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PHARMACOLOGY. Dr Chris Bax London Metropolitan University Dept. Health & Human Sciences c.bax@londonmet.ac.uk. Learning Objectives:. Learning Objectives: Pharmacological principles and processes. Learning Objectives: Pharmacological principles and processes
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PHARMACOLOGY Dr Chris Bax London Metropolitan University Dept. Health & Human Sciences c.bax@londonmet.ac.uk
Learning Objectives: • Pharmacological principles and processes
Learning Objectives: • Pharmacological principles and processes • Drug bioavailability – how do we ensure that a drug is “available”? E.G: will it be absorbed from the gut? • Pharmacokinetics – what the body does to the drug. A D M E
Learning Objectives: • Pharmacological principles and processes • Drug bioavailability – how do we ensure that a drug is “available”? E.G: will it be absorbed from the gut? • Pharmacokinetics – what the body does to the drug. A D M E
Learning Objectives: • Pharmacological principles and processes • Drug bioavailability – how do we ensure that a drug is “available”? E.G: will it be absorbed from the gut? • Pharmacokinetics – what the body does to the drug: A D M E
Pharmacodynamics – what the drug does to the body (esp. at receptor level; drug receptor interactions) • Benefit:risk ratio – the therapeutic index. • Drug overdose and poisoning. • Drug dependence and abuse • An introduction to the pharmacology of the autonomic nervous system
Pharmacodynamics – what the drug does to the body (esp. at receptor level; drug receptor interactions) • the therapeutic index. • Drug overdose and poisoning. • Drug dependence and abuse • An introduction to the pharmacology of the autonomic nervous system
Pharmacodynamics – what the drug does to the body (esp. at receptor level; drug receptor interactions) • Benefit:risk ratio – the therapeutic index. • Drug overdose and poisoning. • Drug dependence and abuse • An introduction to the pharmacology of the autonomic nervous system
Pharmacodynamics – what the drug does to the body (esp. at receptor level; drug receptor interactions) • Benefit:risk ratio – the therapeutic index. • Drug overdose and poisoning. • Drug dependence and abuse • An introduction to the pharmacology of the autonomic nervous system
Pharmacodynamics – what the drug does to the body (esp. at receptor level; drug receptor interactions) • Benefit:risk ratio – the therapeutic index. • Drug overdose and poisoning. • Drug dependence and abuse • An introduction to the pharmacology of the autonomic nervous system
Recommended Books • Pharmacology – Rang, Dale Ritter & Flower, 2007. Churchill Livingstone.
Pharmacology • – the science of drugs
Pharmacology • – the science of drugs • - the interaction of drugs with living tissues
Routes of drug administration: 1. Oral
Routes of drug administration: 1. Oral • Advantages: convenient
Routes of drug administration: 1. Oral • Advantages: convenient • Disadvantages: absorption
Routes of drug administration: 1. Oral • Advantages: convenient • Disadvantages: absorption digestion
Routes of drug administration: 1. Oral • Advantages: convenient • Disadvantages: absorption digestion compliance
Routes of drug administration: 1. Oral • Advantages: convenient • Disadvantages: absorption digestion compliance 1st pass effect
2. Sublingual • rapid effect
3. Cutaneous - local - systemic
3. Cutaneous - local - systemic Steady rate of absorption
3. Cutaneous - local - systemic Steady rate of absorption Avoids 1st pass effect
4. Intravenous - bolus - steady infusion
4. Intravenous - bolus - steady infusion - Rapid
4. Intravenous - bolus - steady infusion - Rapid - Avoids problems of absorption
4. Intravenous - bolus - steady infusion - Rapid - Avoids problems of absorption • requires clinical expertise
4. Intravenous - bolus - steady infusion - Rapid - Avoids problems of absorption • requires clinical expertise • E.G. anaesthetics, chemotherapeutic agents
5. Nasal Convenient Rapid effect
5. Nasal Convenient Rapid effect E.G: ADH, GnRH, calcitonin
Intrathecal - into the sub-arachnoid space. - Requires clinical expertise
Intrathecal - into the sub-arachnoid space. - Requires clinical expertise • E.G: anti-cancer drugs, local anaesthetics, antibiotics
7. Rectal. For patients who are: vomiting excessively; in status epilepticus; unconscious.
8. Others….. Eye drops Intramuscular Intraperitoneal
A D M E • Absorption:
A D M E • Absorption: Stomach plasma tissues
Most important factor = lipid solubility • The best absorbed drugs are lipid soluble (hydrophobic; lipophilic),
Most important factor = lipid solubility • The best absorbed drugs are lipid soluble (hydrophobic; lipophilic), • …and are not electrically charged.
Most important factor = lipid solubility • The best absorbed drugs are lipid soluble (hydrophobic; lipophilic), • …and are not electrically charged. • WHY?
However, most drugs are not lipids; most are partly hydrophilic, and partly hydrophobic.
However, most drugs are not lipids; most are partly hydrophilic, and partly hydrophobic. • In addition, drugs are often not pH neutral, but are weak acids or weak alkalis.
A simple example…. • A weak acid such as acetyl salicylic acid HA likes to give away its H (this is the definition of an acid)
HA H+ + A- weak hydrogen base acid ion
HA H+ + A- weak hydrogen base acid ion Acetyl salicylic H+ ion Acetyl Salicylate acid
HA H+ + A- weak hydrogen base acid ion Acetyl salicylic H+ ion Acetyl salicylate acid Uncharged(charged) charged