Pharmacology Drug Classes and Mechanisms Summary

Posted on Feb 16, 2026 in Biotechnology

NSAIDs: Pain Relief and Inflammation Reduction

NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) are a class of meds that reduce inflammation, pain, and fever. They’re like the ultimate pain relief squad.

Classification

  • Non-selective COX inhibitors: Aspirin, Ibuprofen, Diclofenac, Naproxen
  • COX-2 selective inhibitors: Celecoxib, Etoricoxib

Pharmacology of Aspirin

  • Mechanism: Aspirin irreversibly inhibits COX-1 and COX-2 enzymes, reducing prostaglandin synthesis, which leads to decreased pain, inflammation, and fever.

Anti-Hypertensive Drug Classification

  • Diuretics: Thiazides, Loop diuretics, Potassium-sparing
  • Beta blockers: e.g., Metoprolol, Atenolol
  • ACE inhibitors: e.g., Lisinopril, Enalapril
  • Angiotensin receptor blockers (ARBs): e.g., Losartan, Valsartan
  • Calcium channel blockers (CCBs): e.g., Amlodipine, Verapamil
  • Alpha blockers: e.g., Prazosin
  • Vasodilators: e.g., Hydralazine, Minoxidil

Calcium Channel Blockers

  • Mechanism of Action (MOA): Block L-type calcium channels in vascular smooth muscle and heart, leading to vasodilation and reduced peripheral resistance.
  • Examples: Amlodipine, Verapamil, Nifedipine

Nitrates MOA

  • MOA: Release nitric oxide (NO), causing vasodilation (mainly venous), reducing preload and myocardial O2 demand.

Management of Hypertension in Pregnancy

  • Mild HTN: Monitor closely, lifestyle changes.
  • Moderate to severe HTN:
    • First-line: Methyldopa, Labetalol
    • Other options: Nifedipine, Hydralazine
  • Avoid: ACE inhibitors, ARBs

Drugs Acting on Uterus

  • Uterine stimulants (Oxytocics): Oxytocin, Prostaglandins, Ergot alkaloids
  • Uterine relaxants (Tocolytics):
    • Beta-2 agonists (e.g., Salbutamol)
    • Calcium channel blockers (e.g., Nifedipine)
    • Oxytocin receptor antagonists (e.g., Atosiban)

Pharmacology of Oxytocin

  • MOA: Stimulates oxytocin receptors in uterine muscle, increasing intracellular calcium and uterine contractions.
  • Uses:
    • Labor induction/augmentation
    • Postpartum hemorrhage control

Oral Contraceptives Classification

  • Combined Oral Contraceptives (COCs): Estrogen + Progestin (e.g., Ethinyl estradiol + Levonorgestrel)
  • Progestin-only Pills (POPs): Only progestin (e.g., Norethindrone)

Pharmacology of COCs

  • MOA: Suppress LH/FSH, inhibit ovulation; thicken cervical mucus; alter endometrium.
  • Common Uses: Pregnancy prevention, Menstrual regulation, Acne/hirsutism treatment

Oral Hypoglycemic Agents Classification

  • Biguanides: e.g., Metformin
  • Sulfonylureas: e.g., Glibenclamide, Gimepiride
  • Meglitinides: e.g., Repaglinide
  • Thiazolidinediones: e.g., Pioglitazone
  • DPP-4 inhibitors: e.g., Sitagliptin
  • SGLT2 inhibitors: e.g., Dapagliflozin
  • Alpha-glucosidase inhibitors: e.g., Acarbose

Pharmacology Highlights (Hypoglycemics)

  • Metformin: Decreases hepatic glucose production; increases insulin sensitivity.
  • Sulfonylureas: Stimulate insulin release from pancreas.
  • DPP-4 inhibitors: Increase incretin levels, enhance insulin secretion.
  • SGLT2 inhibitors: Block glucose reabsorption in kidneys, increase glucose excretion.

Autacoids

  • Definition: Autacoids are locally acting chemical messengers that have potent biological effects.
  • Classification:
    • Amine autacoids: Histamine, Serotonin
    • Peptide autacoids: Angiotensin, Bradykinin
    • Lipid autacoids: Prostaglandins, Leukotrienes

H1 Receptor Antagonists

  • Definition: Drugs that block histamine H1 receptors, used mainly for allergies.
  • Examples: Diphenhydramine, Loratadine
  • Uses: Allergic rhinitis, itching, urticaria, motion sickness
  • Effects: Reduce allergic symptoms; 1st gen can cause sedation.

Diuretics Classification

  • Thiazide diuretics: e.g., Hydrochlorothiazide
    • MOA: Inhibit Na-Cl cotransport in DCT
  • Loop diuretics: e.g., Furosemide
    • MOA: Inhibit Na-K-2Cl cotransport in Loop of Henle
  • Potassium-sparing diuretics: e.g., Spironolactone, Amiloride
    • MOA: Block aldosterone or ENaC
  • Carbonic anhydrase inhibitors: e.g., Acetazolamide
    • MOA: Inhibit CA in PCT
  • Osmotic diuretics: e.g., Mannitol
    • MOA: Increase osmotic pressure in tubules

Diuretic Pharmacology Highlights

  • Thiazides: $\downarrow$BP, $\downarrow$Ca excretion
  • Loop diuretics: Potent diuresis, used in edema, acute pulmonary edema
  • K-sparing: $\downarrow$K loss, used with other diuretics or in hyperaldosteronism

Arachidonic Acid Pathway

  • Arachidonic acid is released from membrane phospholipids by phospholipase A2.
  • AA is metabolized via:
    • Cyclooxygenase: $\rightarrow$ Prostaglandins, Thromboxanes
    • Lipoxygenase: $\rightarrow$ Leukotrienes
    • Cytochrome P450: $\rightarrow$ Epoxyeicosatrienoic acids

Prostaglandins

  • Physiological roles:
    • PGE2: Pain, fever, inflammation; gastric protection
    • PGI2: Vasodilation, inhibits platelet aggregation
    • TXA2: Vasoconstriction, platelet aggregation
  • Psychological roles: Involved in mood regulation, stress response

Bioassay Principles

  • Definition: Quantitative measurement of a drug’s potency using biological responses.
  • Principle: Compares test drug’s effect with a standard drug on a biological system.

Types of Bioassays

  • In vivo: In living organisms
  • In vitro: In isolated tissues/cells
  • Ex vivo: Tissues from animals

Bioassay Examples

  • Insulin:
    • Method: Rabbit blood sugar $\downarrow$ or rat diaphragm glucose uptake
    • Principle: Insulin’s hypoglycemic effect or glucose uptake in tissues
  • Oxytocin:
    • Method: Rat uterus contraction or milk ejection in lactating rat
    • Principle: Oxytocin stimulates uterine contractions or milk ejection

Anti-Hyperlipidemic Agents

  • Definition: Drugs that lower lipid levels in blood.
  • Classification:
    • Statins: e.g., Atorvastatin
    • Fibrates: e.g., Fenofibrate
    • Bile acid sequestrants: e.g., Cholestyramine
    • Cholesterol absorption inhibitors: e.g., Ezetimibe
    • PCSK9 inhibitors: e.g., Alirocumab

HMG-CoA Reductase Inhibitors (Statins)

  • MOA: Inhibit HMG-CoA reductase, a key enzyme in cholesterol synthesis in the liver.
  • Effect: $\downarrow$Cholesterol synthesis, $\uparrow$LDL receptor expression, $\downarrow$LDL cholesterol.
  • Examples: Atorvastatin, Rosuvastatin, Simvastatin

MOA of Statins

  • Reduce hepatic cholesterol synthesis.
  • $\uparrow$LDL receptor expression $\rightarrow \downarrow$LDL cholesterol in blood.

Thyroid Drugs

  • Thyroid hormones: e.g., Levothyroxine, Liothyronine for hypothyroidism.
  • Anti-thyroid drugs: e.g., Methimazole, Propylthiouracil for hyperthyroidism.

Thioamides

  • MOA: Inhibit thyroid peroxidase, blocking:
    • Iodination of tyrosine
    • Coupling of iodotyrosines to form T3/T4
  • Examples: Methimazole, Propylthiouracil

Drugs for Congestive Heart Failure (CHF)

  • Diuretics: e.g., Furosemide
  • ACE inhibitors: e.g., Lisinopril
  • Beta blockers: e.g., Metoprolol
  • ARBs: e.g., Losartan
  • ARNIs: e.g., Sacubitril/valsartan
  • Inotropes: e.g., Digoxin

Drugs for Angina Pectoris

  • Nitrates: e.g., Nitroglycerin
  • Beta blockers: e.g., Metoprolol
  • Calcium channel blockers: e.g., Amlodipine
  • Anti-platelets: e.g., Aspirin