# 11. Principles of General Pharmacology (Overview)

**Definition:** Science dealing with drugs and their interaction with the living system.

- **Drug definition:** Any chemical substance that produces a biological effect on living tissue when administered.
- **Drug dosage forms:** Tablet, capsule, syrup, injection, ointment, suppository, inhaler, etc. - chosen based on route, stability, and desired onset of action.
- **Route of drug administration:** Oral, sublingual, rectal, parenteral (IV/IM/SC), topical, inhalational, transdermal - each with different onset, bioavailability, and convenience.
- **Pharmacokinetics (PK) - what body does to drug:** Absorption, Distribution, Metabolism, Excretion (ADME).
- **Pharmacodynamics (PD) - what drug does to body:** Mechanism of action, receptor binding (agonist/antagonist), dose-response relationship.
- **Drug dose:** Amount of drug needed to produce a desired effect; depends on age, weight, route, and individual factors.
- **Principles of drug action / Mechanism of drug action:** Most drugs act via receptors (GPCRs, ion channels, enzymes, nuclear receptors); some act by physical/chemical means (antacids, osmotic agents).
- **Bioavailability:** Fraction of administered drug that reaches systemic circulation unchanged; IV = 100%; oral is reduced due to first-pass metabolism.

**Ayurvedic correlation (exam value-add):** Vipaka relates to post-absorptive drug transformation (~metabolism); Prabhava relates to specific mechanism of action; Virya relates to potency/intensity of action; Rasa relates to the initial local effect.

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## 11.1 Drugs Acting on Central Nervous System

### A. General Anaesthetics
- **Definition:** Drugs that produce reversible loss of consciousness, sensation, and reflexes, allowing surgery without pain.
- **Classification:** Inhalational agents; Intravenous agents.
- **Mechanism:** Inhalational - depress CNS by altering neuronal membrane function, producing stages of anaesthesia (analgesia to excitement to surgical anaesthesia to medullary paralysis). IV agents - rapidly depress CNS activity for quick onset of unconsciousness.
- **Examples:** Inhalational: Halothane, Isoflurane, Nitrous oxide. IV: Thiopentone, Propofol, Ketamine.
- **Clinical use:** Induction and maintenance of surgical anaesthesia.
- **Exam point:** Halothane can cause hepatotoxicity ("halothane hepatitis"); Ketamine causes dissociative anaesthesia with hallucinations.

### B. Sedative-Hypnotics
- **Definition:** Drugs that calm (sedate) at low dose and induce sleep (hypnosis) at higher dose.
- **Classification:** Benzodiazepines; Barbiturates; Newer non-benzodiazepine hypnotics (Z-drugs).
- **Mechanism:** Benzodiazepines enhance GABA action in brain. Barbiturates cause generalized CNS depression via GABA (stronger, less safe). Z-drugs act selectively on GABA receptors for sleep with fewer side effects.
- **Examples:** Benzodiazepines: Diazepam, Lorazepam, Alprazolam. Barbiturates: Phenobarbitone, Thiopentone. Z-drugs: Zolpidem, Zopiclone.
- **Clinical use:** Insomnia, anxiety, pre-anaesthetic sedation, seizure control (some).
- **Exam point:** Barbiturates have low safety margin (respiratory depression, dependence); Benzodiazepine overdose reversed by Flumazenil.

### C. Antiepileptics
- **Definition:** Drugs that control or prevent seizures/convulsions.
- **Classification:** Sodium channel blockers; GABA enhancers; Broad-spectrum agents.
- **Mechanism:** Sodium channel blockers stabilize neuronal membrane by blocking excess sodium influx. GABA enhancers increase inhibitory GABA action. Broad-spectrum agents combine multiple actions.
- **Examples:** Sodium channel blockers: Phenytoin, Carbamazepine. GABA enhancers: Phenobarbitone, Clonazepam. Broad-spectrum: Sodium valproate, Levetiracetam.
- **Clinical use:** Epilepsy (generalized and partial seizures), status epilepticus.
- **Exam point:** Phenytoin causes gum hyperplasia; Valproate is teratogenic (avoid in pregnancy).

### D. Antiparkinsonian Drugs
- **Definition:** Drugs used to relieve symptoms of Parkinson's disease caused by dopamine deficiency in brain.
- **Classification:** Dopamine precursors/agonists; Anticholinergics; MAO-B inhibitors.
- **Mechanism:** Dopamine precursor/agonists restore/mimic dopamine activity. Anticholinergics block excess cholinergic activity from dopamine lack. MAO-B inhibitors reduce dopamine breakdown.
- **Examples:** Levodopa (with Carbidopa), Bromocriptine; Trihexyphenidyl; Selegiline.
- **Clinical use:** Parkinson's disease (tremor, rigidity, bradykinesia).
- **Exam point:** Levodopa always combined with Carbidopa to reduce peripheral side effects and increase brain availability.

### E. Antidepressants
- **Definition:** Drugs used to relieve depression by increasing brain monoamine (serotonin/noradrenaline) levels.
- **Classification:** Tricyclic antidepressants (TCAs); SSRIs; MAOIs.
- **Mechanism:** TCAs block reuptake of serotonin/noradrenaline. SSRIs selectively block serotonin reuptake. MAOIs inhibit enzyme that breaks down monoamines.
- **Examples:** TCAs: Imipramine, Amitriptyline. SSRIs: Fluoxetine, Sertraline. MAOIs: Phenelzine.
- **Clinical use:** Major depressive disorder, anxiety disorders, chronic pain (TCAs).
- **Exam point:** SSRIs preferred first-line (fewer side effects than TCAs); MAOIs need dietary tyramine restriction (cheese reaction).

### F. Antianxiety (Anxiolytic) Drugs
- **Definition:** Drugs used to reduce excessive anxiety without much sedation.
- **Classification:** Benzodiazepines; Non-benzodiazepine anxiolytics.
- **Mechanism:** Benzodiazepines enhance GABA-mediated inhibition. Buspirone acts on serotonin receptors.
- **Examples:** Diazepam, Alprazolam, Lorazepam; Buspirone.
- **Clinical use:** Generalized anxiety disorder, panic disorder, pre-operative anxiety.
- **Exam point:** Long-term benzodiazepine use causes tolerance/dependence; Buspirone has no dependence liability but slower onset.

### G. Opioid Analgesics
- **Definition:** Drugs derived from/related to opium that relieve severe pain by acting on opioid receptors.
- **Classification:** Natural opioids; Synthetic/semisynthetic opioids; Opioid antagonists.
- **Mechanism:** Act on mu opioid receptors in CNS to block pain transmission. Antagonists block opioid receptors, reversing opioid effects.
- **Examples:** Morphine, Codeine; Pethidine, Tramadol, Fentanyl; Naloxone (antagonist).
- **Clinical use:** Severe pain, cough suppression (codeine), diarrhoea (some).
- **Exam point:** Morphine causes respiratory depression and constipation; overdose reversed by Naloxone; risk of dependence with prolonged use.

## 11.2 Drugs Acting on Peripheral (Somatic) Nervous System

### A. Skeletal Muscle Relaxants
- **Definition:** Drugs that reduce skeletal muscle tone/contraction, used to relax muscles during surgery or spasm.
- **Classification:** Peripherally acting (neuromuscular blockers); Centrally acting muscle relaxants.
- **Mechanism:** Neuromuscular blockers block acetylcholine at neuromuscular junction, causing paralysis. Centrally acting relaxants act on brain/spinal cord to reduce muscle tone.
- **Examples:** Succinylcholine, Vecuronium, Tubocurarine; Baclofen, Diazepam, Tizanidine.
- **Clinical use:** Muscle relaxation during surgery/intubation; muscle spasm, spasticity.
- **Exam point:** Neuromuscular blockers cause complete paralysis including respiratory muscles - require ventilatory support; reversed by neostigmine (non-depolarizing type).

### B. Local Anaesthetics
- **Definition:** Drugs that produce reversible loss of sensation in a localized area without loss of consciousness.
- **Classification:** Ester type; Amide type.
- **Mechanism:** Block sodium channels in nerve fibres, preventing impulse conduction.
- **Examples:** Ester: Procaine, Benzocaine. Amide: Lidocaine, Bupivacaine.
- **Clinical use:** Minor surgery, dental procedures, spinal/epidural anaesthesia, infiltration anaesthesia.
- **Exam point:** Adrenaline often added to prolong action and reduce bleeding - avoid in extremities (fingers, toes, ear, nose) due to ischemia risk.

## 11.3 Autacoids and Related Drugs

### NSAIDs / Antipyretic-Analgesic Drugs
- **Definition:** Drugs that relieve pain, fever, and inflammation by inhibiting prostaglandin synthesis.
- **Classification:** Non-selective COX inhibitors; Selective COX-2 inhibitors; Para-aminophenol derivative (Paracetamol).
- **Mechanism:** Non-selective COX inhibitors block COX-1 and COX-2, reducing prostaglandins. COX-2 selective drugs block mainly COX-2, sparing COX-1 (protective in stomach). Paracetamol inhibits prostaglandin synthesis mainly in CNS.
- **Examples:** Aspirin, Ibuprofen, Diclofenac; Celecoxib, Etoricoxib; Paracetamol.
- **Clinical use:** Fever, mild-moderate pain, inflammatory conditions (arthritis); low-dose Aspirin as antiplatelet.
- **Exam point:** Non-selective NSAIDs cause gastric ulceration/bleeding; Aspirin contraindicated in children with viral fever (Reye's syndrome); Paracetamol overdose causes hepatotoxicity.

## 11.4 Drugs for Respiratory Disorders

### A. Bronchodilators
- **Definition:** Drugs that relax bronchial smooth muscle to widen airways, used mainly in asthma/COPD.
- **Classification:** Beta-2 agonists; Anticholinergics; Methylxanthines.
- **Mechanism:** Beta-2 agonists stimulate beta-2 receptors causing bronchodilation. Anticholinergics block muscarinic receptors reducing bronchoconstriction. Methylxanthines relax bronchial smooth muscle with mild anti-inflammatory action.
- **Examples:** Salbutamol, Formoterol, Terbutaline; Ipratropium bromide; Theophylline.
- **Clinical use:** Bronchial asthma, COPD, acute bronchospasm.
- **Exam point:** Salbutamol can cause tremor/tachycardia; Theophylline has narrow safety margin.

### B. Aerosols/Inhalants
- **Definition:** Drug delivery method where medication is inhaled as fine particles/mist directly into respiratory tract.
- **Classification:** Metered dose inhalers (MDI); Dry powder inhalers (DPI); Nebulizers.
- **Mechanism:** Deliver drug directly to airway mucosa, giving faster onset and fewer systemic side effects than oral route.
- **Examples:** Salbutamol inhaler, Budesonide inhaler, Beclomethasone inhaler.
- **Clinical use:** Asthma and COPD maintenance and acute relief therapy.
- **Exam point:** Inhaled route reduces systemic side effects vs oral drugs; proper inhaler technique essential.

### C. Expectorants
- **Definition:** Drugs that increase/thin bronchial secretions to facilitate easier expulsion of sputum.
- **Classification:** Mucolytics; Bronchial secretion stimulants.
- **Mechanism:** Mucolytics break down mucus structure reducing viscosity. Secretion stimulants increase watery secretion.
- **Examples:** Bromhexine, Ambroxol, Acetylcysteine; Potassium iodide, Guaifenesin.
- **Clinical use:** Productive cough with thick sputum (bronchitis, COPD).
- **Exam point:** Should not be combined with cough suppressants - can cause mucus retention.

### D. Antitussive Drugs
- **Definition:** Drugs that suppress the cough reflex, used for dry/irritating non-productive cough.
- **Classification:** Centrally acting (opioid); Centrally acting (non-opioid); Peripherally acting/demulcents.
- **Mechanism:** Centrally acting drugs suppress cough centre in medulla. Peripherally acting agents soothe irritated throat mucosa.
- **Examples:** Codeine (opioid); Dextromethorphan (non-opioid); Lozenges, honey-based syrups (demulcent).
- **Clinical use:** Dry, irritating, non-productive cough.
- **Exam point:** Codeine can cause sedation, constipation, dependence; contraindicated in productive cough.

## 11.5 Cardiovascular Drugs

### A. Antihypertensive Drugs
- **Definition:** Drugs used to lower elevated blood pressure and maintain it within normal range.
- **Classification:** Diuretics; Beta-blockers; ACE inhibitors/ARBs; Calcium channel blockers.
- **Mechanism:** Diuretics reduce blood volume. Beta-blockers reduce heart rate/cardiac output. ACE inhibitors/ARBs block angiotensin action. Calcium channel blockers relax vessel walls.
- **Examples:** Hydrochlorothiazide, Furosemide; Atenolol, Metoprolol; Enalapril, Losartan; Amlodipine, Nifedipine.
- **Clinical use:** Essential/secondary hypertension, prevention of stroke/heart disease.
- **Exam point:** ACE inhibitors cause dry cough; contraindicated in pregnancy.

### B. Antianginal Drugs
- **Definition:** Drugs used to relieve or prevent angina pectoris.
- **Classification:** Nitrates; Beta-blockers; Calcium channel blockers.
- **Mechanism:** Nitrates dilate veins/coronary vessels, reducing cardiac workload. Beta-blockers reduce myocardial oxygen demand. Calcium channel blockers dilate coronary arteries.
- **Examples:** Glyceryl trinitrate, Isosorbide dinitrate; Atenolol, Propranolol; Amlodipine, Verapamil.
- **Clinical use:** Angina pectoris (stable/unstable), acute anginal attack (sublingual nitrates).
- **Exam point:** Sublingual Nitroglycerin gives rapid relief in acute angina; side effects include headache and postural hypotension.

## 11.6 Drugs Acting on Kidney: Diuretics

- **Definition:** Drugs that increase urine output by promoting excretion of sodium/water from kidney, used for fluid overload/oedema and BP control.

### A. Loop Diuretics
- **Site:** Thick ascending limb of loop of Henle. **Mechanism:** Inhibit Na-K-Cl reabsorption (most potent).
- **Examples:** Furosemide, Torsemide. **Use:** Acute pulmonary oedema, heart failure, severe oedema.
- **Exam point:** Can cause hypokalemia and ototoxicity at high doses.

### B. Thiazide Diuretics
- **Site:** Distal convoluted tubule. **Mechanism:** Inhibit Na-Cl reabsorption (moderate diuresis).
- **Examples:** Hydrochlorothiazide, Chlorthalidone. **Use:** First-line for mild-moderate hypertension.
- **Exam point:** Can cause hypokalemia and hyperuricemia (caution in gout).

### C. Potassium-Sparing Diuretics
- **Site:** Collecting duct/distal tubule. **Mechanism:** Block sodium reabsorption without potassium loss.
- **Examples:** Spironolactone, Amiloride. **Use:** Combined with other diuretics to prevent K+ loss; heart failure.
- **Exam point:** Risk of hyperkalemia, especially with ACE inhibitors/ARBs or renal impairment.

### D. Osmotic Diuretics
- **Site:** Proximal tubule/loop of Henle. **Mechanism:** Increase osmotic pressure in tubules, pulling water into urine.
- **Examples:** Mannitol. **Use:** Cerebral oedema, raised intracranial/intraocular pressure.
- **Exam point:** Contraindicated in heart failure/anuria (fluid overload risk).

### E. Carbonic Anhydrase Inhibitors
- **Site:** Proximal convoluted tubule. **Mechanism:** Inhibit carbonic anhydrase, reducing bicarbonate/sodium reabsorption.
- **Examples:** Acetazolamide. **Use:** Glaucoma, mild diuresis, altitude sickness prevention.
- **Exam point:** Can cause metabolic acidosis with prolonged use.

## 11.7 Drugs Affecting Blood

### A. Haematinics
- **Definition:** Drugs used to increase haemoglobin/RBC formation in anaemia.
- **Classification:** Iron preparations - provide substrate for Hb synthesis (Ferrous sulphate, Ferrous fumarate, Iron sorbitol). Vitamin B12 - needed for DNA synthesis in RBC maturation (Cyanocobalamin, Hydroxocobalamin). Folic acid - co-factor for DNA synthesis (Folic acid, Folinic acid).
- **Clinical use:** Iron deficiency anaemia; Pernicious/megaloblastic anaemia (B12); pregnancy (folic acid).
- **Exam point:** Iron therapy causes black stools, gastric irritation, constipation; B12 must be given with folic acid in megaloblastic anaemia.

### B. Coagulants (Haemostatic agents)
- **Definition:** Drugs that promote blood clotting/stop bleeding.
- **Classification:** Vitamin K - needed for clotting factors II, VII, IX, X synthesis. Fibrinolytic inhibitors (Tranexamic acid, Aminocaproic acid). Topical haemostatics (Thrombin, Fibrin glue, Ethamsylate).
- **Clinical use:** Vitamin K deficiency bleeding, warfarin overdose reversal, menorrhagia, surgical bleeding.
- **Exam point:** Vitamin K is fat-soluble, needs bile for absorption; used to reverse warfarin toxicity.

### C. Anticoagulants
- **Definition:** Drugs that prevent/delay blood clotting.
- **Classification:** Heparin (injectable) - activates antithrombin III, inhibits thrombin/factor Xa, immediate action. Vitamin K antagonists (Warfarin, Acenocoumarol) - inhibit hepatic synthesis of clotting factors. DOACs (Rivaroxaban, Apixaban, Dabigatran) - directly inhibit factor Xa/thrombin.
- **Clinical use:** DVT, pulmonary embolism, atrial fibrillation, prosthetic heart valves.
- **Exam point:** Heparin monitored by aPTT, Warfarin by INR/PT; Warfarin teratogenic; main side effect = bleeding.

### D. Hypolipidaemic Drugs
- **Definition:** Drugs used to lower elevated blood lipid levels.
- **Classification:** Statins (Atorvastatin, Rosuvastatin) - inhibit HMG-CoA reductase. Fibrates (Fenofibrate, Gemfibrozil) - increase lipoprotein lipase activity. Bile acid sequestrants (Cholestyramine). Others - Niacin, Ezetimibe.
- **Clinical use:** Hyperlipidaemia, prevention of atherosclerosis/coronary heart disease.
- **Exam point:** Statins risk myopathy/rhabdomyolysis and deranged liver enzymes; best taken at night; avoid in pregnancy.

## 11.8 Gastrointestinal Drugs

### A. Antacids
- **Definition:** Drugs that neutralize gastric acid to relieve hyperacidity.
- **Classification:** Systemic antacid (Sodium bicarbonate) - absorbed, may cause alkalosis. Non-systemic antacids (Magnesium hydroxide, Aluminium hydroxide, Calcium carbonate) - not absorbed.
- **Clinical use:** Peptic ulcer, GERD, dyspepsia/hyperacidity.
- **Exam point:** Magnesium salts cause diarrhoea; Aluminium salts cause constipation; often combined.

### B. Carminatives
- **Definition:** Agents that help expel gas from GI tract, relieving flatulence/bloating.
- **Examples:** Peppermint oil, Cardamom, Ajwain, Fennel, Asafoetida (Hing).
- **Clinical use:** Flatulence, colic, indigestion.
- **Exam point:** Mostly herbal/aromatic; safe, widely used in infantile colic.

### C. Digestants
- **Definition:** Substances that aid digestion by supplementing digestive enzymes.
- **Examples:** Pepsin, Pancreatin, Papain.
- **Clinical use:** Chronic pancreatitis, enzyme deficiency states, dyspepsia.
- **Exam point:** Given with meals for optimal action.

### D. Antiemetics
- **Definition:** Drugs used to prevent or relieve nausea and vomiting.
- **Classification:** Antihistamines (Promethazine, Doxylamine) - block H1 receptors. D2 antagonists (Metoclopramide, Domperidone) - block D2 receptors in CTZ. 5-HT3 antagonists (Ondansetron, Granisetron) - block serotonin receptors. Anticholinergics (Hyoscine) - motion sickness.
- **Clinical use:** Motion sickness, chemotherapy-induced vomiting, pregnancy nausea, post-op vomiting.
- **Exam point:** Ondansetron is drug of choice for chemo-induced vomiting; Metoclopramide can cause extrapyramidal side effects.

### E. Laxatives
- **Definition:** Drugs that promote bowel evacuation/relieve constipation.
- **Classification:** Bulk-forming (Psyllium/Isabgol, Bran). Osmotic (Lactulose, Magnesium sulphate). Stimulant/irritant (Senna, Bisacodyl, Castor oil). Stool softeners (Liquid paraffin, Docusate).
- **Clinical use:** Constipation, bowel preparation before surgery/colonoscopy.
- **Exam point:** Chronic stimulant use causes laxative dependence/atonic colon; avoid castor oil in pregnancy.

### F. Antidiarrhoeal Drugs
- **Definition:** Drugs used to control diarrhoea by decreasing intestinal motility/fluid loss.
- **Classification:** Opioid derivatives (Loperamide, Diphenoxylate). Adsorbents (Kaolin, Pectin, Activated charcoal). ORS - fluid/electrolyte replacement.
- **Clinical use:** Acute/chronic diarrhoea; ORS mainstay in acute gastroenteritis.
- **Exam point:** ORS/fluid replacement more important than antimotility drugs, especially in children; Loperamide avoided in dysentery.

### G. Hepatoprotective Drugs
- **Definition:** Drugs/agents that protect liver cells from damage and support regeneration.
- **Examples:** Silymarin - antioxidant, stabilizes hepatocyte membrane. N-acetylcysteine (NAC) - replenishes glutathione. Ursodeoxycholic acid - improves bile flow.
- **Clinical use:** Toxic/drug-induced hepatitis, chronic liver disease, paracetamol overdose (NAC).
- **Exam point:** NAC is antidote of choice in paracetamol-induced hepatotoxicity.

## 11.9 Antibacterial Drugs

### A. Antibiotics - Major Classes
- **Penicillins** - inhibit bacterial cell wall synthesis (bactericidal). Examples: Amoxicillin, Ampicillin, Benzylpenicillin. Use: Streptococcal infections, pneumonia, UTI. Exam point: Hypersensitivity/anaphylaxis risk - always ask allergy history.
- **Cephalosporins** - inhibit cell wall synthesis, broader spectrum. Examples: Cefixime, Ceftriaxone, Cephalexin. Use: Respiratory, urinary, skin infections, surgical prophylaxis. Exam point: Partial cross-allergy with penicillins.
- **Macrolides** - inhibit protein synthesis (50S ribosomal subunit). Examples: Erythromycin, Azithromycin, Clarithromycin. Use: Respiratory infections, atypical pneumonia, penicillin-allergic patients. Exam point: Azithromycin - once-daily dosing, good tissue penetration.
- **Fluoroquinolones** - inhibit DNA gyrase/topoisomerase. Examples: Ciprofloxacin, Levofloxacin, Norfloxacin. Use: UTI, typhoid, GI/respiratory infections. Exam point: Avoid in children/pregnant women - cartilage/tendon damage risk.
- **Aminoglycosides** - inhibit protein synthesis (30S subunit), bactericidal. Examples: Gentamicin, Streptomycin, Amikacin. Use: Severe Gram-negative infections, TB (streptomycin). Exam point: Nephrotoxicity and ototoxicity.
- **Tetracyclines** - inhibit protein synthesis (30S subunit), bacteriostatic. Examples: Doxycycline, Tetracycline, Minocycline. Use: Acne, rickettsial infections, cholera, atypical pneumonia. Exam point: Contraindicated in children <8 years and pregnancy - tooth discolouration, bone growth suppression.

### B. Antitubercular Drugs (ATT)
- **Definition:** Drugs used to treat tuberculosis, given in combination to prevent resistance.
- **First-line drugs (RIPE):** Rifampicin - inhibits bacterial RNA polymerase. Isoniazid (INH) - inhibits mycolic acid synthesis. Pyrazinamide - bactericidal in acidic pH. Ethambutol - inhibits cell wall arabinogalactan synthesis (bacteriostatic).
- **DOTS:** Directly Observed Treatment, Short-course - patient takes drugs under direct observation; Intensive phase (2 months, 4 drugs) followed by Continuation phase (4 months, usually Rifampicin + Isoniazid).
- **Clinical use:** Pulmonary and extrapulmonary TB.
- **Exam point:** Rifampicin - orange-red discoloration of urine/secretions (harmless); Isoniazid - peripheral neuropathy (prevented by Vit B6); Ethambutol - optic neuritis; Pyrazinamide - hepatotoxicity/hyperuricemia.

## 11.10 Antifungal, Antiviral, Antimalarial and Anthelmintic Drugs

### A. Antifungal Drugs
- **Classification:** Polyenes (Amphotericin B, Nystatin) - bind ergosterol in fungal membrane. Azoles (Fluconazole, Itraconazole, Ketoconazole, Clotrimazole) - inhibit ergosterol synthesis. Allylamines (Terbinafine) - inhibit ergosterol synthesis earlier step. Echinocandins (Caspofungin) - inhibit fungal cell wall synthesis.
- **Clinical use:** Candidiasis, dermatophytosis (ringworm), systemic fungal infections.
- **Exam point:** Amphotericin B is highly nephrotoxic ("Ampho-terrible") - used for severe systemic mycoses.

### B. Antiviral Drugs
- **Classification:** Anti-herpes (Acyclovir, Valacyclovir) - inhibit viral DNA polymerase. Anti-HIV/ART (Zidovudine, Lamivudine, Efavirenz, Ritonavir) - inhibit reverse transcriptase/protease/integrase. Anti-influenza (Oseltamivir) - inhibit neuraminidase. Anti-hepatitis (Tenofovir, Entecavir, Sofosbuvir).
- **Clinical use:** Herpes, HIV/AIDS, influenza, viral hepatitis.
- **Exam point:** ART always given as combination therapy (HAART) to prevent resistance.

### C. Antimalarial Drugs
- **Classification:** Blood schizonticides (Chloroquine, Artesunate, Quinine) - kill parasite in RBCs. Tissue schizonticides (Primaquine) - act on liver stage to prevent relapse. ACT (Artemether + Lumefantrine) - for resistant P. falciparum.
- **Clinical use:** Treatment and prophylaxis of malaria; Primaquine prevents P. vivax relapse.
- **Exam point:** Primaquine causes haemolysis in G6PD-deficient patients - test before giving; Chloroquine resistance common in P. falciparum, ACT preferred.

### D. Anthelmintic Drugs
- **Classification:** Benzimidazoles (Albendazole, Mebendazole) - inhibit microtubule formation. Pyrantel/Levamisole group (Pyrantel pamoate) - depolarizing neuromuscular blockade paralyzing worm. Anti-filarial/anti-tapeworm (Diethylcarbamazine for filariasis; Praziquantel for tapeworm/schistosomiasis).
- **Clinical use:** Roundworm, hookworm, pinworm, tapeworm, filariasis.
- **Exam point:** Albendazole is broad-spectrum, single-dose, drug of choice for most worm infestations (National Deworming Day drug).

## 11.11 Hormones and Related Drugs

### A. Thyroid Hormone (Replacement)
- **Example:** Levothyroxine (T4) - increases metabolic rate.
- **Clinical use:** Hypothyroidism, myxoedema, post-thyroidectomy replacement.
- **Exam point:** Taken empty stomach in morning; overdose causes thyrotoxicosis symptoms (palpitations, weight loss, osteoporosis).

### B. Thyroid Inhibitors (Antithyroid Drugs)
- **Classification:** Thioamides (Carbimazole, Methimazole, Propylthiouracil) - inhibit thyroid peroxidase. Iodides (high dose) - inhibit hormone release (Wolff-Chaikoff effect). Radioactive iodine (I-131) - destroys thyroid tissue.
- **Clinical use:** Hyperthyroidism/Graves' disease, thyroid storm, pre-thyroidectomy preparation.
- **Exam point:** Propylthiouracil preferred in pregnancy (1st trimester); Carbimazole can cause agranulocytosis.

### C. Insulin
- **Classification (by duration):** Rapid-acting (Lispro, Aspart); Short-acting (Regular/soluble insulin); Intermediate-acting (NPH); Long-acting (Glargine, Detemir).
- **Mechanism:** Acts on insulin receptors to promote glucose uptake and glycogen synthesis.
- **Clinical use:** Type 1 DM (mandatory), Type 2 DM (when oral drugs fail), DKA, gestational diabetes.
- **Exam point:** Main side effect = hypoglycaemia; given subcutaneously (regular insulin can be IV in emergencies).

### D. Oral Antidiabetic Drugs
- **Classification:** Sulfonylureas (Glibenclamide, Glimepiride, Gliclazide) - stimulate insulin release. Biguanides (Metformin) - decrease hepatic glucose production, increase insulin sensitivity. DPP-4 inhibitors (Sitagliptin) - increase insulin secretion. SGLT2 inhibitors (Empagliflozin, Dapagliflozin) - block renal glucose reabsorption.
- **Clinical use:** Type 2 Diabetes Mellitus.
- **Exam point:** Metformin is first-line (no hypoglycaemia alone); Sulfonylureas can cause hypoglycaemia; Metformin avoided in renal failure (lactic acidosis risk).

### E. Hormonal Contraceptives
- **Classification:** Combined oral contraceptive pills (COCs) - estrogen+progesterone inhibit ovulation. Progesterone-only pills - thicken cervical mucus. Emergency contraceptive pill (Levonorgestrel). Injectables/Implants (DMPA, Implanon).
- **Clinical use:** Contraception, menstrual cycle regulation, dysfunctional uterine bleeding.
- **Exam point:** COCs contraindicated in smokers >35 yrs and history of thromboembolism.

### F. Uterine Stimulants (Oxytocics)
- **Classification:** Oxytocin - stimulates uterine contraction via oxytocin receptors. Ergometrine - sustained strong contraction. Prostaglandins (Misoprostol, Dinoprostone) - cervical ripening and contraction.
- **Clinical use:** Induction/augmentation of labour, control of postpartum haemorrhage (PPH).
- **Exam point:** Oxytocin for induction of labour; Ergometrine for PPH but contraindicated in hypertension/pre-eclampsia.

### G. Uterine Relaxants (Tocolytics)
- **Classification:** Beta-2 agonists (Isoxsuprine, Ritodrine). Calcium channel blockers (Nifedipine). Magnesium sulphate.
- **Clinical use:** Preterm labour (delay delivery, allow fetal lung maturation with steroids).
- **Exam point:** Magnesium sulphate also used in eclampsia for seizure prevention (dual use).

## 11.12 Miscellaneous Drugs

### A. Antiseptics and Disinfectants
- **Antiseptics** - applied to living tissue to prevent/inhibit microbial growth (Povidone-iodine, Chlorhexidine, Hydrogen peroxide, Alcohol 70%).
- **Disinfectants** - applied to non-living surfaces/instruments (Phenol, Formaldehyde, Sodium hypochlorite, Glutaraldehyde).
- **Exam point:** Same chemical can act as both depending on concentration (e.g., phenol).

### B. Vaccines
- **Classification:** Live attenuated (BCG, MMR, OPV, Varicella) - strong long-lasting immunity. Killed/Inactivated (IPV, Rabies, Hepatitis A) - needs boosters. Toxoid (Tetanus toxoid, Diphtheria toxoid). Subunit/conjugate (Hepatitis B, Pneumococcal conjugate).
- **Clinical use:** Prevention of infectious diseases (Universal Immunization Programme).
- **Exam point:** Live vaccines contraindicated in pregnancy and immunocompromised patients.

### C. Vitamins
- **Fat-soluble (A, D, E, K):** stored in body. Vit A deficiency - Night blindness/Xerophthalmia. Vit D deficiency - Rickets/Osteomalacia. Vit K deficiency - Bleeding disorders.
- **Water-soluble (B-complex, C):** not stored, need regular intake. B1 deficiency - Beriberi. B3 deficiency - Pellagra. B12/Folate deficiency - Megaloblastic anaemia. Vit C deficiency - Scurvy.
- **Exam point:** Fat-soluble vitamins can cause toxicity (Vit A & D); water-soluble rarely toxic (excreted in urine).

### D. Water Imbalance and IV Fluids
- **Classification:** Crystalloids (Normal saline, Ringer's Lactate, Dextrose 5%, Dextrose-saline) - small molecules crossing capillary membrane easily. Colloids (Human albumin, Dextran, Hydroxyethyl starch, Blood/plasma) - large molecules, stay in vessels, expand plasma volume.
- **Clinical use:** Crystalloids - dehydration, maintenance fluid therapy; Colloids - hypovolemic shock, severe blood/plasma loss.
- **Exam point:** Normal saline used in shock/dehydration; Ringer's Lactate avoided in liver failure and hyperkalemia; Dextrose provides calories/water, not electrolytes.

import re
from docx import Document
from docx.shared import Pt, RGBColor
from docx.enum.text import WD_ALIGN_PARAGRAPH

doc = Document()
style = doc.styles["Normal"]
style.font.name = "Calibri"
style.font.size = Pt(11)

title = doc.add_heading("BAMS Pharmacology Revision Notes", level=0)
sub = doc.add_paragraph("Principles of General Pharmacology (11 - 11.12) | NCISM Dravyaguna Vigyan Syllabus")
sub.alignment = WD_ALIGN_PARAGRAPH.CENTER
for run in sub.runs:
    run.italic = True
    run.font.size = Pt(12)
doc.add_page_break()

def add_bold_line(paragraph, text):
    """Parse **bold** markers within a line and add runs accordingly."""
    parts = re.split(r'(\*\*.*?\*\*)', text)
    for part in parts:
        if part.startswith('**') and part.endswith('**'):
            r = paragraph.add_run(part[2:-2])
            r.bold = True
        else:
            r = paragraph.add_run(part)

with open("/tmp/workspace/bams-pharmacology/content.md", "r") as f:
    lines = f.read().split("\n")

for line in lines:
    line = line.rstrip()
    if not line.strip():
        continue
    if line.startswith("# "):
        doc.add_heading(line[2:].strip(), level=1)
    elif line.startswith("## "):
        doc.add_heading(line[3:].strip(), level=2)
    elif line.startswith("### "):
        doc.add_heading(line[4:].strip(), level=3)
    elif line.startswith("- "):
        p = doc.add_paragraph(style="List Bullet")
        add_bold_line(p, line[2:].strip())
    else:
        p = doc.add_paragraph()
        add_bold_line(p, line.strip())

doc.save("/tmp/workspace/bams-pharmacology/output/BAMS_Pharmacology_11_to_11.12.docx")
print("Saved.")

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/bams-pharmacology/build_docx.py'