Top 50 Most Prescribed Medications

Why This Matters

As a pharmacology nurse, you're not just memorizing drug names—you're building a mental framework for understanding how medications work across body systems. The top prescribed medications represent the most common conditions you'll encounter: cardiovascular disease, metabolic disorders, mental health conditions, and chronic pain. Exam questions will test your ability to recognize drug classes, anticipate side effects, identify contraindications, and understand why one medication might be chosen over another for a specific patient.

These 50 medications demonstrate core pharmacological principles: receptor blocking, enzyme inhibition, hormone replacement, and neurotransmitter modulation. You'll see patterns emerge—ACE inhibitors and ARBs both target the renin-angiotensin system but through different mechanisms; SSRIs share a class but have different half-lives and interaction profiles. Don't just memorize individual drugs—know what mechanism each one illustrates and how drugs within the same class compare.

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Cardiovascular Agents: Blood Pressure & Heart Function

The cardiovascular medications you'll encounter most frequently work through distinct mechanisms: reducing cardiac workload, relaxing blood vessels, or blocking hormonal pathways that raise blood pressure. Understanding these mechanisms helps you anticipate side effects and recognize dangerous drug interactions.

Lisinopril

• ACE inhibitor that blocks conversion of angiotensin I to angiotensin II, reducing vasoconstriction and aldosterone secretion
• Dry cough is the hallmark side effect—caused by bradykinin accumulation; switch to ARB if intolerable
• Hyperkalemia risk requires monitoring potassium levels, especially when combined with potassium-sparing diuretics or in renal impairment

Losartan

• Angiotensin II receptor blocker (ARB) that blocks AT1 receptors directly—achieves similar endpoint as ACE inhibitors without affecting bradykinin
• No dry cough—making it the preferred alternative for patients who can't tolerate ACE inhibitors
• Renal protective effects in diabetic nephropathy make it first-line for hypertensive diabetics with proteinuria

Amlodipine

• Calcium channel blocker (dihydropyridine class) that relaxes vascular smooth muscle by blocking L-type calcium channels
• Peripheral edema is the most common side effect—caused by preferential arteriolar dilation, not fluid retention
• Long half-life (30-50 hours) allows once-daily dosing and provides stable blood pressure control

Metoprolol

• Beta-1 selective blocker that reduces heart rate, contractility, and myocardial oxygen demand
• Fatigue and bradycardia are expected effects—hold if heart rate drops below 60 bpm
• Do not stop abruptly—taper to avoid rebound tachycardia and hypertensive crisis

Hydrochlorothiazide

• Thiazide diuretic that inhibits sodium-chloride cotransporter in the distal convoluted tubule
• Hypokalemia, hyponatremia, and hyperuricemia are key electrolyte disturbances to monitor
• First-line for uncomplicated hypertension—often combined with ACE inhibitors or ARBs for synergistic effect

Furosemide

• Loop diuretic that inhibits sodium-potassium-chloride cotransporter in the ascending loop of Henle—most potent diuretic class
• Rapid fluid removal makes it essential for acute pulmonary edema and heart failure exacerbations
• Ototoxicity risk increases with high doses or concurrent aminoglycoside use

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Lipid-Lowering Agents: Statins & Cardiovascular Prevention

Statins remain the cornerstone of cardiovascular disease prevention. They work by inhibiting HMG-CoA reductase, the rate-limiting enzyme in cholesterol synthesis, which triggers upregulation of LDL receptors and increased clearance of LDL from the blood.

Atorvastatin

• High-intensity statin that can reduce LDL cholesterol by 50% or more at maximum doses
• Myopathy and rhabdomyolysis are serious risks—instruct patients to report unexplained muscle pain immediately
• Hepatic metabolism via CYP3A4 creates interaction potential with grapefruit juice, macrolides, and azole antifungals

Simvastatin

• Moderate-intensity statin with significant drug interaction profile due to CYP3A4 metabolism
• 80 mg dose restricted by FDA due to increased myopathy risk—most patients maintained at 40 mg or less
• Evening dosing recommended because cholesterol synthesis peaks at night

Aspirin

• Antiplatelet agent that irreversibly inhibits cyclooxygenase-1 (COX-1), preventing thromboxane A2 synthesis
• Low-dose (81 mg) for cardiovascular prevention—higher doses provide anti-inflammatory effects but increase bleeding risk
• GI bleeding risk is the primary concern—assess for concurrent NSAID use or anticoagulant therapy

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Metabolic & Endocrine Agents: Diabetes & Thyroid

Metabolic medications require precise dosing and careful monitoring. These drugs replace deficient hormones or modify glucose metabolism, and therapeutic windows can be narrow.

Metformin

• Biguanide antidiabetic that decreases hepatic glucose production and improves peripheral insulin sensitivity—does not cause hypoglycemia when used alone
• GI side effects (nausea, diarrhea) are common initially—start low and titrate slowly; extended-release formulation improves tolerability
• Hold before contrast procedures due to lactic acidosis risk in patients with renal impairment

Insulin Glargine

• Long-acting basal insulin with peakless 24-hour duration—mimics physiologic basal insulin secretion
• Cannot be mixed with other insulins due to acidic pH that would alter absorption kinetics
• Hypoglycemia risk requires patient education on signs, symptoms, and treatment with fast-acting glucose

Levothyroxine

• Synthetic T4 (thyroxine) that replaces deficient thyroid hormone in hypothyroidism
• Take on empty stomach 30-60 minutes before breakfast—calcium, iron, and antacids significantly reduce absorption
• Narrow therapeutic index requires regular TSH monitoring; symptoms of over-replacement mimic hyperthyroidism (tachycardia, weight loss, anxiety)

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Gastrointestinal Agents: Acid Suppression

Proton pump inhibitors dominate acid-related disorder treatment. They irreversibly inhibit the hydrogen-potassium ATPase pump in gastric parietal cells, providing more complete acid suppression than H2 blockers.

Omeprazole

• Proton pump inhibitor (PPI) that reduces gastric acid secretion by 90% or more when taken consistently
• Long-term risks include vitamin B12 deficiency, hypomagnesemia, Clostridioides difficile infection, and bone fractures
• CYP2C19 inhibitor that can reduce clopidogrel effectiveness—consider pantoprazole as alternative in cardiac patients

Pantoprazole

• PPI with fewer drug interactions than omeprazole—preferred in patients on clopidogrel or multiple CYP-metabolized drugs
• IV formulation available for patients who cannot take oral medications or have active GI bleeding
• Same long-term risks as other PPIs—use lowest effective dose for shortest duration

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Central Nervous System Agents: Mood & Anxiety

Antidepressants and anxiolytics work primarily by modulating neurotransmitter availability. SSRIs increase serotonin in the synaptic cleft by blocking reuptake, while other agents have multimodal mechanisms.

Sertraline

• SSRI with favorable side effect profile and broad FDA indications including depression, PTSD, OCD, and panic disorder
• Fewer drug interactions than other SSRIs—relatively safe in patients on multiple medications
• Sexual dysfunction and GI upset are common; serotonin syndrome risk with MAOIs, tramadol, or other serotonergic agents

Escitalopram

• S-enantiomer of citalopram—more potent and selective than parent compound
• QT prolongation risk is lower than citalopram but still requires caution with other QT-prolonging drugs
• Generally well-tolerated with predictable dosing—often first-line for generalized anxiety disorder

Fluoxetine

• SSRI with longest half-life (4-6 days for active metabolite)—self-tapering reduces discontinuation syndrome risk
• Strong CYP2D6 inhibitor creates significant drug interaction potential with codeine, tamoxifen, and many antipsychotics
• Activating profile may worsen anxiety initially—better for patients with fatigue and low motivation

Trazodone

• Serotonin antagonist and reuptake inhibitor (SARI) with strong sedating properties at low doses
• Off-label insomnia use is more common than antidepressant use—typically 25-100 mg at bedtime
• Priapism is a rare but serious side effect requiring immediate medical attention

Gabapentin

• GABA analog that paradoxically does not bind GABA receptors—works by binding alpha-2-delta subunit of voltage-gated calcium channels
• Neuropathic pain and seizure indications—also used off-label for anxiety and alcohol withdrawal
• Renal elimination requires dose adjustment in kidney disease; sedation and peripheral edema are common

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Pain Management: Opioids, NSAIDs & Adjuvants

Pain medications range from mild anti-inflammatories to potent opioids. Understanding the analgesic ladder and multimodal pain management is essential for safe prescribing and administration.

Hydrocodone/Acetaminophen

• Schedule II opioid combination providing moderate-to-severe pain relief through mu-opioid receptor agonism
• Acetaminophen hepatotoxicity limits total daily dose—monitor for concurrent acetaminophen use in OTC products
• Respiratory depression, constipation, and dependence require careful patient selection and monitoring

Ibuprofen

• NSAID that inhibits both COX-1 and COX-2 enzymes, reducing prostaglandin synthesis
• GI bleeding, renal impairment, and cardiovascular risk increase with prolonged use or high doses
• Avoid in third trimester of pregnancy due to premature ductus arteriosus closure

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Respiratory Agents: Bronchodilators & Anti-Inflammatories

Respiratory medications target airway smooth muscle or inflammatory pathways. Quick-relief bronchodilators provide immediate symptom control, while controller medications prevent exacerbations.

Albuterol

• Short-acting beta-2 agonist (SABA) that relaxes bronchial smooth muscle within minutes
• Rescue inhaler for acute bronchospasm—increased use indicates poor asthma control and need for controller therapy
• Tremor and tachycardia result from beta-receptor stimulation; hypokalemia possible with frequent use

Montelukast

• Leukotriene receptor antagonist that blocks inflammatory mediators in asthma and allergic rhinitis
• FDA boxed warning for neuropsychiatric effects including mood changes, suicidal ideation—monitor and counsel patients
• Once-daily oral dosing improves adherence compared to inhaled controllers

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Anti-Infectives: Antibiotics

Antibiotic stewardship requires understanding mechanisms, spectrums, and resistance patterns. Selecting the right antibiotic depends on likely pathogens, site of infection, and patient factors.

Amoxicillin

• Aminopenicillin with broad gram-positive and some gram-negative coverage—inhibits bacterial cell wall synthesis by binding penicillin-binding proteins
• First-line for strep pharyngitis, otitis media, and community-acquired pneumonia in appropriate patients
• Cross-reactivity with cephalosporins is lower than historically believed—approximately 1% in penicillin-allergic patients

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Quick Reference Table

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Self-Check Questions

1. A patient on lisinopril develops a persistent dry cough. What medication class would you expect the provider to switch to, and why does this substitution resolve the cough?

2. Compare metformin and insulin glargine: Which can cause hypoglycemia when used as monotherapy, and what makes metformin the preferred first-line agent for type 2 diabetes?

3. A cardiac patient needs a PPI for GERD but is also taking clopidogrel. Which PPI would be preferred and why?

4. What distinguishes furosemide from hydrochlorothiazide in terms of potency and clinical indications? When would you use each?

5. A patient is prescribed both albuterol and montelukast for asthma. Explain the role of each medication and what it would indicate if the patient is using albuterol multiple times daily.