[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › General principles # General principles 95 pages - [**Acid-peptic disease: physiology and treatment strategy** How the stomach makes acid and protects itself, and how reflux, ulcers, H. pylori infection and indigestion…](https://durgical.com/en/pharmacology/topics/acid-peptic-disease-physiology-and-treatment-strategy/) - [**Adrenal cortex: steroid synthesis and endocrine disorders** How the adrenal glands make cortisol, aldosterone and androgens, and how adrenal insufficiency, CAH and…](https://durgical.com/en/pharmacology/topics/adrenal-cortex-steroid-synthesis-and-endocrine-disorders/) - [**Adrenergic transmission** How the body makes, releases, recycles and breaks down noradrenaline and adrenaline, and how drugs act on…](https://durgical.com/en/pharmacology/topics/adrenergic-transmission/) - [**Adverse drug reactions** Harm caused by a medicine used normally: why it happens, the main types, and how a suspected reaction is…](https://durgical.com/en/pharmacology/topics/adverse-drug-reactions/) - [**Agonists and antagonists** Drugs that switch a receptor on, switch it partly on, or block it, and the different ways one drug can…](https://durgical.com/en/pharmacology/topics/agonists-and-antagonists/) - [**Allergen immunotherapy** Regular, controlled doses of an allergen, by injection or under the tongue, retrain the immune system so…](https://durgical.com/en/pharmacology/topics/allergen-immunotherapy/) - [**Antifungal therapy: fungal biology and drug targets** Fungi are cells much like ours, so antifungals aim at the few parts that differ: the membrane sterol…](https://durgical.com/en/pharmacology/topics/antifungal-therapy-fungal-biology-and-drug-targets/) - [**Antimicrobial resistance** How microbes escape antimicrobials, how resistance spreads between them and between countries, and how…](https://durgical.com/en/pharmacology/topics/antimicrobial-resistance/) - [**Antiviral therapy: the viral replication cycle and drug targets** Viruses use our own cells to copy themselves. Antivirals block the few steps that belong only to the virus.](https://durgical.com/en/pharmacology/topics/antiviral-therapy-the-viral-replication-cycle-and-drug-targets/) - [**Asthma and COPD: mechanisms, inhalers and step-wise treatment** Why airways narrow in asthma and COPD, how inhaled medicines reach the lungs, and how treatment is stepped…](https://durgical.com/en/pharmacology/topics/asthma-and-copd-mechanisms-inhalers-and-step-wise-treatment/) - [**Autonomic nervous system: overview** The automatic wiring that controls heart rate, blood pressure, airways, gut, bladder, pupils and glands, and…](https://durgical.com/en/pharmacology/topics/autonomic-nervous-system-overview/) - [**Autonomic receptor subtypes** Where each adrenergic, muscarinic and nicotinic receptor is found, what it does and which drugs target it…](https://durgical.com/en/pharmacology/topics/autonomic-receptor-subtypes/) - [**Beta-lactam allergy: penicillin labels, cross-reactivity and delabelling** Many people are labelled allergic to penicillin, but few truly are. Checking the label opens the door to…](https://durgical.com/en/pharmacology/topics/beta-lactam-allergy-penicillin-labels-cross-reactivity-and-delabelling/) - [**Biologics and nucleic acid medicines** Medicines made from proteins, cells or genetic material: antibodies, hormones, antisense and siRNA drugs…](https://durgical.com/en/pharmacology/topics/biologics-and-nucleic-acid-medicines/) - [**Calcium, phosphate and bone: physiology and disorders** How the body keeps calcium and phosphate in balance, how bone is constantly rebuilt, and what goes wrong in…](https://durgical.com/en/pharmacology/topics/calcium-phosphate-and-bone-physiology-and-disorders/) - [**Cardiac electrophysiology and how arrhythmias arise** How each heartbeat is an electrical wave, how that wave goes wrong, and why drugs that fix rhythm can also…](https://durgical.com/en/pharmacology/topics/cardiac-electrophysiology-and-how-arrhythmias-arise/) - [**Cell signalling pathways: energy, growth, survival and death** How cells sense energy and nutrients, decide to grow, recycle or die, and how drugs such as mTOR and BCL-2…](https://durgical.com/en/pharmacology/topics/cell-signalling-pathways-energy-growth-survival-and-death/) - [**Cephalosporin generations** How cephalosporins are grouped into generations 1 to 5, what each covers, and the gaps they all share…](https://durgical.com/en/pharmacology/topics/cephalosporin-generations/) - [**Chemical carcinogens, chemoprevention and aflatoxin** How chemicals cause cancer, how agencies rank carcinogens, and how drugs and public health measures can…](https://durgical.com/en/pharmacology/topics/chemical-carcinogens-chemoprevention-and-aflatoxin/) - [**Cholinergic transmission** How nerve cells make, release and break down acetylcholine, the two receptor families it acts on, and the…](https://durgical.com/en/pharmacology/topics/cholinergic-transmission/) - [**Depression and anxiety: biology and drug treatment** What is thought to go wrong in the brain in depression and anxiety, and how antidepressants and other…](https://durgical.com/en/pharmacology/topics/depression-and-anxiety-biology-and-drug-treatment/) - [**Dermatological pharmacology: skin, vehicles and light** How drugs get through the skin, why the cream or ointment matters, and how light, sunscreens, itch…](https://durgical.com/en/pharmacology/topics/dermatological-pharmacology-skin-vehicles-and-light/) - [**Diabetes mellitus: pathophysiology and management** How the body controls blood sugar, why it fails in the different types of diabetes, how diabetes is…](https://durgical.com/en/pharmacology/topics/diabetes-mellitus-pathophysiology-and-management/) - [**Dietary supplements and herbal products** How supplements are regulated, why «natural» does not mean safe, and the interactions and hidden ingredients…](https://durgical.com/en/pharmacology/topics/dietary-supplements-and-herbal-products/) - [**Dose–response and therapeutic index** How effect grows with dose, the difference between a more potent and a more effective drug, and how close…](https://durgical.com/en/pharmacology/topics/dose-response-and-therapeutic-index/) - [**Dosing regimens and therapeutic drug monitoring** Why some drugs start with a larger first dose, how blood levels guide treatment, and why kidney or liver…](https://durgical.com/en/pharmacology/topics/dosing-regimens-and-therapeutic-drug-monitoring/) - [**Drug discovery and development** The long path from an idea about a disease target to a medicine on the pharmacy shelf: laboratory work…](https://durgical.com/en/pharmacology/topics/drug-discovery-and-development/) - [**Drug elimination, clearance and half-life** How the body removes a drug, why some drugs last hours and others weeks, and why levels build up when dosing…](https://durgical.com/en/pharmacology/topics/drug-elimination-clearance-and-half-life/) - [**Drug interactions** How one medicine, food, supplement or illness can change the effect of another medicine, and how to spot the…](https://durgical.com/en/pharmacology/topics/drug-interactions/) - [**Drug metabolism and cytochrome P450** How the liver and gut chemically change drugs, why some drugs speed up or slow down others, and how prodrugs…](https://durgical.com/en/pharmacology/topics/drug-metabolism-and-cytochrome-p450/) - [**Drug transporters** Membrane proteins that pump drugs into or out of cells in the gut, liver, kidney and brain, and a frequent…](https://durgical.com/en/pharmacology/topics/drug-transporters/) - [**Eicosanoids: prostaglandins, thromboxanes and leukotrienes as drug targets** The lipid messengers made from arachidonic acid, and the anti-inflammatories, antiplatelet drugs, asthma…](https://durgical.com/en/pharmacology/topics/eicosanoids-prostaglandins-thromboxanes-and-leukotrienes-as-drug-targets/) - [**Environmental and occupational toxicology** How air pollution, solvents, pesticides and other chemicals at home and at work harm health, and how…](https://durgical.com/en/pharmacology/topics/environmental-and-occupational-toxicology/) - [**Epilepsy: seizure types and drug treatment** How seizures are classified, why they happen, how antiseizure medicines are matched to seizure type, and how…](https://durgical.com/en/pharmacology/topics/epilepsy-seizure-types-and-drug-treatment/) - [**Ethanol and toxic alcohols** How alcohol acts and harms, how withdrawal is recognised and treated, and why methanol and ethylene glycol…](https://durgical.com/en/pharmacology/topics/ethanol-and-toxic-alcohols/) - [**Gender-affirming hormone therapy** How sex hormones and hormone blockers are used, under specialist care, to help transgender and…](https://durgical.com/en/pharmacology/topics/gender-affirming-hormone-therapy/) - [**General anaesthesia: principles, effects and special patients** What general anaesthesia does to the brain and body, why patients get cold or sick afterwards, and how care…](https://durgical.com/en/pharmacology/topics/general-anaesthesia-principles-effects-and-special-patients/) - [**Generics, biosimilars and bioequivalence** Why a generic medicine works like the original, how biosimilars differ from generics, and how patents and…](https://durgical.com/en/pharmacology/topics/generics-biosimilars-and-bioequivalence/) - [**Geriatric pharmacology** How ageing changes the response to medicines, why many medicines at once is risky, and how medicines are…](https://durgical.com/en/pharmacology/topics/geriatric-pharmacology/) - [**GI motility, water flux and vomiting** How the gut moves food along and handles water, what goes wrong in motility disorders like gastroparesis…](https://durgical.com/en/pharmacology/topics/gi-motility-water-flux-and-vomiting/) - [**Gut microbiome and drug response** The bacteria in the gut can switch drugs on, switch them off or make them more toxic, which helps explain…](https://durgical.com/en/pharmacology/topics/gut-microbiome-and-drug-response/) - [**Haematopoiesis, iron and the megaloblastic anaemias** How bone marrow makes blood cells, what growth factors steer it, and how lack of iron, vitamin B12 or folate…](https://durgical.com/en/pharmacology/topics/haematopoiesis-iron-and-the-megaloblastic-anaemias/) - [**Haemostasis: platelets, clotting and clot breakdown** How the body plugs a cut blood vessel, keeps clots from spreading and later dissolves them, and where…](https://durgical.com/en/pharmacology/topics/haemostasis-platelets-clotting-and-clot-breakdown/) - [**Heart failure: mechanisms and the combined drug regimen** Why a weak heart gets worse over time, and how a set of drugs taken together slows that down and helps…](https://durgical.com/en/pharmacology/topics/heart-failure-mechanisms-and-the-combined-drug-regimen/) - [**Heavy metal poisoning** Lead, mercury, arsenic, cadmium and iron: where exposure comes from, what each metal damages and when…](https://durgical.com/en/pharmacology/topics/heavy-metal-poisoning/) - [**Histamine and bradykinin** Two mediators of swelling: histamine drives allergy and acid secretion; bradykinin drives ACE-inhibitor and…](https://durgical.com/en/pharmacology/topics/histamine-and-bradykinin/) - [**HIV: life cycle and principles of antiretroviral therapy** How HIV copies itself inside immune cells, and why treatment uses several drugs together, taken every day…](https://durgical.com/en/pharmacology/topics/hiv-life-cycle-and-principles-of-antiretroviral-therapy/) - [**Hormonal therapy of cancer: breast, prostate, neuroendocrine and thyroid tumours** Some cancers grow on hormones. Removing the hormone or blocking its receptor slows them, often for years.](https://durgical.com/en/pharmacology/topics/hormonal-therapy-of-cancer-breast-prostate-neuroendocrine-and-thyroid-tumours/) - [**Immunity and inflammation: basics for pharmacology** The innate and adaptive immune systems and the mediators of inflammation, as the background needed to…](https://durgical.com/en/pharmacology/topics/immunity-and-inflammation-basics-for-pharmacology/) - [**Inflammatory bowel disease: pathogenesis and treatment** What Crohn's disease and ulcerative colitis are, why they happen, and how medicines, nutrition and…](https://durgical.com/en/pharmacology/topics/inflammatory-bowel-disease-pathogenesis-and-treatment/) - [**Insomnia: types and management** Why people sleep badly, why behavioural therapy comes first, and when and how sleep medicines are used.](https://durgical.com/en/pharmacology/topics/insomnia-types-and-management/) - [**Ischaemic heart disease: oxygen balance, stable disease and acute syndromes** Why narrowed heart arteries cause chest pain or a heart attack, and how drugs, stents and clot treatment fit…](https://durgical.com/en/pharmacology/topics/ischaemic-heart-disease-oxygen-balance-stable-disease-and-acute-syndromes/) - [**Lipoproteins, cardiovascular risk and lipid-lowering strategy** How fats travel in the blood, why LDL and lipoprotein(a) build up in arteries, and how treatment is matched…](https://durgical.com/en/pharmacology/topics/lipoproteins-cardiovascular-risk-and-lipid-lowering-strategy/) - [**Managing the poisoned patient** The general approach to a poisoning: support breathing and circulation first, then decontaminate, speed…](https://durgical.com/en/pharmacology/topics/managing-the-poisoned-patient/) - [**Medication adherence** Why many people do not take medicines as agreed, what that costs, and which practical changes help.](https://durgical.com/en/pharmacology/topics/medication-adherence/) - [**Neurobiology of addiction** How drugs hijack the brain's reward system, the difference between tolerance, dependence and addiction, and…](https://durgical.com/en/pharmacology/topics/neurobiology-of-addiction/) - [**Neurodegenerative diseases: shared biology, Parkinson and Alzheimer** Why some brain cells slowly die in Parkinson and Alzheimer disease, which proteins build up, and what…](https://durgical.com/en/pharmacology/topics/neurodegenerative-diseases-shared-biology-parkinson-and-alzheimer/) - [**Neuromuscular junction and autonomic ganglia** How a nerve makes a skeletal muscle contract, how neuromuscular blockers used in anaesthesia stop it, and…](https://durgical.com/en/pharmacology/topics/neuromuscular-junction-and-autonomic-ganglia/) - [**Neurotransmission in the central nervous system** How brain cells talk through chemical messengers, and how sedatives, antidepressants, antipsychotics and…](https://durgical.com/en/pharmacology/topics/neurotransmission-in-the-central-nervous-system/) - [**Nitric oxide pharmacology** How the gas nitric oxide relaxes blood vessels through cGMP, and the nitrates, PDE5 inhibitors, sGC…](https://durgical.com/en/pharmacology/topics/nitric-oxide-pharmacology/) - [**Obstetric pharmacotherapy: pre-eclampsia and preterm labour** How medicines are used to control blood pressure and prevent seizures in pre-eclampsia, and to delay preterm…](https://durgical.com/en/pharmacology/topics/obstetric-pharmacotherapy-pre-eclampsia-and-preterm-labour/) - [**Ocular pharmacology: getting drugs into the eye** How eye drops, injections and implants reach the eye, why some drops act on the whole body, and how pills…](https://durgical.com/en/pharmacology/topics/ocular-pharmacology-getting-drugs-into-the-eye/) - [**Opioid pharmacology: receptors, tolerance and opioid use disorder** How the body's own opioids and opioid drugs work, why the effect fades with time, and how opioid use…](https://durgical.com/en/pharmacology/topics/opioid-pharmacology-receptors-tolerance-and-opioid-use-disorder/) - [**Over-the-counter medicines** What makes a medicine safe enough to sell without a prescription, and the hidden risks of self-medication.](https://durgical.com/en/pharmacology/topics/over-the-counter-medicines/) - [**Overdose of beta-blockers, calcium channel blockers and antipsychotics** Why heart pills and antipsychotics are dangerous in overdose, what the poisoning looks like and which…](https://durgical.com/en/pharmacology/topics/overdose-of-beta-blockers-calcium-channel-blockers-and-antipsychotics/) - [**Paediatric and perinatal pharmacology** Why newborns and children handle medicines differently from adults, why doses are based on weight, and which…](https://durgical.com/en/pharmacology/topics/paediatric-and-perinatal-pharmacology/) - [**Penicillin groups** Penicillins grouped by spectrum: natural, antistaphylococcal, aminopenicillins and antipseudomonal, and why…](https://durgical.com/en/pharmacology/topics/penicillin-groups/) - [**Persistent environmental pollutants and endocrine disruptors** Chemicals such as PCBs, dioxins, PFAS, BPA and phthalates that stay in the body and the environment and can…](https://durgical.com/en/pharmacology/topics/persistent-environmental-pollutants-and-endocrine-disruptors/) - [**Pesticide toxicology: organochlorines, botanicals and herbicides** How insect and weed killers such as DDT, pyrethrins, glyphosate and paraquat harm people, and why pesticide…](https://durgical.com/en/pharmacology/topics/pesticide-toxicology-organochlorines-botanicals-and-herbicides/) - [**Pharmacodynamics: receptors and signalling** What a drug does to the body: the molecular targets drugs bind, the signals they set off, and why responses…](https://durgical.com/en/pharmacology/topics/pharmacodynamics-receptors-and-signalling/) - [**Pharmacogenetics** How inherited differences in genes change the way a person handles a drug or reacts to it, and when a…](https://durgical.com/en/pharmacology/topics/pharmacogenetics/) - [**Pharmacokinetics: absorption and distribution** What the body does to a drug: how it gets in, how much reaches the blood and where it goes before it is…](https://durgical.com/en/pharmacology/topics/pharmacokinetics-absorption-and-distribution/) - [**Pharmacovigilance and post-marketing safety** How adverse effects are detected, reported and acted on after a medicine is approved, and how health workers…](https://durgical.com/en/pharmacology/topics/pharmacovigilance-and-post-marketing-safety/) - [**Precision oncology: driver mutations, biomarker testing and liquid biopsy** Testing a tumour's genes can show which targeted drug may work. Tumours change over time, so testing may…](https://durgical.com/en/pharmacology/topics/precision-oncology-driver-mutations-biomarker-testing-and-liquid-biopsy/) - [**Prescribing in pregnancy and breastfeeding** How drugs cross the placenta and into milk, when the embryo is most vulnerable, and how risk is described on…](https://durgical.com/en/pharmacology/topics/prescribing-in-pregnancy-and-breastfeeding/) - [**Principles of antimicrobial therapy** How an antibiotic is chosen: likely microbe, site, patient and killing pattern, using the narrowest…](https://durgical.com/en/pharmacology/topics/principles-of-antimicrobial-therapy/) - [**Principles of cancer chemotherapy** How cytotoxic drugs exploit cell division, why they are given in combinations and cycles, and why they share…](https://durgical.com/en/pharmacology/topics/principles-of-cancer-chemotherapy/) - [**Principles of clinical toxicology** Why any substance can be a poison at the wrong dose, how poisons injure cells, and the difference between…](https://durgical.com/en/pharmacology/topics/principles-of-clinical-toxicology/) - [**Principles of immunopharmacology** Where immunosuppressants and biologics act, how to read their names, why they raise infection and cancer…](https://durgical.com/en/pharmacology/topics/principles-of-immunopharmacology/) - [**Principles of vaccines and immunisation** Active and passive immunity, the main vaccine types, the cold chain and how Colombia's Expanded Programme on…](https://durgical.com/en/pharmacology/topics/principles-of-vaccines-and-immunisation/) - [**Protozoal infections: amebiasis, giardiasis, trichomoniasis, toxoplasmosis and cryptosporidiosis** Single-celled parasites that cause diarrhoea, liver abscess, a sexually transmitted infection and dangerous…](https://durgical.com/en/pharmacology/topics/protozoal-infections-amebiasis-giardiasis-trichomoniasis-toxoplasmosis-and-crypt/) - [**Psychosis and mania: neurotransmitters and treatment** Why psychosis is linked to dopamine, serotonin and glutamate, and how antipsychotics and mood stabilisers…](https://durgical.com/en/pharmacology/topics/psychosis-and-mania-neurotransmitters-and-treatment/) - [**Rational prescribing** How to choose the right medicine for the right patient, write a clear and legal prescription in Colombia…](https://durgical.com/en/pharmacology/topics/rational-prescribing/) - [**Resistance to cancer drugs** Why tumours stop responding to chemotherapy and targeted drugs: efflux pumps, target mutations, bypass…](https://durgical.com/en/pharmacology/topics/resistance-to-cancer-drugs/) - [**Serotonin and dopamine pharmacology** Serotonin (5-HT) and dopamine receptor families, and the antidepressants, antiemetics, migraine…](https://durgical.com/en/pharmacology/topics/serotonin-and-dopamine-pharmacology/) - [**The blood–brain barrier** Why many drugs never reach the brain, how some are designed to get in and others to stay out, and what…](https://durgical.com/en/pharmacology/topics/the-blood-brain-barrier/) - [**The endocannabinoid system** The body's own cannabis-like signalling system: small fats made on demand that tune nerve signals, appetite…](https://durgical.com/en/pharmacology/topics/the-endocannabinoid-system/) - [**The hypothalamic–pituitary axis** How the hypothalamus and pituitary run the thyroid, adrenal, gonadal, growth and milk axes through feedback…](https://durgical.com/en/pharmacology/topics/the-hypothalamic-pituitary-axis/) - [**The nephron and how diuretics work** How the kidney filters blood and takes back salt and water segment by segment, and how each diuretic blocks…](https://durgical.com/en/pharmacology/topics/the-nephron-and-how-diuretics-work/) - [**Thyroid hormone: physiology, tests and hypothyroidism** How the thyroid makes its hormones, how they act on nearly every organ, how blood tests are read, and how an…](https://durgical.com/en/pharmacology/topics/thyroid-hormone-physiology-tests-and-hypothyroidism/) - [**Topical corticosteroids: potency, vehicles and safety** How skin steroids are ranked from mild to very potent, how the base changes their effect, and how to avoid…](https://durgical.com/en/pharmacology/topics/topical-corticosteroids-potency-vehicles-and-safety/) - [**Toxidromes** The five classic patterns of poisoning (cholinergic, anticholinergic, sympathomimetic, opioid, sedative) and…](https://durgical.com/en/pharmacology/topics/toxidromes/) - [**Treating high blood pressure: strategy and drug choice** How doctors bring blood pressure down: lifestyle first, then a few proven drug families, often two together…](https://durgical.com/en/pharmacology/topics/treating-high-blood-pressure-strategy-and-drug-choice/) - [**Vasoactive peptides** Angiotensin, natriuretic peptides, endothelin, vasopressin, substance P and CGRP: peptides that set vessel…](https://durgical.com/en/pharmacology/topics/vasoactive-peptides/) - [**Viral hepatitis B and C: virology and treatment principles** Hepatitis B can be controlled but rarely cured; hepatitis C can now be cured with tablets. This page…](https://durgical.com/en/pharmacology/topics/viral-hepatitis-b-and-c-virology-and-treatment-principles/) [← Pharmacology](https://durgical.com/en/pharmacology/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/topics/