PHARMACOLOGY REVIEW

What is Pharmacology ? Pharmacology Pharmacokinetics Pharmacodynamics What the body does to drug What the drug does to body Pharmacotherapeutics Pharmacocognosy The study of the use of drugs Identifying crude materials as drugs Toxicology

What does the rate and efficacy of absorption depend on? Route of administration- the intravenous route is most effective. Blood flow- highly vascularized organs such as the small intestine have the greatest absorbing ability Surface area available- absorption of a drug is directly proportional to the surface area available

Solubility of a drug- the ratio of hydrophilic to lipophilic properties that a drug has will determine whether the drug can permeate cell membranes Drugs-drugs interaction- when given in combination, drugs can either enhance or inhibit one another’s absorption. pH- a drug’s acidity or alkalinity affects its charge which affects absorption

The four "must know" Pharm equations 1. Volume of Distribution 2. Clearance 3. Loading Dose 4. Maintenance Dose

INTRODUCTION TO AUTONOMIC NERVOUS SYSTEM (ANS) PHARMACOLOGY Human nervous system is divided into two main branches Central nervous system and Peripheral nervous system. The Peripheral nervous is further divided into 1. Somatic nervous system 2. Autonomic nervous system(ANS)

Why is this system important? The ANS regulates functions that are not under conscious control, such as blood pressure, heart rate and intestinal motility. Subdivisions of ANS 1. sympathetic nervous system 2. parasympathetic nervous system

What are the functions of the sympathetic nervous system The sympathetic nervous system is normally active, even at rest; however, it assumes a dominant role when the body becomes stressed in some way. For example, if you sense danger, your heart rate increases, blood pressure rises, eyes dilate, blood sugar rises, bronchioles expand and blood flows shifts from skin to skeletal muscles

The sympathetic nervous system prepares you for FLIGHT OR FIGHT situations The SNS work on ADRENERGIC RECEPTORS- alpha 1, alpha2, beta 1 receptors and beta 2 and dopamine receptors

What are the actions of the parasympathetic system? The PNS is predominant under tranquil conditions. It slows heart rate, lower blood pressure, increases intestinal activity, constricts the pupils and empties the urinary bladder. The parasympathetic nervous system is also know as the REST and DIGEST system The PNS acts on cholinergic receptors- muscarinic and nicotinic

WHAT ARE CHOLINERGIC AGONIST Cholinergic agonists are drugs that mimic or potentiate the actions of acethycholine

WHAT ARE THE TWO MAJOR FAMILIES OF CHOLINERGIC RECEPTORS 1. Muscarinic- this receptor family earned its name because it was first identified using muscarine, an alkaloid found in certain poisonous mushroom. 2. Nicotine

WHAT TYPES OF CHOLINERGIC AGONISTS ARE AVAILABLE FOR CLINICAL USE? Cholinergic agonists can be divided into two major groups: 1. Direct-acting agonists chemically bind with and activate muscarinic and nicotinic receptors in the body. 2. Indirect-acting agonists inhibit the enzyme acethycholinesterase and therefore increase the concentration of acethylcholine within the synapse

THERAPEUTIC USES Bethanechol increases intestinal motility, especially after surgery. Because this drug also stimulates the detrusor muscle of the bladder, it is also used to treat urinary retention. BBB- Bethanechol stimulates the Bladder and Bowel.

Carbachol This drug is rarely used in the clinics, but it can be used for GLAUCOMA and to stimulate miosis during ophthalmic surgery

Clinical use Pilocarpine is good miosis and opening the trabecular meshwork around the canal of schlemm. Therefore is used treatment of glaucoma Adverse effects? Pilocarpine is able to enter the brain and causes CNS disturbances such as hallucinations and convulsions, along with generalized cholinergic stimulation

Methacholine Methacholine used for diagnostic purposes. testing for bronchial hyper reactivity and asthma

Organophosphate poisoning Reactivation of acetylcholine esterase Pralidoxime (PAM) (Pyridine – 2 aldoxime chloride)

What are cholinergic antagonists? Drugs that bind to cholinergic receptors ( muscarinic and/or nicotinic), but do not trigger the usual intracellular response.

Name 3 subclasses of cholinergic antagonists. 1. Muscarinic blockers 2. Neuromuscular blocking agents- inhibit the efferent impulses to skeletal muscle via the nicotinic muscle receptor (Nm) 3. Ganglionic blockers- inhibit the nicotinic neuronal receptor (Nn) of both parasympathetic and sympathetic ganglia

Muscarinic antagonists Give six examples of muscarinic blockers 1. atropine 2. scopolamine 3. homatopine 4. cyclopentolate 5. tropicamide 6. pirenzepine

ATROPINE – high affinity for muscarinic receptors. acts both centrally and peripherally It causes reversible, nonselective blockade of muscarinic receptors. Mydriasis, cycloplegia. Eneuresis in children Low doses- bradycardia. High doses—tachycardia Dilates cutaneous vasculature

Lung Broncho -dilation:Ipratropium Mainly used as inhalation in treating asthma and COPD. Atropine prior to surgery will decrease the respiratory secretions

GI tract Salivary secretions decrease Can cause dry mouth and difficulty in swallowing Only Pirenzepine has some potency to decrease hyperacidity..