Sympathomimetic Drugs

Below is your **COMPLETE, ADVANCED, STYLISH MEDICAL NOTE** on **SYMPATHOMIMETIC DRUGS** — formatted beautifully, NEET-PG ready, ultra-structured, and exhaustive. --- # ⭐ **Sympathomimetic Drugs — Complete Stylish Note (Ultra-Advanced)** --- # 🎯 **1. Definition** **Sympathomimetics** are drugs that **mimic the actions of endogenous catecholamines** (epinephrine, norepinephrine, dopamine) by stimulating **α, β, or dopamine receptors** of the **sympathetic nervous system**. --- # 🔬 **2. Pathophysiology / Mechanism of Action** ### **A. Direct-acting** Bind directly to adrenergic receptors: **α₁ agonists:** vasoconstriction **α₂ agonists:** ↓ sympathetic outflow → ↓ BP **β₁ agonists:** ↑ HR, ↑ contractility **β₂ agonists:** bronchodilation, tocolysis **Dopamine agonists:** renal vasodilation ### **B. Indirect-acting** ↑ endogenous catecholamines – Promote NE release → *amphetamine* – Inhibit reuptake → *cocaine, TCA* – Inhibit metabolism → *MAO inhibitors & COMT inhibitors* ### **C. Mixed-acting** – *Ephedrine*: directly stimulates α & β; releases NE – *Pseudoephedrine*: nasal decongestant --- # 🧪 **3. Classification of Sympathomimetic Drugs** --- ## 🌟 **A. Direct-Acting Agents** ### **1. α₁ Selective Agonists** | Drug | Use | | ----------------- | ----------------------------- | | **Phenylephrine** | Nasal decongestant, mydriasis | | **Midodrine** | Orthostatic hypotension | | **Methoxamine** | Vasopressor | ### **2. α₂ Selective Agonists** | Drug | Use | | ------------------- | ---------------------------- | | **Clonidine** | HTN, ADHD, opioid withdrawal | | **Methyldopa** | Pregnancy HTN | | **Dexmedetomidine** | ICU sedation | | **Tizanidine** | Muscle spasticity | --- ### **3. β₁ Selective Agonists** | Drug | Use | | -------------- | -------------------------------- | | **Dobutamine** | Acute heart failure, stress test | | **Xamoterol** | Partial β₁ agonist | --- ### **4. β₂ Selective Agonists** **Short-acting (SABA):** – **Salbutamol**, **Terbutaline** **Long-acting (LABA):** – **Salmeterol**, **Formoterol** **Ultra-long:** – **Indacaterol**, **Olodaterol** **Uses:** Bronchodilation, tocolysis --- ### **5. Mixed α + β Agonists** | Drug | Receptor | Use | | ------------------ | ----------- | --------------------------- | | **Epinephrine** | α₁ α₂ β₁ β₂ | Anaphylaxis, cardiac arrest | | **Norepinephrine** | α₁ α₂ β₁ | Septic shock | | **Isoproterenol** | β₁ β₂ | Torsades, AV block | --- ### **6. Dopamine Receptor Agonists** | Dose | Effect | | --------- | ----------------------- | | Low dose | Renal vasodilation (D₁) | | Moderate | ↑ cardiac output (β₁) | | High dose | Vasoconstriction (α₁) | --- # 🚨 **4. Pharmacokinetics (PK) Essentials** * Catecholamines **short half-life**, metabolized by **MAO & COMT** * Non-catecholamines (ephedrine, amphetamine) **longer acting**, CNS penetration * Most require IV for acute indications * Renal & hepatic clearance varies widely --- # 🎭 **5. Clinical Effects (Organ-wise)** ## **Heart** * β₁ → ↑ HR, ↑ contractility * α₁ → ↑ afterload (vasoconstriction) ## **Lungs** * β₂ → bronchodilation, ↓ mast cell degranulation ## **Eye** * α₁ → mydriasis * β₂ → ↓ aqueous humor ## **Uterus** * β₂ → tocolysis ## **Metabolic** * β₂ → ↑ glycogenolysis, ↑ lipolysis * β₁ → ↑ renin --- # 🧠 **6. Indications (With First-Line Drugs)** ### ✔ **Shock** * **Septic shock:** Norepinephrine * **Cardiogenic:** Dobutamine * **Anaphylaxis:** Epinephrine * **Neurogenic shock:** Phenylephrine ### ✔ **Asthma** * SABA: Salbutamol * Status asthmaticus: Nebulized salbutamol ± ipratropium ### ✔ **Preterm Labor** * Terbutaline ### ✔ **Nasal Decongestion** * Phenylephrine * Xylometazoline * Oxymetazoline ### ✔ **Glaucoma** * Brimonidine (α₂) ### ✔ **Hypertension** * Clonidine * Methyldopa (pregnancy) --- # ⚠️ **7. Adverse Effects (Drug-wise)** ## **α₁ Agonists** * Hypertension * Headache * Ischemia * Urinary retention ## **α₂ Agonists** * Sedation * Rebound HTN (clonidine withdrawal) ## **β₁ Agonists** * Tachycardia * Arrhythmias * Palpitations ## **β₂ Agonists** * Tremor * Hypokalemia * Hyperglycemia * Tachycardia ## **Dopamine Agonists** * Arrhythmias * Gangrene (high-dose α₁ vasoconstriction) --- # ⛔ **8. Contraindications** * Hyperthyroidism (↑ sensitivity) * Severe CAD * Pheochromocytoma * MAOI use (risk of hypertensive crisis) --- # 🔥 **9. Drug–Drug Interactions** * **MAOI + sympathomimetics → hypertensive crisis** * **TCAs → exaggerated pressor response** * **β-blockers block β agonists → unopposed α (dangerous)** * **Cocaine + epinephrine → severe HTN, arrhythmia** --- # 📊 **10. Monitoring** * HR, BP, ECG * Serum potassium for β₂ agonists * Blood glucose * Urine output (shock) * Peripheral perfusion (vasopressors) --- # 🎓 **11. High-Yield NEETPG Points** 🔥 Epinephrine is the **drug of choice for anaphylaxis** 🔥 Norepinephrine is **first-line for septic shock** 🔥 Clonidine withdrawal → **rebound hypertension** 🔥 Salbutamol → **hypokalemia** 🔥 α₂ agonists → **↓ sympathetic outflow** 🔥 Isoproterenol → widest pulse pressure 🔥 Dopamine dose-dependent receptor effect = exam favorite --- # 📝 **12. Quick Comparison Table** | Drug | Receptors | Major Use | | -------------- | ----------- | ------------------------- | | Epinephrine | α₁ α₂ β₁ β₂ | Anaphylaxis | | Norepinephrine | α₁ α₂ β₁ | Septic shock | | Dobutamine | β₁ | Cardiogenic shock | | Salbutamol | β₂ | Asthma | | Phenylephrine | α₁ | Hypotension, decongestion | | Clonidine | α₂ | HTN, withdrawal | | Dopamine | D₁ β₁ α₁ | Shock (dose-dependent) | --- # 🌈 **13. Beautiful Last-Minute Revision Mnemonics** ### **Sympathomimetic Receptors: “A1 = Arteries, B1 = Beats, B2 = Bronchi + Baby (uterus)”** ### **α₂ effects: “2 things ↓ — BP ↓ & Sympathetic ↓”** ### **Dopamine: “D-B-A” (Dose-based receptors)** * **D** — Low dose * **B** — β₁ * **A** — α₁ high dose --- # ✅ Done! If you want: 🔥 **Case scenarios** 🔥 **HTML + CSS + JS MCQs (20–30)** 🔥 **Tags for your VidShare/MedicalMCQ sites** 🔥 **Image generation** Just tell me **“give MCQs + scenarios + image”** and I’ll deliver. Nice, let’s turn this into a **full clinical case bank**. Below are **30 detailed case scenarios** on **sympathomimetic drugs** with: * Scenario + diagnosis * Exact **drug & dose (adult)** * **Stepwise management algorithm** * **Important adverse effects & monitoring** > ⚠️ *Educational only – real patients must be treated as per local protocols & specialist guidance.* --- ## 🩺 Case 1 – Anaphylactic Shock After Bee Sting (Epinephrine IM) **Scenario:** 24-year-old man, sudden breathlessness, wheeze, urticaria, BP 70/40, HR 130, after bee sting. **Key Diagnosis:** Anaphylactic shock. **Drug & Dose (Adult):** * **Epinephrine 0.3–0.5 mg IM** (0.3–0.5 mL of 1:1000) in anterolateral thigh. * Repeat every **5–15 min** as needed. **Management Algorithm:** 1. **Airway:** High-flow O₂, prepare for intubation if stridor/impending arrest. 2. **Epinephrine IM** immediately (do NOT delay for IV access). 3. **IV access + fluids:** Rapid 1–2 L isotonic crystalloid bolus. 4. **Adjuncts:** * H1 blocker: Chlorpheniramine IV * H2 blocker: Ranitidine IV (optional) * Steroid: Hydrocortisone 200 mg IV 5. **Bronchospasm:** Add **nebulized salbutamol** if wheeze persists. 6. **Observe** at least **4–6 h** (longer for severe cases/biphasic reactions). **Adverse Effects & Monitoring (Epinephrine):** * Tachycardia, arrhythmias, hypertension, tremor, anxiety. * Monitor: ECG, BP, HR, O₂ saturation, urine output. --- ## 🩺 Case 2 – Septic Shock (Norepinephrine Infusion) **Scenario:** 65-year-old with pneumonia, hypotension (80/50) despite 30 mL/kg fluids, lactate ↑, cold peripheries. **Key Diagnosis:** Septic shock. **Drug & Dose:** * **Norepinephrine IV infusion**: start **0.05–0.1 mcg/kg/min**, titrate to maintain MAP ≥ 65 mmHg. **Management Algorithm:** 1. **Initial resuscitation:** * High-flow O₂ * 30 mL/kg crystalloid in first 3 hours 2. **Start norepinephrine via central line** (preferably) with infusion pump. 3. **Titrate dose** every 5–10 min to MAP ≥ 65. 4. Add **vasopressin** or **epinephrine** if refractory (not first-line detail, but concept). 5. Start **broad-spectrum antibiotics within 1 hour**, source control. 6. Monitor: lactate, urine output, organ function. **Adverse Effects & Monitoring (Norepinephrine):** * Peripheral ischemia, arrhythmias, hypertension. * Watch for **extravasation** (risk of tissue necrosis), continuous BP & ECG monitoring. --- ## 🩺 Case 3 – Cardiogenic Shock Post-MI (Dobutamine) **Scenario:** 58-year-old man post-anterior MI, BP 85/55, cool extremities, reduced urine output, pulmonary congestion. **Key Diagnosis:** Cardiogenic shock. **Drug & Dose:** * **Dobutamine IV infusion**: **2–20 mcg/kg/min**, titrate to effect. **Management Algorithm:** 1. O₂, monitor ECG, BP, urine output. 2. Treat underlying MI (antiplatelets, anticoagulation, reperfusion if possible). 3. Start **dobutamine** for low cardiac output with adequate BP. 4. Adjust rate to improve perfusion (urine output, mentation, BP). 5. Avoid excessive tachycardia; consider adding vasopressor if BP too low. **Adverse Effects & Monitoring:** * Tachycardia, arrhythmias, angina, hypotension (if vasodilation predominates). * Continuous ECG, BP, signs of ischemia. --- ## 🩺 Case 4 – Low Output + Renal Hypoperfusion (Dopamine) **Scenario:** 72-year-old in mixed septic–cardiogenic shock, oliguria (urine < 0.3 mL/kg/h), MAP borderline. **Key Diagnosis:** Shock with renal hypoperfusion. **Drug & Dose:** * **Dopamine IV infusion** * **2–5 mcg/kg/min** → dopaminergic (renal vasodilation) * **5–10 mcg/kg/min** → β₁ (↑CO) * **>10 mcg/kg/min** → α₁ (vasoconstriction) **Management Algorithm:** 1. Fluid resuscitation first. 2. Start dopamine at **2–5 mcg/kg/min**, titrate based on BP & urine output. 3. Avoid prolonged high doses (risk of ischemia). 4. Reassess repeatedly; if not effective, switch to norepinephrine/dobutamine per protocol. **Adverse Effects & Monitoring:** * Tachyarrhythmias, myocardial ischemia, peripheral ischemia, nausea. * Monitor ECG, BP, limbs, urine output. --- ## 🩺 Case 5 – Status Asthmaticus (High-Dose Salbutamol) **Scenario:** 20-year-old with asthma, severe dyspnea, RR 34, SpO₂ 88%, cannot complete sentences, use of accessory muscles. **Key Diagnosis:** Severe acute asthma exacerbation. **Drug & Dose:** * **Salbutamol nebulization 2.5–5 mg** every **20 min for first hour**, then as needed. **Management Algorithm:** 1. O₂ to keep SpO₂ ≥ 94%. 2. **Nebulized salbutamol** + **ipratropium**. 3. IV steroids: e.g., Methylprednisolone 40–80 mg IV. 4. If no response: consider IV MgSO₄, possible ICU/intubation. 5. Avoid sedatives. **Adverse Effects & Monitoring (Salbutamol):** * Tremor, tachycardia, palpitations, **hypokalemia**, hyperglycemia. * Monitor HR, BP, serum K⁺ if frequent dosing. --- ## 🩺 Case 6 – Preterm Labor (Terbutaline) **Scenario:** 28-year-old at 31 weeks gestation, regular contractions, cervix 2 cm, intact membranes. **Key Diagnosis:** Threatened preterm labor. **Drug & Dose:** * **Terbutaline 0.25 mg SC**, can repeat every **20–30 min** up to **3 doses**, then infusion if used per protocol. **Management Algorithm:** 1. Confirm preterm labor (exclude infection, abruption, fetal distress). 2. Give **terbutaline** SC (tocolysis) if no contraindications (e.g., severe preeclampsia). 3. Administer **antenatal corticosteroids** for lung maturity. 4. Monitor maternal HR, BP, glucose, fetal heart rate. 5. Avoid prolonged β₂ agonist use in high-risk cardiac patients. **Adverse Effects & Monitoring:** * Maternal tachycardia, tremor, hyperglycemia, **pulmonary edema**, hypotension. * Fetal tachycardia. * Strict fluid balance and vitals monitoring. --- ## 🩺 Case 7 – Chronic Asthma Control (LABA + ICS) **Scenario:** 35-year-old with daily asthma symptoms, uses SABA > 3×/week, nocturnal symptoms. **Key Diagnosis:** Moderate persistent asthma. **Drug & Dose (LABA part):** * **Salmeterol 50 mcg inhaled BID** (always with inhaled corticosteroid). **Management Algorithm:** 1. Confirm diagnosis (spirometry). 2. Step-up therapy: **ICS + LABA combo inhaler**. 3. Educate on inhaler technique, adherence, trigger avoidance. 4. Review after 4–6 weeks, adjust step up/down. **Adverse Effects (LABA):** * Tremor, palpitations, headache, rarely paradoxical bronchospasm. * Do **not** use LABA without ICS in asthma (↑ mortality risk). --- ## 🩺 Case 8 – Mild Intermittent Asthma (Rescue SABA) **Scenario:** 19-year-old with exercise-induced wheeze, rare symptoms. **Key Diagnosis:** Mild intermittent asthma. **Drug & Dose:** * **Salbutamol 100–200 mcg (1–2 puffs)** via MDI **as needed**, or before exercise. **Management Algorithm:** 1. Provide reliever SABA inhaler. 2. Educate: use spacer, pre-exercise prophylaxis. 3. Avoid overuse (>2 days/week → step up). **Adverse Effects & Monitoring:** * Tremor, tachycardia; monitor usage frequency (marker of poor control). --- ## 🩺 Case 9 – Nasal Congestion (Topical α₁ Agonist) **Scenario:** 30-year-old with acute viral rhinitis, severe nasal congestion. **Key Diagnosis:** Acute nasal congestion. **Drug & Dose:** * **Xylometazoline or Oxymetazoline 0.05%** – 1–2 sprays per nostril **every 8–12 h**, max **3–5 days**. **Management Algorithm:** 1. Short-term topical α agonist for symptomatic relief. 2. Saline irrigation, hydration, steam inhalation. 3. Emphasize duration limit to avoid rebound congestion. **Adverse Effects & Monitoring:** * Local irritation, dryness, **rebound congestion (rhinitis medicamentosa)** if >5–7 days. * Rare systemic hypertension, tachycardia (if absorbed). --- ## 🩺 Case 10 – Orthostatic Hypotension (Midodrine) **Scenario:** 65-year-old with diabetic autonomic neuropathy, dizziness on standing, BP drop > 20 mmHg systolic. **Key Diagnosis:** Neurogenic orthostatic hypotension. **Drug & Dose:** * **Midodrine 2.5–10 mg PO, 2–3 times/day** (avoid close to bedtime). **Management Algorithm:** 1. Non-pharmacologic: slow position change, compression stockings, salt & fluid optimization. 2. Start low-dose midodrine, titrate to symptom control. 3. Avoid dose within 4 hours of sleep (risk of supine HTN). **Adverse Effects & Monitoring:** * Supine hypertension, piloerection, pruritus, urinary retention. * Monitor supine vs standing BP, urinary symptoms. --- ## 🩺 Case 11 – ICU Sedation & Sympathetic Control (Dexmedetomidine) **Scenario:** Intubated ICU patient with agitation, tachycardia, high sympathetic tone. **Key Diagnosis:** Need for light sedation with sympathetic dampening. **Drug & Dose:** * **Dexmedetomidine IV infusion 0.2–0.7 mcg/kg/h**, usually **without bolus**. **Management Algorithm:** 1. Start continuous infusion, titrate to sedation scale target (e.g., RASS –1 to 0). 2. Reduce other sedatives/opioids as tolerated. 3. Avoid bolus in unstable patients (risk of brady/hypotension). **Adverse Effects & Monitoring:** * Bradycardia, hypotension, dry mouth. * Continuous BP & HR monitoring. --- ## 🩺 Case 12 – Hypertensive Urgency Managed with Clonidine **Scenario:** 45-year-old with BP 200/110, headache, but no acute organ damage. **Key Diagnosis:** Hypertensive urgency. **Drug & Dose:** * **Clonidine 0.1–0.2 mg PO** initially, then **0.1 mg hourly** up to total **0.6–0.7 mg** (as per protocol). **Management Algorithm:** 1. Rule out hypertensive emergency (neuro deficits, chest pain, AKI). 2. If urgency: use **oral clonidine** in monitored setting. 3. Gradual BP reduction over 24–48 h. 4. Start/adjust long-term antihypertensives. 5. Avoid abrupt cessation: taper dose. **Adverse Effects & Monitoring:** * Sedation, dry mouth, bradycardia, constipation. * **Rebound hypertension** with abrupt withdrawal. * Monitor BP, HR, mental status. --- ## 🩺 Case 13 – Pregnancy-Induced Hypertension (Methyldopa) **Scenario:** 28-year-old, 30 weeks pregnant, BP 150/98, no proteinuria. **Key Diagnosis:** Gestational hypertension. **Drug & Dose:** * **Methyldopa 250 mg PO 2–3 times/day**, titrate (max ~3 g/day). **Management Algorithm:** 1. Confirm diagnosis, assess for preeclampsia. 2. Start methyldopa, titrate based on BP response. 3. Regular follow-up BP, fetal growth monitoring. 4. Consider switching postpartum. **Adverse Effects & Monitoring:** * Sedation, depression, dry mouth, hepatic dysfunction, hemolytic anemia (rare). * Monitor LFTs, CBC if long-term. --- ## 🩺 Case 14 – Resistant HTN on Multiple Drugs (Clonidine Add-On) **Scenario:** 60-year-old with HTN on ACEI + CCB + diuretic, still BP 170/100. **Key Diagnosis:** Resistant hypertension. **Drug & Dose:** * **Clonidine 0.1 mg PO BID**, titrate. **Management Algorithm:** 1. Confirm adherence, rule out secondary causes. 2. Add centrally acting α₂ agonist (clonidine) as fourth-line. 3. Educate about not stopping abruptly. 4. Regular BP, HR monitoring. **Adverse Effects & Monitoring:** * Sedation, dry mouth, bradycardia, **rebound HTN**. * Monitor mood (risk of depression). --- ## 🩺 Case 15 – AV Block with Bradycardia (Isoproterenol) **Scenario:** 50-year-old with symptomatic second-degree AV block, HR 30, dizziness, hypotension, awaiting pacemaker. **Key Diagnosis:** Symptomatic bradycardia / AV block. **Drug & Dose:** * **Isoproterenol IV infusion 2–10 mcg/min**, titrate to HR and BP. **Management Algorithm:** 1. Atropine if appropriate; if ineffective and pacing not immediately available → **isoproterenol**. 2. Continuous ECG & BP monitoring. 3. Use as **bridge to pacemaker** implantation. **Adverse Effects & Monitoring:** * Tachyarrhythmias, angina, hypotension (due to β₂ vasodilation). * Avoid in ischemic heart disease if possible. --- ## 🩺 Case 16 – Torsades de Pointes with Bradycardia (Isoproterenol) **Scenario:** Patient with long QT syndrome, recurrent polymorphic VT (torsades), bradycardia. **Key Diagnosis:** Torsades requiring HR acceleration. **Drug & Dose:** * **Isoproterenol IV 2–10 mcg/min** to increase HR and shorten QT. **Management Algorithm:** 1. Correct hypokalemia, hypomagnesemia (MgSO₄ IV). 2. Discontinue QT-prolonging drugs. 3. If bradycardia-induced torsades: **isoproterenol** or temporary pacing. 4. Continuous ECG monitoring. **Adverse Effects & Monitoring:** * Same as Case 15. --- ## 🩺 Case 17 – Open-Angle Glaucoma (Brimonidine) **Scenario:** 55-year-old with open-angle glaucoma, requires add-on to prostaglandin analog. **Key Diagnosis:** Chronic glaucoma. **Drug & Dose:** * **Brimonidine 0.1–0.2% eye drops**, 1 drop **TID**. **Management Algorithm:** 1. Continue baseline prostaglandin analog. 2. Add brimonidine to reduce aqueous humor production and ↑ uveoscleral outflow. 3. Regular IOP checks, optic nerve monitoring. **Adverse Effects & Monitoring:** * Ocular allergy, conjunctival hyperemia, dry mouth, fatigue. * Avoid in infants (risk of apnea, CNS depression). --- ## 🩺 Case 18 – Acute Hypotension During Spinal Anesthesia (Phenylephrine) **Scenario:** Woman undergoing C-section under spinal, BP drops to 70/40, HR 90. **Key Diagnosis:** Spinal-induced hypotension. **Drug & Dose:** * **Phenylephrine 50–100 mcg IV bolus**, may repeat; or infusion 0.25–1 mcg/kg/min. **Management Algorithm:** 1. Left uterine displacement, O₂, check airway & breathing. 2. Rapid IV fluid bolus. 3. Give IV phenylephrine bolus; repeat if needed or start infusion. 4. Continuous BP, HR, fetal monitoring. **Adverse Effects & Monitoring:** * Reflex bradycardia, hypertension, decreased uterine blood flow (if excessive). * Monitor BP, HR closely. --- ## 🩺 Case 19 – Cardiac Stress Test (Dobutamine Stress Echo) **Scenario:** Patient cannot exercise on treadmill, needs ischemia evaluation. **Key Diagnosis:** Need for pharmacologic stress. **Drug & Dose:** * **Dobutamine IV**: incremental doses (e.g., 5 → 10 → 20 → 30–40 mcg/kg/min) in stages. **Management Algorithm:** 1. Baseline ECG, echo, vitals. 2. Start dobutamine; increase dose every 3 min while monitoring. 3. Stop if: target HR achieved, ischemia on ECG/echo, severe symptoms/arrhythmia. **Adverse Effects & Monitoring:** * Tachycardia, arrhythmias, angina. * Continuous ECG, BP, symptoms. --- ## 🩺 Case 20 – β₂ Agonist Overuse (Salbutamol Toxicity) **Scenario:** Asthmatic patient using salbutamol inhaler >15–20 puffs/day, palpitations, tremor, muscle cramps. **Key Diagnosis:** β₂ agonist overuse → toxicity. **Management Algorithm (No specific antidote, but supportive):** 1. Reduce SABA use, step up controller (ICS ± LABA). 2. Check **serum potassium** and correct hypokalemia. 3. Monitor HR, BP, ECG for arrhythmia. **Adverse Effects & Monitoring:** * Tremor, tachycardia, palpitations, hypokalemia, hyperglycemia. --- ## 🩺 Case 21 – Clonidine Withdrawal Rebound Hypertension **Scenario:** Patient on clonidine for HTN abruptly stops; BP 220/120, severe headache. **Key Diagnosis:** Rebound hypertensive crisis. **Management Algorithm:** 1. Restart clonidine or give short-acting antihypertensive (e.g., labetalol), as per protocol. 2. Avoid rapid BP drop; gradually control. 3. Educate patient on tapering. **Adverse Effects:** * Severe rebound HTN, headache, agitation, tachycardia. * Monitor BP & neuro status closely. --- ## 🩺 Case 22 – ADHD Child (Dexmethylphenidate vs Sympathomimetics Context) *(Not a classic peripheral sympathomimetic like epi/NE, but central stimulant with sympathomimetic actions.)* **Scenario:** 8-year-old with ADHD, poor school performance. **Drug (conceptual):** Central stimulant with indirect sympathomimetic activity. **Key Points (Exam Concept):** * Increases NE/DA in CNS. * AE: ↓ appetite, insomnia, tachycardia, ↑ BP. *(Detailing dose skipped here since it moves beyond classic adrenergic agonist list.)* --- ## 🩺 Case 23 – Decongestant Overuse (Rhinitis Medicamentosa) **Scenario:** Man using oxymetazoline drops for 4 weeks, now severe constant congestion. **Key Diagnosis:** Rhinitis medicamentosa. **Management Algorithm:** 1. Gradually withdraw topical decongestant. 2. Switch to **intranasal steroids + saline**. 3. Educate: future use ≤3–5 days. **Adverse Effects (Topical α agonists):** * Chronic mucosal edema, rebound congestion, rarely systemic HTN/Tachy. --- ## 🩺 Case 24 – Obstructive Sleep Apnea with Daytime BP Spikes (Sympathetic Overactivity) **Scenario:** OSA patient with early morning hypertension, tachycardia. **Key Concept:** Chronic **sympathetic overdrive**, not directly treated with sympathomimetic but relevant pathophysiology. **Management:** * Treat OSA (CPAP), weight loss, BP control. * Avoid unnecessary sympathomimetics at night. --- ## 🩺 Case 25 – Epinephrine in Cardiac Arrest (ACLS) **Scenario:** Adult in pulseless VT/VF. **Drug & Dose:** * **Epinephrine 1 mg IV** (1:10,000) every **3–5 min** during CPR. **Management Algorithm (ACLS core):** 1. High-quality CPR, defibrillation as indicated. 2. Epinephrine IV/IO q3–5 min. 3. Treat reversible causes (H’s & T’s). **Adverse Effects:** * Not a concern during arrest, but post-ROSC: hypertension, tachyarrhythmia. --- ## 🩺 Case 26 – Epinephrine for Severe Croup (Nebulized) **Scenario:** Child with severe stridor, barking cough, chest retractions. **Drug & Dose:** * **Nebulized racemic epinephrine** (exact dose per preparation; concept: α-induced mucosal vasoconstriction). **Algorithm:** 1. Keep child calm, O₂ if needed. 2. Nebulized epinephrine + systemic steroids. 3. Observe for rebound obstruction. **Adverse Effects:** * Tachycardia, hypertension, agitation; monitor HR & resp status. --- ## 🩺 Case 27 – Emergency Bronchodilation in Hyperkalemia (Salbutamol) **Scenario:** Patient with CKD, K⁺ 6.8, ECG changes (peaked T waves). **Drug & Dose:** * **Nebulized Salbutamol 10–20 mg** over ~10–20 min (high-dose, off-label concept). **Algorithm:** 1. IV calcium gluconate (membrane stabilization). 2. IV insulin + dextrose. 3. **High-dose salbutamol** to drive K⁺ into cells. 4. Consider dialysis. **Adverse Effects:** * Tachycardia, tremor, lactic acidosis; monitor ECG, K⁺. --- ## 🩺 Case 28 – Emergency Hypotension in Anesthesia (Epinephrine Mini-Dose) **Scenario:** Intra-operative sudden hypotension, suspected anaphylactoid reaction. **Drug & Dose:** * **Epinephrine 10–50 mcg IV bolus** (titrated) in monitored OR setting. **Algorithm:** 1. Stop suspected trigger, 100% O₂. 2. Give titrated IV epinephrine boluses. 3. Fluids, adjuncts (H1/H2 blocker, steroid). **Adverse Effects:** * Arrhythmias, severe hypertension if overdosed. --- ## 🩺 Case 29 – Off-Label Use of Phenylephrine for Priapism (Conceptual) **Scenario:** Ischemic priapism >4 h. **Drug & Dose:** * **Phenylephrine 100–500 mcg** diluted and injected intracavernosally by specialist. **Algorithm:** 1. Analgesia, aspiration of blood from corpora. 2. Intracavernosal phenylephrine at intervals. **Adverse Effects:** * Hypertension, reflex bradycardia, arrhythmias. * Monitor BP & HR continuously. --- ## 🩺 Case 30 – Toxic Sympathomimetic Syndrome (Amphetamine/Cocaine) **Scenario:** Young man with agitation, sweating, tachycardia, hypertension, dilated pupils after stimulant use. **Key Concept:** **Sympathomimetic toxidrome.** **Management Algorithm (No more sympathomimetics!):** 1. Sedate with **benzodiazepines** (NOT β-blocker alone in cocaine). 2. Control BP with vasodilators (e.g., nitroprusside) as per protocol. 3. Cool patient, correct metabolic derangements. **Adverse Effects (Drugs themselves):** * Hyperthermia, arrhythmias, MI, stroke, rhabdomyolysis. --- If you want, I can now: * Convert **some/all of these into 20–30 hard HTML+CSS+JS MCQs** on sympathomimetics * Structure them for your **medicalmcq.erroron.space** JSON format * Or make a **single-page quiz file** you can directly upload. Tell me: **“make 25 hard MCQs in one HTML file on sympathomimetics from these cases”** and I’ll build it.