DIMS Lectures Pharmacology PDF
Introduction
Pharmacology is the science of drugs and their effects on the human body. It encompasses the study of drug interactions, mechanisms of action, therapeutic uses, and side effects.
1. Autonomic Nervous System (ANS) Pharmacology
The autonomic nervous system (ANS) regulates involuntary bodily functions, such as heart rate, digestion, and respiratory rate. It is divided into two main branches: the sympathetic and parasympathetic nervous systems. Drugs that act on the ANS can either stimulate or inhibit these systems, leading to various physiological effects.
Cholinergic Agonists and Antagonists
Cholinergic agonists mimic the action of acetylcholine (ACh), a neurotransmitter in the parasympathetic nervous system. Examples include pilocarpine (used for glaucoma) and neostigmine (used for myasthenia gravis).
Cholinergic antagonists, also known as antimuscarinics, block the action of ACh. Atropine is a classic example, used to treat bradycardia and as a pre-anesthetic medication.
Adrenergic Agonists and Blockers
Adrenergic agonists stimulate the sympathetic nervous system by mimicking norepinephrine and epinephrine. Examples include epinephrine (used for anaphylaxis) and albuterol (used for asthma).
Adrenergic blockers inhibit the sympathetic nervous system. Beta-blockers like propranolol are used to treat hypertension and arrhythmias, while alpha-blockers like prazosin are used for benign prostatic hyperplasia (BPH).
2. Central Nervous System (CNS) Pharmacology
The CNS includes the brain and spinal cord, and drugs acting on the CNS can have profound effects on mood, cognition, and behavior.
Sedatives and Hypnotics
Benzodiazepines (e.g., diazepam) are commonly used for anxiety and insomnia. They enhance the effect of GABA, an inhibitory neurotransmitter.
Barbiturates (e.g., phenobarbital) are older sedatives with a higher risk of dependence and overdose.
Antiepileptic Drugs
Phenytoin and carbamazepine are used to control seizures by stabilizing neuronal membranes and reducing abnormal electrical activity in the brain.
Valproic acid is another antiepileptic drug, but it carries risks of hepatotoxicity and teratogenicity.
Antipsychotics and Antidepressants
Antipsychotics like haloperidol and clozapine are used to treat schizophrenia and other psychotic disorders by blocking dopamine receptors.
Antidepressants such as fluoxetine (an SSRI) and amitriptyline (a tricyclic antidepressant) are used to treat depression by increasing levels of serotonin and norepinephrine in the brain.
3. Respiratory System Pharmacology
Drugs targeting the respiratory system are essential for managing conditions like asthma, chronic obstructive pulmonary disease (COPD), and allergic rhinitis.
Bronchodilators
Beta-2 agonists like salbutamol and salmeterol relax bronchial smooth muscles, making them effective for asthma and COPD.
Anticholinergics like ipratropium are also used to dilate airways, particularly in COPD.
Anti-inflammatory Drugs
Corticosteroids (e.g., prednisone) reduce inflammation in the airways and are used for long-term asthma control.
Leukotriene modifiers like montelukast block inflammatory mediators and are used for allergic rhinitis and asthma.
4. Gastrointestinal (GI) Pharmacology
The GI system is regulated by a complex interplay of nerves, hormones, and muscles. Drugs targeting the GI tract are used to treat conditions like peptic ulcers, gastroesophageal reflux disease (GERD), and irritable bowel syndrome (IBS).
Proton Pump Inhibitors (PPIs)
Omeprazole and lansoprazole reduce stomach acid production by inhibiting the proton pump in gastric parietal cells. They are used for peptic ulcers and GERD.
Antiemetics
Metoclopramide and ondansetron are used to prevent nausea and vomiting by blocking dopamine and serotonin receptors, respectively.
Laxatives
Bulk-forming laxatives like psyllium and stimulant laxatives like bisacodyl are used to treat constipation by increasing stool bulk or stimulating bowel movements.
5. Cardiovascular Pharmacology
Cardiovascular drugs are used to treat conditions like hypertension, heart failure, and arrhythmias.
Antihypertensives
ACE inhibitors like lisinopril and ARBs like losartan lower blood pressure by relaxing blood vessels.
Calcium channel blockers like amlodipine are also used to treat hypertension and angina.
Antiarrhythmics
Beta-blockers like metoprolol and sodium channel blockers like lidocaine are used to treat abnormal heart rhythms.
Anticoagulants
Heparin and warfarin are used to prevent blood clots in conditions like deep vein thrombosis (DVT) and atrial fibrillation.
6. Endocrine Pharmacology
Endocrine drugs target hormone-related conditions like diabetes, thyroid disorders, and adrenal insufficiency.
Antidiabetic Drugs
Insulin is essential for managing type 1 diabetes, while metformin is a first-line treatment for type 2 diabetes.
Sulfonylureas like glibenclamide stimulate insulin secretion and are used for type 2 diabetes.
Thyroid Hormones
Levothyroxine is used to treat hypothyroidism by replacing deficient thyroid hormones.
7. Antimicrobial Pharmacology
Antimicrobial drugs are used to treat infections caused by bacteria, viruses, fungi, and parasites.
Antibiotics
Penicillins (e.g., amoxicillin) and cephalosporins (e.g., ceftriaxone) are used to treat bacterial infections.
Tetracyclines like doxycycline are used for infections like Lyme disease and acne.
Antifungals
Amphotericin B and fluconazole are used to treat systemic fungal infections like candidiasis and cryptococcosis.
Antivirals
Acyclovir is used for herpes infections, while oseltamivir is used for influenza.
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