Cholinergics & Adrenergics

Parasympathetic Response

• decreases HR, BP

• increases salivation, peristalsis

• constricts bladder, pupils, bronchioles

• dilates blood vessels

Sympathetic Response

• increases HR and BP

• decreases salivation, peristalsis

• dilates pupils, bronchioles

• relaxes smooth muscle and bladder muscles

• constricts blood vessels

Adrenergic Drugs

• aka sympathomimetic drugs that mimic the effects of the sympathetic nervous system, increasing HR, BP, and RR, dilating bronchioles, and mobilizing energy.

• also increases release of NE and EPI

• used to treat asthma, cardiac arrest, and hypotension.

Adrenergic Antagonist

• aka sympatholytic drugs

• that block the effects of the sympathetic nervous system, decreasing heart rate and blood pressure, and causing bronchoconstriction.

• inhibits release of NE

• and are used to treat conditions such as hypertension, anxiety, and certain heart conditions.

Cholinergic Drugs 

• aka parasympathomimetic drugs

• that mimic the actions of the parasympathetic nervous system, promoting functions such as decreased heart rate, increased salivation and digestion, bladder and pupillary constricts

• increasing release of AcH & muscarine

• typically end in -chol

• and are used to treat conditions like glaucoma and myasthenia gravis.

Cholinergic Antagonist

• aka parasympatholytic drugs 

• that block the effects of the parasympathetic nervous system, leading to increased heart rate, decreased salivation and digestion and relaxation of smooth muscles.

• Also inhibits release of AcH.

• Anticholinergic = “can’t see, can’t pee, can’t spit, can’t poop

• They are used to treat conditions such as asthma, motion sickness, and overactive bladder.

nicotinic receptors

• works with ACh to contract skeletal muscles leading to release of adrenaline 

• are fast acting leading to slowing down of HR, BP, and GI system increases 

muscuranic receptors

• works on smooth muscles

• CNS: memory , arousal, attention, analgesia

• Heart: conduction at the SA and AV nodes

• they mediate various parasympathetic responses including decreased heart rate and increased glandular secretions.

Bethanechol 

• cholinergic agonist (direct-acting muscuranic) used for urinary retention and gastrointestinal motility enhancement.

• MOA: stimulates muscarinic receptors, increasing bladder contraction and promoting gastrointestinal activity.

• SE: SLUDGE

Bethanechol patient teaching 

• Take medication on an empty stomach (1 hr before or 2 hr after meals) to reduce nausea/vomiting.

• Report dizziness, fainting, slow heart rate, or difficulty breathing.

• Rise slowly to prevent falls (due to hypotension).

• Report abdominal cramping, diarrhea, or excessive salivation.

• Avoid in patients with asthma → risk of bronchospasm.

• Teach patient the goal: to initiate urination; monitor output closely.

Bethanechol Special Considerations 

• Contraindications:

  • Asthma or COPD (can cause bronchoconstriction)

  • Peptic ulcer disease (↑ gastric acid secretion)

  • Hypotension or bradycardia (can worsen)

  • Urinary or GI obstruction (may cause rupture or perforation)

Atropine

• A cholinergic antagonist used to treat bradycardia and reduce salivation during surgery. It works by blocking muscarinic receptors, leading to increased heart rate and decreased glandular secretions

Atropine Special Considerations 

• Contraindications:

  • Glaucoma (may increase intraocular pressure)

  • Myasthenia gravis (can exacerbate symptoms)

  • Severe tachycardia

  • Prostatic hypertrophy (may cause urinary retention)

• Use caution in elderly patients due to increased sensitivity to anticholinergic effects.

Atropine Patient teaching

• Patients should be advised to report any side effects such as blurred vision, dry mouth, or difficulty urinating.

• Drink fluids and increase fiber to help prevent constipation.

• Rise slowly from sitting to avoid dizziness from tachycardia or decreased sweating/heat intolerance.

Alpha 1 receptor

is a type of adrenergic receptor that primarily mediates vasoconstriction and increase in blood pressure when activated. It is commonly found in smooth muscles, blood vessels, bladder

Alpha 2 receptors 

are adrenergic receptors that inhibit neurotransmitter release and decrease sympathetic outflow. They are primarily located in post-ganglion sympathetic nerve endings

Beta 1 receptors

are a type of adrenergic receptor primarily found in the heart and kidneys, responsible for increasing heart rate and contractility when activated. They play a crucial role in managing cardiovascular functions.

• SE: increased HR, BP, renin and angiotensin

Beta 2 receptors

are adrenergic receptors that primarily mediate bronchodilation and vasodilation when activated. They are found in the lungs, liver, and GI

• can increase blood sugar as well

Alpha Blockers

• are medications that inhibit the action of alpha-adrenergic receptors, leading to vasodilation and a decrease in blood pressure. They are often used to treat hypertension and conditions like benign prostatic hyperplasia (improve urine flow) .

• SE: may include dizziness, orthostatic hypotension, and reflex tachycardia.

• hint: end in -sin

Beta Blockers

are a class of medications that block the effects of epinephrine on beta-adrenergic receptors, primarily used to manage cardiovascular conditions by reducing heart rate and blood pressure also for anxiety, migraines, glaucoma 

• SE: bradycardia, BP low, bronchospasm, blood sugar masking

• hint: end in LOL (think beta fish laughing)

Phenylephrine

• adrenergic agonist used for decongestion and vasopressor

• MOA: It works by stimulating alpha-1 adrenergic receptors, leading to vasoconstriction and increased blood pressure, as well as reducing nasal mucosa swelling.

• SE: may include hypertension, reflex bradycardia, and nasal dryness.

Special Considerations of Phenylephrine

• hypertensions or severe cardiovascular disease

• narrow angle glaucoma due to increased ocular pressure

• hyperthyroidism

• MAO inhibitors (risk hypertensive crisis)

Patient teaching for phenylephrine

• Take exactly as prescribed; do not exceed dose.

• Nasal spray:

  • Use short-term (≤3–5 days) to prevent rebound congestion.

  • Clear nasal passages before spraying.

• Report chest pain, palpitations, severe headache, or dizziness (possible hypertension).

• Avoid other stimulants (like caffeine) that may ↑ side effects.

• If you have hypertension, diabetes, or thyroid disease → consult provider before use.

Scopolamine

• anticholinergic/antiemetic drug used for motion sickness and nausea.

• MOA: Blocks acetylcholine (ACh) at muscarinic receptors in the CNS and vestibular system.This inhibits transmission of nerve signals from the vestibular apparatus (inner ear) to the vomiting center in the brain.

• SE:

  • Dry mouth, blurred vision, constipation, urinary retention

  • Drowsiness, confusion (especially in older adults)

Scopolamine Patient Teaching

• Avoid driving or hazardous activities until you know how it affects you (drowsiness, blurred vision possible).

• Report urinary retention, severe eye pain (possible acute glaucoma), or confusion.

• Increase fluids, chew sugarless gum, or use hard candy for dry mouth.

• Avoid alcohol or other CNS depressants → additive sedation.

Scopolamine Special Considerations

• Contraindications / Cautions:

  • Glaucoma (especially narrow-angle) → ↑ intraocular pressure

  • Urinary retention, BPH → worsens symptoms

  • Elderly → risk of confusion, hallucinations, sedation

Terazosin

• alpha 1 adrenergic blocker used to treat hypertension and BPH.

• MOA: Blocks alpha-1 adrenergic receptors, leading to vasodilation and decreased blood pressure, while relaxing smooth muscle in the prostate and bladder neck.

• SE: Dizziness, headache, orthostatic hypotension, nasal congestion

Terazosin Special Considerations

• First-dose phenomenon: Marked orthostatic hypotension and syncope may occur after the first dose (or dose increase).

• Monitor:

  • Blood pressure, especially after first dose

  • Dizziness, fainting, tachycardia

• Use cautiously with other antihypertensives (risk of additive hypotension).

Terazosin Patient teaching

• Take first dose at bedtime to minimize risk of fainting.

• Rise slowly from sitting/lying positions (orthostatic precautions).

• Report dizziness, palpitations, or fainting episodes.

• Continue taking medication even if you feel well (used long-term for BP and BPH control).

• Avoid alcohol and hot showers, which may worsen hypotension

Amphetamines

• are stimulant medications that increase the levels of DA and NE in the brain, resulting in increased alertness, attention, and energy

  • work on cerebral cortex 

  • work on ADHD and Narcolepsy 

  • addictive substance 

Amphetamines effects

1. increased alertness

2. euphoria

3. anorexia

4. tachycardia and palpitations

5. hallucinations

Anorexiants

• stimulate hypothalamus and limbic to promote feeling of fullness

• treatment in appetite suppressant

• sympathomimetic/parasympahtolytic

• contraindications for hypertension, hyperthyroidism, glaucoma and children under 12 (monitor BP, HR, sleep, and maintain nutrition intake)

Analeptics

• work in cerebral cortex, brain stem, and spinal cord

• used to reverse respiratory depression and migraines

• promotes cAMP accumulation leading to excitability

Methylphenidate

• stimulant that is amphetamine like used for ADHD

• MOA: blocks the reuptake of dopamine and norepinephrine, increasing their availability in the synaptic cleft, thereby enhancing attention and focus.

• SE: nsomnia, decreased appetite, anxiety, and increased heart rate

Methylphenidate special considerations

• Monitor growth, weight, and cardiovascular health during treatment. - Risk of dependency with long-term use.

• Assess for history of substance abuse, avoid use in patients with severe anxiety or agitation.

Methylphenidate Patient teaching

• Take in the morning to avoid insomnia.

• If a second dose is prescribed, take it in the early afternoon.

• Take 30–45 minutes before meals (can suppress appetite).

• Monitor weight regularly; encourage nutritious snacks.

• Do not stop abruptly → may cause withdrawal symptoms.

• Avoid caffeine and other stimulants.

Benzodiazepines 

• a class of medications that enhance the effect of the neurotransmitter GABA, decreasing neuron excitability.

• They are used to promote sleep, relieve stress and anxiety, provide muscle relaxation, and have anticonvulsant properties

• may suppress stage 4 NREM sleep and delay REM sleep.

Benzodiazepines Patient teaching 

• Take medication exactly as prescribed to prevent dependence and withdrawal symptoms. - Avoid alcohol and other CNS depressants. - Do not abruptly stop taking the medication. - Be aware of potential side effects such as drowsiness or confusion.

Antidote for benzodiazepines

Flumazenil, a GABA antagonist, used to reverse benzodiazepine overdose.

Hints for Benzo Drugs

• drugs with z in the middle of the name or ends in -lam or pam are benzos

• drugs with z toward the from are non-benzos

Diazepam

• a benzodiazepine used for anxiety, muscle spasms, and seizures.

• MOA: It enhances the effect of the neurotransmitter GABA at the GABA-A receptor, leading to sedation and muscle relaxation.

• SE: Common side effects include drowsiness, fatigue, and dizziness.

Diazepam Special Considerations 

• Use caution:

  • In elderly (risk of falls, delirium)

  • In patients with respiratory disorders (COPD, sleep apnea)

  • Avoid abrupt discontinuation → risk of withdrawal seizures

  • can cause respiratory depression 

Barbituates

• prolongs GABA and glycine : depressing neuronal activity

• blocks Na at high doses leading to electrolyte imbalances and fluid retention (COPD pts at risk)

• long half life

Barbiturate Hints

• drugs that end in -barbital are barbiturates

• effects include sedation, anticonvulsant, and anesthetic properties

• higher overdose risk compared to benzodiazepines (no antidote)

Melatonin Agonist 

• regulates circadian rhythm by mimicking the action of melatonin, helping to promote sleep.

• does not decrease REM and has a short half life

• ex: ramelteon and tasimelton

Sedative Considerations

• start low and go slow due to liver and kidney functioning slowing down making the drugs stay in their system longer

• avoid benzos w long half life like triazolmam