Transcript Chapter 10 Pharmacology

Pharmacology for Biotech
“The difference between a deadly poison and life saving medicine can be
very small; In fact, it is sometimes merely a question of dosage.”
Dr. R.E. Schultes
Information taken from Healthcare Science Technology
Pharmacology

The study of chemical agents and living
organisms and all aspects of their
interactions i.e. biological response

Xenobiotics: drug substances foreign to the
body such as pollutants, food additives, and
drugs
Pharmacokinetics
Pharmacokinetics
is the study of
the five
processes that
affect the
plasma
concentration of
drugs. (ADMET)
Pharmacokinetics (cont.)

Absorption – the process by which
a drug enters the plasma.


Oral medications are dissolved in the
stomach.
Can be absorbed thru lungs, skin, or
the GI tract
Pharmacokinetics (cont.)

Distribution – where the drug goes after
entering the plasma.



Some of the drug binds to the proteins in the
plasma; some diffuses into other tissues.
Liberation: the process of drug “release” from
dosage form
Metabolic transformation – chemical
changes in a drug that occur after it has
been absorbed into the body.
Pharmacokinetics (cont.)

Elimination or excretion – the process that
removes a drug from the body.


Excreted via skin, lungs, kidneys, intestines
Toxicology – the study of poisons and the
toxicity of drugs to the body


Worry about toxicity if on an antibiotic too long
A negative concern about taking drugs especially if
you will be on them a long time
Routes of Administration
Routes of Administration (ROA) –
the different ways used to get a
drug into the tissues of the body.
Routes of Administration (cont.)

Oral Administration

The most common route. Client swallows a
tablet, capsule, or liquid.

Usually requires 30 to 60 minutes before
producing an effect, or onset of action.

Analgesics: drugs to reduce pain such as
Tylenol as OTC or vicodin or morphine which
are much stronger and need Rx
Routes of Administration (cont.)

Parenteral Administration –
all forms of administration,
other than oral.
 Metered-Dose Inhaler
 Delivers medications
directly to the lungs.
 Rapid action.
 Minimal systemic side
effects.

Nasal spray, suppository,
drops
Routes of Administration (cont.)

Transdermal Patch –
one of the most
consistent and
convenient dosage
forms.
 Remove and discard
old patch.
 Select a site for new
patch.
 Apply the patch.

Topical ointments
Hormone therapies, nicotine patches
Often times this is an anti-itch
Routes of Administration (cont.)

Injections – used when a rapid effect is
needed.
 Intravenous (IV) injection – into the vein
 Subcutaneous (SC) injection – most
frequently given in the upper arm, front of
thigh, or abdomen.
 Intramuscular (IM) injection – normally
given into relatively large muscles of the
shoulder, buttocks, or outer portions of the
thigh.
Take your best guess!
What is the largest volume that can
be given with an SC injection?
Answer:
The largest volume is 1 milliliter (mL).
Dosages
Dosages are usually based
on the weight of an
individual.
Dosages (cont.)

Effects of Individual Differences
on Maintenance Doses

Age, body fat, and diseases that
affect the liver and kidneys may
require altering the dosage of a drug.
Apply Your Knowledge
List the 5 processes of
pharmacokinetics.
Answer:
1. Absorption
2. Distribution
3. Metabolism
4. Elimination or excretion
5. Toxicology
Systems affected by Drugs!




Nervous system
Cardiovascular system
Gastrointestinal system
Endocrine system
What diseases / drugs effect each system

Endocrine System


Hormone treatments for diseases such as Thyroid
disease, human growth hormone levels, etc.
Cardiovascular


Heart disease: Digitalis
Atherosclerosis / high BP: Lipitor and diuretics
(cause kidneys to excrete more water and salt)
What diseases / drugs effect each system

Nervous System




Bells Palsy, Cerebral palsy
Parkinson’s or Alzheimer’s disease
Most nervous disorders are not treated with drugs
Gastrointestinal System



Ulcers: Pepcid, Zantac
Colon cancer, cirrhosis, hepatitis
Diabetes: insulin
How drugs work

Receptors – proteins found inside or outside
the cell; bind to Ligands

Ligands – molecules that bind to receptors
i.e. hormones or neurotransmitters

Types of Ligands



Agonists – activate receptors
Antagonists – de-activate receptors by inhibiting the
binding of agonists
Inverse agonists – reduce cellular activities
How drugs work (cont.)



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Enzymes – proteins that speed up a chemical
reaction
Enzyme inhibitors – bind to enzymes and
decrease activity i.e. herbicides
Enzyme activators – bind to enzymes and
increase activity
Enzyme inhibitor – block substrate from
entering enzyme active site or from
catalyzing the reaction, can alter amino acid
structure
Sources of Drugs

Natural Sources

Pharmacognosy is the study of drugs
made from natural sources, such as
plants and animals.

Plants were the main source of medicine
until the early 1900s, when Sir F. G.
Banting and Charles Herbert Best
extracted insulin from a pancreas and
tested it on diabetic dogs.
Sources of Drugs (cont.)

Natural Sources (cont.)

Problems associated with naturally occurring
drugs:
 Some are broken down very quickly by the
body.
 Some are poorly absorbed into the
bloodstream.
 Isolating a drug from a plant or animal can
be slow, expensive, and may result in
harmful impurities in the drug.
 Naturally occurring products can be
extremely scarce.
Sources of Drugs (cont.)

Microbial organisms


Penicillin, isolated by Sir Alexander
Fleming in 1928, was one of the first
drugs that did not come from a plant
or animal.
Large scale manufacture in what
year?

1943
Sources of Drugs (cont.)

Synthetics and Bioengineering



Medicinal chemistry modifies natural
products by producing them
synthetically or by creating new
products.
Aspirin, synthetically produced today,
was once an extract of willow bark.
Insulin was the first drug to be
produced from genetically altered
bacteria (recombinant)
Sources of Drugs (cont.)

Natural Sources (cont.)

Genetically modified E-coli used to make insulin
Plasmid
containing
human
insulin gene
Bacterial
Chromosome
Cell A
Cell B
Plasmid has been
inserted into the
bacterial cell
Pharmacotherapeutics




Examines the mechanism of action
(MOA) of drugs.
Describes the effects produced by a
drug.
Determines what dose of a drug is
needed to produce a desired effect.
Determines what dose of a drug
produces toxic effects.
Pharmacotherapeutics (cont.)

Mechanisms of Action (MOA)
 Drugs with the same MOA are said to
belong to the same therapeutic class.
 Binding occurs when a drug combines with
a chemical in the body.
 MOA operates on a “lock and key”
principle. The drug is considered the key
and the body chemical the lock.
Pharmacotherapeutics (cont.)

Mechanisms of Action (cont.)
 Binding to and Stimulating a Receptor in the
Body

Receptors – proteins found in cells.
Click for Picture
Pharmacotherapeutics (cont.)

Mechanisms of Action (cont.)
 Binding to and Blocking a Receptor in the
Body
 Some drugs, called antagonists or
blockers, bind to a receptor without
causing a response, thus preventing the
naturally occurring key from binding.
Click for Picture
Pharmacotherapeutics (cont.)

Mechanisms of Action (cont.)
 Inhibiting an Enzyme
 Enzyme inhibitors increase or decrease the
concentration of an enzyme.
Click for Picture
Pharmacotherapeutics (cont.)

A side effect is any effect produced
by a drug that is not the desired
effect.

Local Side Effects
 Occur before a drug is absorbed into
the bloodstream.
Pharmacotherapeutics (cont.)

Systemic Side Effects
 Take place after being absorbed
into the bloodstream.
 May take the form of an allergic
reaction, since drugs are not a
“natural” part of our body.
 Most occur because the drug
affects cells other than the target
cells.
Apply Your Knowledge
Where do drugs come from?
Answer:
1. Natural sources such as plants and animals.
2. Microscopic organisms such as bacteria,
fungi, and molds.
3. Synthetics and bioengineering.
Therapeutic Classes of Drugs

Drugs in a therapeutic class produce
their effect in the same way.

Examples are listed on the following
slides.
Therapeutic Classes of Drugs (cont.)
 Angiotensin Converting Enzyme Inhibitors
 Angiotensin is a naturally occurring protein
in the body. An enzyme called angiotension
converting enzyme (ACE) activates
angiotensin, which, when overactive, causes
high blood pressure, or hypertension.
 ACE inhibitors reduce the production of
angiotensin.
 Representative drugs: Accupril®, Lotensin®,
Prinivil®, Vasotec®, and Zestril®.
 Common side effects include headache and
dizziness.
Therapeutic Classes of Drugs (cont.)
 Beta-1 Blockers
Bind to beta-1 receptors without
stimulating them, preventing epinephrine
(adrenalin) and norepinephrine from
binding.
Representative drugs: Lopressor®,
Tenormin®, Toprol®.
Indications: hypertension, tachycardia or
rapid heartbeat.
Common side effects: dizziness,
drowsiness.
Therapeutic Classes of Drugs (cont.)
 Beta-2 Agonists
 These drugs bind to beta2 receptors on the smooth
muscle cells of the
bronchioles, causing
dilation. Representative
drugs: Ventolin®,
Proventil®, Serevent®,
Alupent®, Brethine®.
 Indications: asthma,
emphysema.
 Common side effects:
tremors, increased heart
rate, and insomnia.
Therapeutic Classes of Drugs (cont.)
 Antihistamines
Antihistamines bind to histamine
receptors, without stimulating
them.
Representative drugs: Allegra®,
Benadryl®, Claritin®, Zyrtec®.
Indications: itching, nasal
congestion, seasonal allergies
such as hay fever.
Common side effects: dry mouth
and drowsiness.
Therapeutic Classes of Drugs (cont.)
 H2 Antagonists
 Bind to H2 receptors, found
only in the stomach, to
decrease the amount of
hydrochloric acid produced.
 Representative drugs:
Tagamet®, Pepcid®, Zantac®.
 Indications:
gastroesophageal reflux
disorder, gastric ulcers,
duodenal ulcers.
 Common side effects:
diarrhea, headache.
Therapeutic Classes of Drugs (cont.)
 Proton Pump Inhibitors
 Drugs that turn off the proton pumps in the
stomach, which reduces stomach acid.
 Representative drugs: Prilosec®.
 Indications: gastroesophageal reflux disorder,
gastric ulcers, duodenal ulcers.
 Common side effects: diarrhea, headache.
Therapeutic Classes of Drugs (cont.)
 Narcotic Analgesics
 Drugs that bind to and stimulate the endorphin
receptors in the spine which inhibit nerve cells
that carry pain to the brain.
 Representative drugs: morphine, codeine,
Demerol®, Vicodin®, Percodan®.
 Indications: severe pain.
 Common side effects: drowsiness, slow and
shallow breathing, constipation.
Therapeutic Classes of Drugs (cont.)
 Nonsteroidal Anti-inflammatory Drugs
 Nonsteroidal anti-inflammatory drugs (NSAIDS)
inhibit the enzyme prostaglandin synthase, which
makes prostaglandins.
 Representative drugs: aspirin, Motrin®, Advil®,
Relafen®, Naprosyn®, Aleve®.
 Indications: mild to moderate pain, inflammation,
fever.
 Common side effects: stomach irritation.
Therapeutic Classes of Drugs (cont.)
 Reverse Transcriptase Inhibitors




Inhibit the activity of the enzyme reverse
transcriptase, which is needed to convert RNA to
DNA.
Representative drugs: AZT, Combivir®, Sustiva®,
Retrovir®.
Indications: HIV infection.
Common side effects: anemia, fever, rash,
headache, lack of energy, nausea, vomiting,
diarrhea, stomach pain, cough, shortness of
breath, sore throat.
Apply Your Knowledge

What type or class of drugs are used to
relieve pain?


What type or class of drugs is given for an
allergic reaction


Analgesics such as Tylenol or morphine
Anti histamines
What type or class of drug is given for an
ulcer?


Proton pump inhibitor such as Prilosec or
H2 antagonist such as Zantac