Medications 💊

1. Acetaminophen (Tylenol)

Mechanism

• Weak central (CNS) COX inhibitor

• Increases pain threshold

• Antipyretic via hypothalamus

• NOT anti-inflammatory

Targets

• CNS (brain)

• Liver (metabolism)

Major Considerations

• Hepatotoxic at > 4 g/day (2 g/day if alcoholic or liver disease)

• Monitor LFTs

• Antidote: N-Acetylcysteine (NAC)

• Safe in pregnancy

• Does NOT irritate stomach or cause bleeding

2. Aspirin (ASA)

Mechanism

• Irreversible inhibition of COX-1 and COX-2

• Blocks thromboxane A2 → prevents platelet aggregation

Targets

• Platelets

• GI tract

• Kidneys

• CNS (fever)

Major Considerations

• Bleeding risk (irreversible platelet inhibition for 7 days)

• Avoid in children → Reye syndrome

• Avoid in ulcers, GI bleed

• Watch for salicylate toxicity (tinnitus, metabolic acidosis)

3. Ibuprofen (NSAIDs)

Mechanism

• Reversible COX-1/COX-2 inhibition

• Anti-inflammatory, analgesic, antipyretic

Targets

• Peripheral tissues (inflammation)

• Kidneys

• GI tract

Major Considerations

• Nephrotoxicity

• GI irritation/ulcers

• ↑ BP and fluid retention

• Avoid with kidney injury

• Avoid in pregnancy (3rd trimester: closes fetal ductus arteriosus)

4. Tamsulosin (Flomax)

Mechanism

• α1A blocker in prostate & bladder neck → relaxes smooth muscle → improves urine flow

Targets

• Prostate

• Bladder neck

Major Considerations

• Orthostatic hypotension → fall risk

• First-dose syncope

• Retrograde ejaculation

• Give 30 min after same meal daily

• Caution with PDE5 inhibitors (sildenafil)

5. Ondansetron (Zofran)

Mechanism

• 5-HT3 serotonin receptor antagonist

• Blocks nausea/vomiting signals in brain and GI

Targets

• Chemoreceptor trigger zone (CTZ)

• Vagus nerve in GI tract

Major Considerations

• QT prolongation

• Risk of serotonin syndrome with SSRIs

• Give IV slowly (risk of arrhythmias)

• Headache & constipation

6. Montelukast (Singulair)

Mechanism

• Leukotriene receptor blocker

• Reduces inflammation and bronchoconstriction

• Maintenance asthma med (not for acute attack)

Targets

• Bronchi

• Immune cells (eosinophils, mast cells)

Major Considerations

• Black box: neuropsychiatric effects
  (anxiety, nightmares, depression)

• Take at night

• Not for acute bronchospasm

7. Oxycodone (Opioid Analgesic)

Mechanism

• Mu-opioid receptor agonist

• Blocks pain transmission in CNS

Targets

• Brain

• Spinal cord

• GI tract (slows motility)

Major Considerations

• Respiratory depression

• Constipation (treat with stimulant laxative)

• Sedation → fall risk

• Risk of dependence

• Avoid mixing with alcohol, benzos

• Antidote: Naloxone

8. Scopolamine

Mechanism

• Muscarinic antagonist

• Blocks acetylcholine in the vestibular system → stops motion sickness

Targets

• CNS vomiting center

• Parasympathetic nervous system

Major Considerations

• Patch lasts 72 hours

• Causes dry mouth, blurry vision, urinary retention

• Avoid in glaucoma (increases IOP)

• Remove old patches before applying new ones

9. Atropine

Mechanism

• Muscarinic receptor blocker

• ↑ HR by blocking vagus nerve

• Dries secretions

• Used in organophosphate poisoning

Targets

• Heart (SA node)

• Eyes

• Salivary and sweat glands

Major Considerations

• Tachycardia

• Urinary retention

• “Hot as a hare, dry as a bone, blind as a bat”

• Avoid in glaucoma (raises intraocular pressure)

10. Glaucoma Medications

A. Timolol (beta-blocker)

• ↓ aqueous humor production

• Target: ciliary body

• Watch for bradycardia, bronchospasm

B. Latanoprost

• ↑ aqueous humor outflow

• Target: uveoscleral pathway

• Side effect: iris color darkening, eyelash growth

C. Acetazolamide

• Carbonic anhydrase inhibitor → ↓ aqueous humor

• Watch for metabolic acidosis

D. Pilocarpine

• Muscarinic agonist → ↑ drainage

• Can cause miosis, headache

11. Gabapentin

Mechanism

• Blocks voltage-gated calcium channels

• Reduces excitatory neurotransmitter release

• Used for neuropathic pain & seizures

Targets

• CNS

• Dorsal horn neurons

Major Considerations

• Sedation

• Dizziness

• Ataxia

• Adjust dose in kidney disease

• NOT metabolized by liver

12. Carbidopa (in Carbidopa/Levodopa)

Mechanism

• Carbidopa inhibits peripheral dopa decarboxylase

• Allows more levodopa to reach the brain to become dopamine

• Reduces nausea from levodopa

Targets

• Peripheral tissues (GI tract, liver)

• Allows levodopa to act in brain (basal ganglia)

Major Considerations

• Take on empty stomach

• Avoid high-protein meals (↓ absorption)

• Dyskinesias over time

• Orthostatic hypotension

• Hallucinations (dopamine effect)

Summary Table (Fast Reference)

Drug	Target	Mechanism	Key Considerations
Tylenol	CNS	COX inhibition	Liver toxicity
Aspirin	Platelets	Irreversible COX block	Bleeding, ulcers
Ibuprofen	Peripheral tissues	COX block	Kidney injury
Flomax	Prostate	α1A block	Hypotension
Zofran	CTZ/GI	5-HT3 block	QT prolongation
Montelukast	Bronchi	Leukotriene block	Neuropsych effects
Oxycodone	CNS	Mu agonist	Respiratory depression
Scopolamine	CNS	Anticholinergic	Dry mouth, glaucoma
Atropine	Heart	Anticholinergic	Tachycardia, retention
Timolol	Eye	↓ Aqueous humor	Bradycardia
Gabapentin	CNS	Ca²⁺ channel block	Sedation
Carbidopa	Peripheral	DDC inhibitor	Nausea, dyskinesia