Pharmacology Made Simple

Pharmacology: Three Types

1. Systemic Pharmacology:
   • Focuses on the study of drugs that affect the entire body through the bloodstream, often targeting multiple organs and systems.
2. Ans Pharmacology (Autonomic Nervous System):
   • Cholinergic:
     • Agonists: Drugs that mimic the action of acetylcholine (e.g., muscarinic agonists).
     • Antagonists: Drugs that block acetylcholine receptors (e.g., atropine).
   • Adrenergic:
     • Agonists: Drugs that stimulate adrenergic receptors (e.g., beta-agonists).
     • Antagonists: Drugs that block adrenergic receptors (e.g., beta-blockers).
3. Antimicrobial Pharmacology:
   • Focuses on drugs that are used to treat infections by targeting microorganisms like bacteria, viruses, fungi, and parasites.

1. CVS Pharmacology – Anti-Hypertensive (Anti-HTN)

1. ACE Inhibitors (pril):
   • Side Effects: Dry cough, angioedema
   • Contraindication: Not to be used in pregnancy
2. Spironolactone:
   • Side Effects: Gynecomastia, hyperkalemia
3. Hydralazine:
   • Side Effect: Drug-induced lupus erythematosus (SLE)
4. Alpha-Methyl Dopa:
   • Safe for use during pregnancy
5. Procainamide
6. Isoniazid

2. Gestational Hypertension (HTN) + Agents Acting on Beta and Alpha Receptors

1. Labetalol
2. Carvedilol
3. Short-acting Intraoperatively:
   • Esmolol
4. Dyslipidemia
   • Metoprolol
5. Digoxin:
   • Action: Inhibits the Na+/K+ pump
   • Effect: Leads to increased potassium levels and increased contractility of the heart.

3. Lipid-Lowering Agents

1. Statins:
   • MOA: Inhibit HMG-CoA reductase
   • Side Effects (S/E):
     • Hepatotoxicity
     • Rhabdomyolysis
     • Combined with fibrates: Increased risk of gallstones
2. Niacin (Vitamin B3):
   • MOA: Inhibits liver production of VLDL (very low-density lipoproteins), leading to a reduction in triglycerides and LDL cholesterol.
   • Effect: Increases HDL cholesterol (good cholesterol).
   • Side Effects (S/E):
     • Flushing (due to vasodilation)
     • Hepatotoxicity (in high doses)
     • Hyperglycemia (can worsen diabetes)

4. Antiarrhythmic Medications

1. Na Channel Blockers:
   • Class 1a:
     • Quinidine: Causes cinchonism (ringing in the ears, vertigo, headache)
     • Procainamide: Can cause SLE (Systemic Lupus Erythematosus)
     • Disopyramide: Can lead to heart failure (HF) edema
   • Class 1b:
     • Lidocaine: Used as a local anesthetic
     • Phenytoin: Used for epilepsy, can cause gingival hyperplasia
   • Class 1c:
     • Propafenone: Contraindicated after MI (heart attack)
2. K Channel Blockers:
   • Amiodarone: Used for AIDS treatment, has various arrhythmic indications
   • Ibutilide: Used for atrial arrhythmias
3. Ca Channel Blockers:
   • Diltiazem
   • Verapamil

5. Thyroid Drugs

1. Hyperthyroidism:
   • PTU (Propylthiouracil): Preferred in 1st trimester of pregnancy
   • Methimazole: Used after the 1st trimester of pregnancy
2. Hypothyroidism:
   • Levothyroxine (synthetic T4)

6. Diabetes Mellitus (DM)

1. Insulin:
   • Side Effects (S/E):
     • Hypoglycemia
     • Lipodystrophy
2. Oral Agents
   • Biguanides:
     • Metformin: First-line for DM2 (especially with obesity)
     • Contraindicated in renal failure
3. Sulfonylureas:
   • Glyburide, Tolbutamide
   • Side Effects (S/E):
     • Hypoglycemia
     • Weight gain
4. Thiazolidinediones (TZDs):
   • Pioglitazone: Can increase DM2 risk and risk of fractures
5. SGLT2 Inhibitors:
   • Empagliflozin
   • Dapagliflozin
   • Increase glucose excretion in urine, leading to reduced blood glucose levels.

7. GIT

Acid Suppression Therapy

1. Proton Pump Inhibitors (PPI):
   • Used for: Zollinger-Ellison syndrome
2. H2 Blockers:
   • Cimetidine:
     • Side Effect (S/E): Gynecomastia
3. Prostaglandin Analogues:
   • Misoprostol:
     • Used for NSAID-induced gastric ulcers
4. Antacids:
   • Aluminum Hydroxide:
     • Side Effect (S/E): Constipation
5. Magnesium Hydroxide:
   • Side Effect (S/E): Diarrhea

8. Antiemetic Medications

1. Ondansetron:
   • MOA: 5HT3 receptor inhibitor
   • Effect: Decreases vomiting and reduces chemotherapy-induced vomiting.
2. Metoclopramide:
   • MOA: Inhibits dopamine receptors in the chemoreceptor trigger zone
   • Side Effects: Parkinson-like symptoms
   • Use: In diabetic gastroparesis
3. Aprepitant:
   • MOA: Acts on NK-1 receptor (neurokinin)
   • Used to control nausea and vomiting, especially related to chemotherapy.
4. Domperidone:
   • MOA: Dopamine antagonist, used to treat nausea and vomiting.

Here are other materials for NLE NRE step 1

9. Laxatives

• Lactulose:
  • Use: Also used in hepatic encephalopathy to reduce ammonia levels in the blood.

10. Antidiarrheal Medications

• Metronidazole:
  • Use: Primarily an antibiotic, used for infections such as Clostridium difficile or giardiasis. It is not a typical antidiarrheal, but it can help treat infections that cause diarrhea.
• Loperamide:
  • Use: A common antidiarrheal that works by slowing down gut motility, helping reduce the frequency of diarrhea.

11. Parasympathetic vs Sympathetic Nervous System

Feature	Parasympathetic	Sympathetic
Preganglionic Fibers	Long and attach near target organ	Short, and postganglionic fibers are long
Postganglionic Fibers	Short, attach to M1, M2, M3 receptors	Long
Neurotransmitter	Acetylcholine (ACh)	Norepinephrine (NE) and Epinephrine (Epi), except in sweat glands (ACh)
Cranial Nerves Involved	CN 3, CN 7, CN 9, CN 10	N/A
Receptors	M1, M2, M3 receptors	M3 receptors in adrenal medulla

12. Acetylcholine (ACh) Receptors

Receptor Type	Location
Nn (Nicotine)	Autonomic ganglia, adrenal medulla
Nm (Nicotine)	Neuromuscular junction of skeletal muscle
M1	Activates in certain tissues
M2	Inhibits (primarily in heart tissue)
M3	Activates in various organs (e.g., smooth muscle)
M4, M5	Inhibitory effects, specific areas of brain

13. Micturition Control

Sympathetic	Parasympathetic	Medications	Effect
Alpha 1, Beta 3	M3	Bethanechol (Muscarinic Agonist)	Void increases (promotes urination)
Hypogastric Nerve	Activated by Bethanechol	Oxybutynin (Muscarinic Antagonist)	Decreases urgency incontinence and detrusor overactivity (relieves urgency)
Effect: Increase urinary retention		Mirabegron (Sympathomimetic)	Increases bladder capacity (used for urgency incontinence)
		Tamsulosin (Alpha Blocker)	Reduces urinary obstruction (used for BPH – benign prostatic hyperplasia)
		Muscarinic Agonist: Bethanechol	Increases bladder emptying, urinary retention relief

Receptors & Effects:

Receptor	Effect
Alpha 1	Vasoconstriction, smooth muscle contraction
Alpha 2	Inhibition
Beta 1	Increased heart rate (HR)
Beta 2	Bronchodilation
Beta 3	Increased lipolysis, bladder relaxation

Check your NRE Step 1 result after completing the exam.