopamine, vasopressin, dobutamine (an inotrope), and oral midodrine for chronic orthostatic hypotension.

Give through a CENTRAL line whenever possible. Extravasation of norepinephrine or dopamine causes tissue necrosis, and the antidote is phentolamine infiltrated locally.
Titrate to a MAP goal, commonly 65 mmHg or higher, with continuous BP monitoring and ideally an arterial line.
Fix the volume first. Pressors on an empty tank just squeeze harder on nothing.
Never bolus or abruptly stop a vasopressor drip; wean gradually.
Midodrine is an oral alpha-1 agonist for chronic orthostatic hypotension. Do not take it within 4 hours of lying down because of supine hypertension.

Drug	Main action	Best use
Norepinephrine (Levophed)	Strong alpha-1 vasoconstriction plus some beta-1	First-line for septic and most distributive shock
Epinephrine	Alpha-1, beta-1, and beta-2	Anaphylaxis, cardiac arrest, refractory shock
Phenylephrine	Pure alpha-1 vasoconstriction	Raises BP without increasing heart rate; useful with tachyarrhythmia
Dopamine	Dose-dependent: dopaminergic, then beta-1, then alpha-1	Bradycardia with hypotension; causes more arrhythmias than norepinephrine
Vasopressin	V1 receptor, non-adrenergic vasoconstriction	Add-on to norepinephrine in septic shock
Dobutamine	Beta-1 inotrope; can LOWER blood pressure	Cardiogenic shock and low cardiac output: increases contractility

Fluids first, then squeeze. Norepinephrine is first-line in septic shock.

What are the signs and symptoms of cholinergic overdose/crisis?🚨 DANGER

Cholinergic crisis is an excess of acetylcholine. Think SLUDGE plus the killer B's: Salivation, Lacrimation, Urination, Defecation and diarrhea, GI cramping, Emesis, plus Bradycardia, Bronchorrhea, and Bronchospasm. The secretions and respiratory muscle weakness are what kill.

Also: MIOSIS (pinpoint pupils), diaphoresis, muscle fasciculations followed by weakness and paralysis, blurred vision, hypotension, confusion, and seizures.
Causes: overdose of cholinesterase inhibitors (neostigmine, pyridostigmine, donepezil), organophosphate or pesticide exposure, nerve agents, and certain mushrooms.
Death comes from respiratory failure: secretions plus bronchospasm plus a paralyzed diaphragm.
DUMBELS is the same list: Diarrhea/Diaphoresis, Urination, Miosis, Bradycardia/Bronchospasm/Bronchorrhea, Emesis, Lacrimation, Salivation.
Distinguish from myasthenic crisis (too LITTLE acetylcholine). Both cause weakness, but only cholinergic crisis has the wet SLUDGE picture and pinpoint pupils.

SLUDGE plus the killer B's. Everything that can leak, leaks.

What are the pharmacological treatment options for cholinergic overdose/crisis?🚨 DANGER

ATROPINE is the antidote: an anticholinergic that dries secretions and reverses bradycardia. For organophosphate or nerve-agent poisoning, add PRALIDOXIME (2-PAM) to reactivate acetylcholinesterase, plus benzodiazepines for seizures and aggressive airway support.

The priority is always the AIRWAY: suction, oxygen, and readiness to intubate. Respiratory failure kills, not the bradycardia.
Atropine is titrated to DRYING of pulmonary secretions and adequate oxygenation, not to heart rate. Repeated and escalating doses are often needed.
Pralidoxime must be given early, before the enzyme 'ages' and the bond becomes permanent, and always WITH atropine rather than instead of it.
Stop the offending cholinesterase inhibitor. For organophosphate exposure, decontaminate skin and clothing while wearing PPE to protect yourself.
Atropine does not reverse the nicotinic effects (fasciculations and muscle weakness). Pralidoxime does.

Atropine DRIES the flood; pralidoxime UNSTICKS the enzyme.

What adverse effects are associated with anticholinergic medications?⭐ HIGH YIELD

Anticholinergics block acetylcholine at muscarinic receptors, producing dry mouth, blurred vision and photophobia from mydriasis, constipation, urinary retention, tachycardia, decreased sweating with hyperthermia, and confusion or delirium, especially in older adults.

Classic mnemonic: can't see, can't pee, can't spit, can't poop, plus hot, red, and mad.
High risk or contraindicated in narrow-angle glaucoma (can precipitate an acute attack), BPH and urinary retention, GI obstruction or paralytic ileus, myasthenia gravis, and dementia.
Drug groups: atropine, scopolamine, benztropine, oxybutynin and tolterodine, ipratropium and tiotropium, first-generation antihistamines (diphenhydramine, hydroxyzine), TCAs, antipsychotics, dicyclomine.
Anticholinergic BURDEN adds up across many drugs and is a top cause of delirium and falls in older adults (Beers criteria).
Teach: sugar-free candy or gum and frequent sips for dry mouth, fiber and fluids for constipation, sunglasses for photophobia, and avoid overheating in hot weather or during exercise.

Blind as a bat, dry as a bone, red as a beet, hot as a hare, mad as a hatter, and full as a flask.

What causes malignant hyperthermia?🚨 DANGER

Malignant hyperthermia is a genetic (autosomal dominant, usually an RYR1 ryanodine receptor mutation) hypermetabolic reaction triggered by VOLATILE INHALED ANESTHETICS (halothane, sevoflurane, desflurane, isoflurane) and the depolarizing paralytic SUCCINYLCHOLINE. Uncontrolled calcium release from the sarcoplasmic reticulum causes sustained muscle contraction.

EARLIEST signs: rising end-tidal CO2, masseter (jaw) rigidity after succinylcholine, unexplained tachycardia, and generalized muscle rigidity. HIGH FEVER IS A LATE SIGN, so do not wait for it.
Later: hyperkalemia, mixed metabolic and respiratory acidosis, rhabdomyolysis with cola-colored urine, arrhythmias, DIC, and renal failure.
Treatment: STOP the trigger, 100% oxygen at high flow, DANTROLENE 2.5 mg/kg IV rapidly and repeated as needed, active cooling, treat hyperkalemia and arrhythmias, and monitor for rhabdomyolysis.
Safe alternatives: propofol, ketamine, opioids, benzodiazepines, nitrous oxide, local and regional anesthesia, and non-depolarizing blockers such as rocuronium.
Keep a stocked MH cart available. Document the reaction and inform all blood relatives, since it is autosomal dominant.

Dantrolene DAMPENS the calcium. Fever is the LAST sign; the CO2 rises first.

Compare depolarizing and non-depolarizing neuromuscular blockers.🚨 DANGER

Depolarizing blockers (succinylcholine) act as acetylcholine AGONISTS: they depolarize the motor end plate, cause fasciculations, then sustained paralysis, and there is NO reversal agent. Non-depolarizing blockers (the -curium and -uronium drugs) are competitive ACh ANTAGONISTS: no fasciculations, longer acting, and reversible with neostigmine or sugammadex.

NEITHER drug provides sedation, amnesia, or analgesia. A paralyzed patient can be fully awake and terrified, so always pair with sedation and pain control.
Succinylcholine is contraindicated in burns more than 24 hours old, crush injury, spinal cord injury or paralysis, prolonged immobility, and known MH risk. All of these cause life-threatening hyperkalemia.
Never give a paralytic without the equipment and skill to ventilate. Airway first, always.
Monitor depth of blockade with train-of-four peripheral nerve stimulation.

Depolarizing (succinylcholine)	Non-depolarizing (rocuronium, vecuronium, cisatracurium)
Agonist that persistently depolarizes the end plate	Competitive antagonist that blocks ACh from binding
Muscle fasciculations first, then paralysis	No fasciculations, smooth onset of paralysis
Ultra-short, about 5 to 10 minutes; broken down by plasma pseudocholinesterase	Intermediate to long acting; renal and hepatic elimination
NO reversal agent, you must wait it out	Reversed by neostigmine with glycopyrrolate, or sugammadex for rocuronium and vecuronium
Used for rapid sequence intubation	Used for maintenance of surgical paralysis and in ventilated patients
Risks: malignant hyperthermia, HYPERKALEMIA, bradycardia, raised ICP and IOP, postop myalgias	Risks: prolonged paralysis, histamine release with older agents, residual weakness

SUX = short, sudden, no antidote. The '-uroniums' you can reverse.

What are the pharmacological treatment options for myasthenia gravis?⭐ HIGH YIELD

First-line is a cholinesterase inhibitor, PYRIDOSTIGMINE (Mestinon), which increases available acetylcholine at the neuromuscular junction. Add immunosuppression (corticosteroids, azathioprine, mycophenolate); for crisis use PLASMAPHERESIS or IVIG; thymectomy is used in selected patients.

Give pyridostigmine ON TIME, usually 30 to 60 minutes BEFORE meals, so the patient has the strength to chew and swallow.
Newer targeted agents: eculizumab and ravulizumab (complement inhibitors), efgartigimod and rozanolixizumab (FcRn blockers) for refractory disease.
AVOID drugs that worsen myasthenia gravis: aminoglycosides, fluoroquinolones, macrolides, beta blockers, magnesium, neuromuscular blockers, and procainamide or quinidine.
Myasthenic crisis is too LITTLE acetylcholine (weakness plus respiratory failure): treat with more cholinesterase inhibitor plus plasmapheresis or IVIG. Cholinergic crisis is too MUCH: hold the drug and give atropine.
Both crises cause respiratory failure. Bedside vital capacity and negative inspiratory force guide the decision to intubate.

Pyridostigmine 30 to 60 minutes before meals: strength for the fork.

Edrophonium⭐ HIGH YIELD

Edrophonium (Tensilon) is an ultra-SHORT-acting cholinesterase inhibitor used diagnostically, in the 'Tensilon test,' to distinguish myasthenic crisis from cholinergic crisis. Strength IMPROVES = myasthenic crisis (too little ACh). Weakness WORSENS with SLUDGE symptoms = cholinergic crisis (too much ACh).

Onset in about 30 to 60 seconds with effects lasting only 5 to 10 minutes: too short to treat with, perfect for a test.
Have ATROPINE at the bedside as the antidote before giving it, plus emergency airway and resuscitation equipment.
Risks: bradycardia, hypotension, bronchospasm, increased secretions, and asystole.
Edrophonium has largely been discontinued in the US and replaced by antibody testing, ice-pack testing, and repetitive nerve stimulation, but it is still tested on nursing exams.
Do not confuse it with pyridostigmine (long-acting, for treatment) or neostigmine (intermediate, used to reverse non-depolarizing blockers).

Edrophonium is the QUESTION, not the treatment: better means myasthenic, worse means cholinergic. Atropine at the bedside.

💉 The drugs 12

💉 Albuterol

Bronchodilator, Adrenergic β2-agonist, sympathomimetic, bronchodilator

What it is for

Prevention of exercise-induced asthma, acute bronchospasm, bronchitis, emphysema, bronchiectasis, or other reversible airway obstruction Unlabeled: Hyperkalemia in dialysis patients, COPD, emphysema

How it works

Causes bronchodilation by action on β2 (pulmonary) receptors by increasing levels of cAMP

Watch for

CNS Tremors, anxiety, insomnia, headache, stimulation, restlessness
CV Angina, hypo/hypertension, dysrhythmias, chest pain
EENT Dry nose, irritation of nose and throat
GI Nausea, vomiting
MISC Hyperglycemia
RESP Paradoxical bronchospasm

Teaching

To use exactly as prescribed; to take missed dose when remembered, alter dosing schedule; not to use OTC medications; that excess stimulation may occur, to use this produ …
About use of inhaler: review package insert with patient; use demonstration, return demonstration; shake, prime before first use and when not used for >2 wk; release 4 te …
To avoid getting aerosol in eyes (blurring of vision may result) or use near flames or sources of heat
Do not wash inhaler, wipe with dry cloth, to discard product when counter changes to red

🔗 Full card in the drug guide

💉 ClonidineBLACK BOX

Antihypertensive, Central alpha-adrenergic agonist

What it is for

Mild to moderate hypertension, used alone or in combination; severe pain in cancer patients (epidural), attention-deficit/hyperactivity disorder (ADHD)

How it works

Inhibits sympathetic vasomotor center in CNS, which reduces impulses in sympathetic nervous system; B/P, pulse rate, cardiac output are decreased …

Watch for

CNS Drowsiness, nightmares, anxiety, depression, hallucinations, syncope, dizziness
CV Orthostatic hypotension, HF, ECG abnormalities, sinus tachycardia
EENT Taste change, dry eyes
ENDO Hyperglycemia
GI Nausea, vomiting, constipation, dry mouth
GU Impotence, urinary retention …

Teaching

To avoid hazardous activities and driving until response is known, product may cause drowsiness
To notify all health care providers of medication use
Not to discontinue product abruptly or withdrawal symptoms may occur: anxiety, increased B/P, headache, insomnia, increased pulse, tremors, nausea, sweating; to comply wi …
Not to use OTC (cough, cold, or allergy), alcohol, or CNS depressant products unless directed by prescriber

Antidote / reversal: 1

🔗 Full card in the drug guide

💉 EpinephrineHIGH ALERT

Bronchodilator nonselective adrenergic agonist, vasopressor, Catecholamine

What it is for

Acute asthmatic attacks, hemostasis, bronchospasm, anaphylaxis, allergic reactions, cardiac arrest, adjunct in anesthesia, shock

How it works

β1- and β2-agonist causing increased levels of cAMP, thereby producing bronchodilation, cardiac, and CNS stimulation; high doses cause vasoconstriction via alpha-receptors; low doses can cause vasodilation via β2-vascular receptors

Watch for

CNS Tremors, anxiety, insomnia, headache, dizziness, confusion, hallucinations, weakness, drowsiness
CV Palpitations, tachycardia, hypertension, dysrhythmias, increased T wave
GI Anorexia, nausea, vomiting
MISC Sweating, dry eyes
RESP Dyspnea …

Teaching

About the reason for product administration
Inhalation: to rinse mouth after use to prevent dryness after inhalation, not to spray near eyes, teach correct use
To take exactly as prescribed. If on scheduled regimen, take missed dose as soon as remembered. Space remaining doses evenly. Do not double doses. To contact prescriber i …
To consult prescriber prior to taking any OTC, Rx medications, supplements or herbals

🔗 Full card in the drug guide

💉 MetoprololHIGH ALERTBLACK BOX

Antihypertensive, antianginal, β1-Blocker

What it is for

Mild to moderate hypertension, acute MI to reduce cardiovascular mortality, angina pectoris, NYHA class II, III heart failure, cardiomyopathy

How it works

Lowers B/P by β-blocking effects; reduces elevated renin plasma levels; blocks β2-adrenergic receptors in bronchial, vascular smooth muscle only at high doses; negative chronotropic effect

Watch for

CNS Insomnia, dizziness, mental changes, hallucinations, depression, anxiety, headaches, nightmares, confusion, fatigue, weakness
CV Hypotension, bradycardia, HF, palpitations, dysrhythmias, cardiac arrest, AV block, pulmonary/peripheral edema, chest pain
EENT Blurred vision
GI Nausea …

Teaching

To take immediately after meals; to take medication at bedtime to prevent effect of orthostatic hypotension

Antidote / reversal: 1

🔗 Full card in the drug guide

💉 NorepinephrineHIGH ALERT

Vasopressor, α/ β-agonist

What it is for

Acute hypotension, shock

How it works

Causes increased contractility and heart rate by acting on β-receptors in heart; also acts on α-receptors, thereby causing vasoconstriction in blood vessels; B/P is elevated, coronary blood flow improves, and cardiac output increases

Watch for

CNS Headache, anxiety, dizziness, insomnia, restlessness, tremor, cerebral hemorrhage
CV Palpitations, tachycardia, hypertension, ectopic beats, angina
GI Nausea, vomiting
GU Decreased urine output
INTEG Necrosis, tissue sloughing with extravasation, gangrene
RESP Dyspnea
SYST Anaphylaxis

Teaching

About the reason for product administration; to report dyspnea, dizziness, chest pain

🔗 Full card in the drug guide

💉 Phenylephrine/pseudoephedrineHIGH ALERT

Vasopressor, nasal decongestant, mydriatic, Alpha-1 adrenergic agonist

What it is for

Clinically important hypotension from vasodilation, especially under anesthesia (IV); nasal congestion (spray); pupil dilation for eye exams (ophthalmic); hemorrhoids (topical). The oral form is sold for congestion but FDA has proposed removing it as ineffective.

How it works

An alpha-1 agonist with minimal to no beta activity. It squeezes blood vessels; it does not directly drive the heart. Pressure rises because the vessels tighten, and the vagus answers that rise by SLOWING the heart.

Watch for

CV Reflex BRADYCARDIA, hypertension, reduced cardiac output, reduced blood flow to kidney and gut, arrhythmias.
CNS Headache, restlessness, tremor, insomnia.
EENT Rebound congestion after more than three days of spray

Teaching

Pure enough alpha-1 that the exam point is simple: vessels constrict, pressure goes UP, and the heart rate reflexively goes DOWN. Reflex bradycardia is the classic answer.
IV it is a high-alert vasopressor and a vesicant. Watch the site continuously. If it infiltrates: stop the infusion, leave the catheter in to aspirate, then infiltrate the area with about 5 to 10 mg of phentolamine in 10 mL of saline, within 12 hours.
The ORAL form does not work. FDA proposed removing oral phenylephrine in November 2024 because first-pass metabolism destroys it before it reaches the nose. It is still on shelves because the order is not final. The NASAL SPRAY does work.
Do not confuse it with pseudoephedrine. Pseudoephedrine is the effective one, kept behind the pharmacy counter; phenylephrine sits out on the open shelf.

Antidote / reversal: 1

🔗 Full card in the drug guide

💉 Prazosin

Antihypertensive, α1-Adrenergic blocker, peripheral

What it is for

Hypertension, benign prostatic hypertrophy to decrease urine outflow obstruction

How it works

Blocks α-mediated vasoconstriction of adrenergic receptors, thereby inducing peripheral vasodilation

Watch for

CNS Dizziness, headache, drowsiness, anxiety, depression, vertigo, weakness, fatigue, syncope
CV Palpitations, orthostatic hypotension, tachycardia, edema, rebound hypertension
EENT Blurred vision, epistaxis, tinnitus, dry mouth, red sclera
GI Nausea, vomiting, diarrhea, constipation …

Teaching

That fainting occasionally occurs after 1st dose; to take 1st dose at bedtime; not to drive or operate machinery for 4 hr after 1st dose; that full effect may take 4-6 wk
To change positions slowly to prevent orthostatic hypotension
To avoid OTC medications, alcohol unless approved by prescriber; not to crush, chew caps
Not to discontinue abruptly

🔗 Full card in the drug guide

💉 TerbutalineBLACK BOX

Selective β2-agonist; bronchodilator, Catecholamine

What it is for

Bronchospasm Unlabeled: Premature labor

How it works

Relaxes bronchial smooth muscle by direct action on β2-adrenergic receptors through the accumulation of cAMP at β-adrenergic receptor sites; bronchodilation, diuresis, CNS, cardiac stimulation occur; relaxes uterine smooth muscle

Watch for

CNS Tremors, anxiety, insomnia, headache, dizziness, stimulation, restlessness
CV Palpitations, tachycardia, hypertension, dysrhythmias, cardiac arrest, QT prolongation
GI Nausea, vomiting
META Hypokalemia, hyperglycemia
RESP Paradoxical bronchospasm …

Teaching

Avoid cough/cold/allergy OTC medications because extra stimulation may occur
About all aspects of product; to avoid smoking, smoke-filled rooms, persons with respiratory infections
To maintain adequate hydration; to allow 15 min between inhalation of product and inhaled product containing steroid
To take on time; if missed, not to make up after 1 hr; to wait until next dose

🔗 Full card in the drug guide

💉 AtropineHIGH ALERT

Antidysrhythmic, anticholinergic parasympatholytic, antimuscarinic, Belladonna alkaloid

What it is for

Bradycardia <40-50 bpm, bradydysrhythmia, reversal of anticholinesterase agents, insecticide poisoning, blocking cardiac vagal reflexes, decreasing secretions before surgery, antispasmodic with GU, biliary surgery, bronchodilator …

How it works

Blocks acetylcholine at parasympathetic neuroeffector sites; increases cardiac output, heart rate by blocking vagal stimulation in heart; dries secretions by blocking vagus

Watch for

CNS Headache, dizziness, involuntary movement, confusion, flushing, drowsiness
CV Tachycardia, bradycardia
EENT Blurred vision, photophobia, dry eyes
GI Dry mouth, constipation
RESP Tachypnea, pulmonary edema
GU Retention, hesitancy, impotence
INTEG Flushing, decreased sweating

Teaching

To report blurred vision, chest pain, allergic reactions, constipation, urinary retention; to use sunglasses to protect the eyes
Not to perform strenuous activity in high temperatures; heat stroke may result
To take as prescribed; not to skip or double doses
Not to operate machinery if drowsiness occurs

Antidote / reversal: 1

🔗 Full card in the drug guide

💉 Bethanechol

Urinary tract stimulant, cholinergic, Synthetic choline ester

What it is for

Urinary retention (postoperative, postpartum), neurogenic atony of bladder with retention Unlabeled: Ileus, GERD, anticholinergic syndrome

How it works

Stimulates muscarinic ACH receptors directly; mimics effects of parasympathetic nervous system stimulation; stimulates gastric motility, micturition; increases lower esophageal sphincter pressure

Watch for

CNS Dizziness, headache, malaise
CV Hypotension, bradycardia, reflex tachycardia, cardiac arrest, circulatory collapse
EENT Miosis, increased salivation, lacrimation, blurred vision
GI Nausea, bloody diarrhea, belching, vomiting, cramps, fecal incontinence
GU Urgency
INTEG Rash, urticaria …

Teaching

To take product exactly as prescribed; 1 hr before meals or 2 hr after meals to avoid nausea
To make position changes slowly; orthostatic hypotension may occur
To avoid driving, hazardous activities until effects are known

🔗 Full card in the drug guide

💉 Oxybutynin

Anticholinergic, urinary antispasmodic, Synthetic tertiary amine

What it is for

Antispasmodic for neurogenic bladder, overactive bladder in females (OTC)

How it works

Relaxes smooth muscles in urinary tract by inhibiting acetylcholine at postganglionic sites

Watch for

CNS Anxiety, restlessness, dizziness, somnolence, insomnia, nervousness, seizures, headache, drowsiness, confusion
CV Palpitations, sinus tachycardia, hypertension, peripheral edema, QT prolongation
EENT Blurred vision, dry eyes, increased intraocular tension, dry mouth, dry throat
GI Nausea …

Teaching

To avoid hazardous activities because dizziness, blurred vision may occur
To avoid OTC medications with alcohol, other CNS depressants
To avoid hot weather, strenuous activity because product decreases perspiration
About the correct application of each product form

🔗 Full card in the drug guide

💉 Succinylcholine (How does the duration of action compare to other neuromuscular blockers?)HIGH ALERTBLACK BOX

Neuromuscular blocker (depolarizing, ultra short)

What it is for

Facilitation of endotracheal intubation, skeletal muscle relaxation during orthopedic manipulations

How it works

Inhibits transmission of nerve impulses by binding with cholinergic receptor sites, thus antagonizing action of acetylcholine; causes release of histamine

Watch for

CV Bradycardia, tachycardia; increased, decreased B/P; sinus arrest, dysrhythmias, edema
EENT Increased secretions, intraocular pressure
HEMA Myoglobulinemia
INTEG Rash, flushing, pruritus, urticaria
MS Weakness, muscle pain, fasciculations, prolonged relaxation, myalgia …

Teaching

Reason for product, expected results

🔗 Full card in the drug guide

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Where this came from. The drug cards come from your own drug guide, fact-checked against FDA labeling. The explanations were written from your course textbook, Pharmacology (WTCS, 2e). If anything here contradicts your instructor, believe your instructor — they write the exam.

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