Pharmacology

Receptor Mediated Drugs


Agonists

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Antagonists

Agonist-antagonists

Competitive agonists

Agonists – bind to receptor and cause response

Antagonists – bind to receptor but does not create response (blocks)

Agonist-antagonists – may create both (Nubain)

Competitive Agonists – some drugs bind to receptors, create an expected response but blocks other responses

Schedule I
High Abuse Potential
No Recognized Medical Use
Heroin/LSD/Mescaline
Schedule II
Written Prescription Required
High Abuse Potential
Codeine/Morphine/Meperidine
Amphetamines/Phenmetrazine
Schedule III
High Abuse Potential
Prescription Required
Opiates/Stimulants/Depressants/Anabolic Steroids
Schedule IV
Prescription Required
Low Abuse Potential
Opiates/Stimulants/Depressants
Schedule V
Dispensed as any non-opiate Prescription
Low Abuse Potential
Drug Absorption
Dependent on:
1.Solubility of drug
2.Concentration
3.Ph of drug
4.Site of absorption
5.Absorption area of site
6.Blood supply to area
7.Bioavailability
Distribution
Affected by:
1.Cardiovascular function
2.Regional blood flow
3.Drug storage reservoirs
4.Physiological barriers
Biotransformation
Name given to the metabolism of drugs
Has one of two effects on drugs:
1.transforms the drug into a more or less active metabolite
2.Makes the drug more water soluble to facilitate excretion
Assay
Test that determines the amount and purity of a drug
Bioequivalent
Relative therapeutic effectiveness of chemically equivalent drugs
First Pass Effect
Process by which enteral drugs are absorbed via the GI track and through the liver, partially or completely inactivating the drug.
Idiosyncrasy
Drug effect that is unique to an individual, different than seen or espected of the rest of the population
Cross Tolerance
Tolerance that develops after administration of a different drug. Example: tolerance for Morphine will implies tolerance for other drug of same category
Synergism
Two drugs having the same effect given together produce a response greater then the sum of the two (1+1=3)
Summation
Two drugs that bothe have the same effect given together have double the effect (1+1=2)
Theraputic Index

Ratio of a drug’s lethal dose for 50% of the population to its effective dose for 50% of the population.

TI = LD50/ED50

Biologocal Half-Life
Time the body takes to clear one half (1/2) of a drug
Analgesics

Drugs that relieve the sensation of pain

Analgesic – absence of sensation of pain

Anesthetic – absence of all sensations

Nervous System

Central Nervous System (CSN)

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Peripheral Nervous System

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;;;;;;;;;;;;;; ; ; ; ; ; ; ;; Autonomic;;; Somatic

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;;;;;;;;;;; Sympathetic;;;;;;;;;;; Parasympathetic

Opioids

Agonist – derived from opium, act by decreasing the sensory neuron’s ability to propagate pain impulses.

Antagonist – reverse the effects of opioids

Agonist-antagonist – decreases pain response without depressing respirations

Nonopioid analgesicsSalicylates like ASA, Nonsteroidal anti-inflamatory drugs (NSAIDS) like Ibuprofen and Paraaminophenol derivatives like Acetaminophen, affect the production of neurotransmitters.

Sympathetic Nervous System

Fight or Flight

Preganglionic nerves – Acetylcholine neurotranmitters – affect cholinergic synapses

Postganglionic nerves – Norepinephrine neurotransmitters – affect adrenergic synapses


Parasympathetic Nervous System

uses Acetylcholine as a neurotransmitter

affects cholinergic receptors

stimulate – parasympathomimetic

block – parasympatholytics

Cholinergic Drugs

Muscarinic and Nicotinic receptors

direct-acting – bind directly with the cholinergic receptors

result in SLUDGE

indirect-acting – affect acetylcholinesterase, the chemical responsible for destroying acetylcholine

 

SLUDGE

Salivation

Lacrimation

Urination

Defecation

Gastric motility

Emesis

Anticholinergics

Oppose parasympathetic responses

 

Muscarinic Cholinergic Antagonist

also called Anticholinergics

Competitively bind with muscarinic receptors without stimulating them.

Prevents acetylcholide from binding

ex: Atropine

Nicotininc Cholinergic Antagonists

block Nicotinic receptors

block receptors either at Ganglia or neuromuscular junction

Drugs used to affect the Parasympathetic Nervous System

Cholinergic

Anticholinergic

Ganglionit Blocking agents

Neuromuscular Blocking Agents

Ganglionic Stimuling Agents

Ganglionic Blocking Agents

Competitive agonist at the nicotinic recptors in the autonomic ganglia

Block acetylcholine

Neuromuscular Blocking Agents

produces state of paralysis without affecting consciousness.

 

Ganglionic Stimulating Agents

Stimulated by nicotine

 

 

Drugs used to affect the sympathetic Nervous System

Adrenergic Agonists

sympathomimetics

Adrenergic Antagonists

sympatholytics

Skeletal Muscle Relaxants

Adrenergic Receptors

Alpha11)– Vasoconstriction

Alpha22) – Presynapsic terminal inhibition

Beta11) – Increased HR, contractility, conductivity and automaticity

Beta22) – Bronchodilation + arteriole dilation

Beta33) –Lypolysis of adipose tissues

Dopaminergic – vasodilation in the kidneys

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