INTRODUCTION TO PHARMACOLOGY

SULAYMAN ADEMOLA
B.Pharm.,PGD(HSE),Msc(Pharm.),MPH,LLB,
PhD, MCPAN FPCPharm,FIAPH
HOD-PHARMACOLOGY
SENIOR LECTURER/CONSULTANT
PSYCHIATRIST
ISLAMIC UNIVERSITY IN UGANDA,
UGANDA.
demmypharm@gmail.com
demmypharm@yahoo.com
sulaymanademola@iuiu.ac.ug
+256759748448,+256779474562
 PHARMACOLOGY
WHAT IS PHARMACOLOGY
It is the Science of drug action on biological
systems in its entirety.
It has to do with the knowledge of the
sources, chemical properties, biological
effects and therapeutic uses of the drugs.
It is broadly divided into Pharmacokinetics
and Pharmacodynamics
SCOPE OF PHARMACOLOGY
• History - It is of intellectual interest to the physician to know how drugs are
discovered and developed. Often in the past, this was based on folklore or
intelligent observation (e.g. digitalis leaf, penicillin). Nowadays, new drugs are
mostly developed by the organic chemist working with a pharmacologist,
increasingly from basic knowledge about key molecular targets. Usually some sort
of biological screen is used to select among organic molecules for optimum
pharmacological activity.

• 1. Francois Magendie (1783-1855), a French physiologist laid down the dictum

"Facts and facts alone are the basis of science." Experimental procedures
with animals are the testing grounds for determination of drug action.

• 2. Claude Bernard (1813-1878) worked in Magendie's lab, investigated the

plant extract curare and proposed a site of action for this agent.

• 3. Rudolph Buchheim (1820-1879). In 1847 Buchheim established the first

laboratory devoted to experimental pharmacology in the basement of his
home in Dorpat which is known as the cradle of experimental pharmacology .

• .
• 4. Oswald Schmiedeberg (1838-1921). In 1872 Schmiedeberg set up
an
institute of pharmacology in Strasbourg, France (Germany at that time)
which became a mecca for students who were interest in pharmacological
problems.

• 5. J.N. Langley (1852-1925) and Sir Henry Dale (1875-1968) pioneered

pharmacology in England, taking a physiological approach.

• 6. John J. Abel (1857-1938) established the first chair of pharmacology

in the U.S.A. (U. Michigan, 1891) after training in Germany. Able went to
Johns Hopkins in 1893, and trained many U.S. pharmacologists. He is
known as "The Father of American Pharmacology".

• 7. The second world war was the impetus for accelerated research in
pharmacology (the war time antimalarial program) in the U.S., and
introduced strong analytical and synthetic chemical approaches
• Chemistry - Chemical structures of drugs can provide information about
mechanism of action, pharmacokinetics, stability, and metabolic fate.
• 1. Structure-Activity Relationship - A modification of the chemical
structure of a drug may accentuate or diminish its pharmacological
effects, often providing clues as to the mechanism of action. A picture of
the biological reactive site (the receptor) can be developed in such
studies. Also, drugs are metabolized by body systems, which may
convert the parent drug to a more active or a less active form. The drug
structure can be modified to enhance or diminish the rate of metabolic
conversion.

• 2. Sites of Action - The organ or cellular target of drug action.

• 3. Drug Receptors - Macromolecules in cells or cell membranes with

which drugs interact to exert their effects. Usually the interacting forces
are reversible ionic and Van der Waals bonds of relatively low energy,
but
sometimes covalent bonds are formed (e.g. organophosphate
insecticides).
• Pharmacodynamics - The effect of the drug
on the body. Pharmaco-dynamics is the study
of the relationship of drug concentration and
the biologic effect (physiological or
biochemical).
• For most drugs it is necessary to know the
site of action and mechanism of action at the
level of the organ, functional system, or tissue.
• For example, the drug effect may be localized
to the brain, the neuromuscular junction, the
heart, the kidney, etc.
• Often the mechanism of action can be
described in biochemical or molecular terms.
• Pharmacokinetics - The effect of the
body on the drug.
• To produce its characteristic effects, a
drug must be present in appropriate
concentrations at its sites of action.
• Thus, it is important to know the inter
relationship of the absorption, distribution,
binding, biotransformation, and excretion
of a drug and its concentration at its locus
of action.
• Clinical Pharmacology and Therapeutics

• 1. Indications and Therapeutic Uses - Emphasis is placed on the

therapeutic use of drugs for the treatment of disease in clinical
pharmacology, internal medicine and therapeutics. There are
specific clinic disorders or disease entities for which a given drug
may be prescribed and the physician must weigh the potential
benefit of drug use against the risks of adverse effects.

• 2. Contraindications and Factors (e.g., liver disease)May Modify

Drug Action - where detoxification of the drug by the liver is
important. It is important to know that the presence of disease or
organ pathology may influence the actions of a drug. Conditions
such as age, pregnancy, concomitant administration of other drugs
and disease may alter the patient's response to a given drug.

• 3. Posology - Is an archaic term describing dosage regimens.

Consideration of dosage schedules is a part of pharmacokinetics.
• 4. Bioavailability - The fraction of drug administered which is actually absorbed
and reaches the systemic circulation following oral dosing. Preparations of the
same drug by different manufacturers may have a different bioavailability.

• 5. Prescription writing - It is important that the physician write clear, error-free

directions for the drug provider (pharmacist) and for the patient.
• Physicians must guard against prescribing too many drugs, or preparations of
little value.
• Drugs of unproven clinical value should be avoided, as well as potentially toxic
agents if drugs equally effective but less dangerous are available.
• Risk-benefit and cost-benefit should be considered. Drugs may be prescribed by
generic name, since often a less expensive drug product can be obtained in this
way. A particular manufacturer may be specified if the physician has reason to
believe a better or more reliable preparation is available from that manufacturer.

• 6. Drug Nomenclature - In addition to its formal chemical name, a new drug is

usually assigned a code name by the pharmaceutical manufacturer.
• If the drug appears promising and the manufacturer wishes to place it on the
market, a United States Adopted Name (USAN) is selected by the USAN Council
• Toxicology - That aspect of pharmacology that deals with the
adverse effects of chemical agents. Toxicology is concerned not only
with drugs used in therapy but also with the other chemicals that may
be responsible for household, environmental or industrial intoxication.

• 1. Forensic Toxicology - Addresses medicolegal aspects of the use

of chemicals that are harmful to animals or man. Analytical chemistry
and fundamental toxicological principles are hybridized to underlie
this aspect of toxicology.
• Nonetheless accidental poisoning with drugs is a health problem of
major significance. More than 1/4 of the fatalities and about 1/2 of all
poisonings occur in children under 5 years of age.
• All common household articles that are poisonous should be made
unavailable to children, and poisonous rodenticides and insecticides
should not be placed in the home or keep out of reach.

• 2. Clinical Toxicology - Focuses on toxic events that are caused by

or are uniquely associated with drugs or other chemicals.
• Pharmacovigilance - The area of pharmacology that focuses on the effects of drugs
on patient safety. It involves the characterization, detection, and understanding of
adverse events associated with drug administration, including adverse drug
reactions, toxicities, and side effects that arise as a consequence of the short- or
long-term use of drugs.
• Adverse drug reactions, including drug-drug interactions, are estimated to be a
major cause of mortality of in-patients and also lead to significant increases in
duration of hospitalization. No drug is free of toxic effects.
• Some untoward effects of drugs are trivial, but others are serious and may be fatal.
Side effects often are predictable from a knowledge of the pharmacology of a
particular drug.
• Examples of chemicals or drug-induced toxicities are given below:
• 1. Allergic reactions - The number of serious allergic reactions to drugs involving
antigen-antibody reactions is low but when they occur the physician must have
sufficient knowledge to manage these problems.

• 2. Blood dyscrasias - These are very serious and sometimes fatal complications of
drug therapy. They include: agranulocytosis, aplastic anemia, hemolytic anemia,
thrombocytopenia and defects in clotting factors.

• 3. Hepatotoxicity and nephrotoxicity - Because many chemicals and drugs are

eliminated and metabolized by the liver and kidney, damage to these organs is seen
commonly.
• 4. Teratogenic effects - The thalidomide tragedy dramatically emphasized
that drugs may adversely influence fetal development.

• 5. Behavioral toxicity - This is a term used to describe suppression of

normal anxiety, reduction in motivation, impairment of memory and learning,
distortion of judgement, impairment of reflexes, adverse effects on mood, etc.

• 6. Drug dependence and drug abuse - The repeated administration of some

chemicals may lead to drug dependence. Drugs likely to be abused and upon
which drug dependence may develop are the various psychopharmacological
agents such as opiates, barbiturates, amphetamines, nicotine and ethanol.
Dependence on tobacco (nicotine) is also well known.
• 7. Carcinogenesis - Carcinogenesis is a delayed type of toxicity with a
latency of many years.

• 8. Pharmacogenetic toxicities - Certain genetically-predisposed individuals

have a markedly toxic reaction to certain otherwise safe drugs. Examples are
prolonged apnea after succinylcholine, or malignant hyperthermia associated
with anesthetics.
• Basic introduction to units and
conversions
• Physicians need to be able to make
accurate drug calculations in order to safely
prescribe or administer drugs to their
patients.
• It is therefore important that medical
students begin to engage with mathematics
early in their education.
• This brief introduction is aimed at motivating
you to engage and help you develop your
skills to the required level.
 Equivalencies of weight
• UNIT SYMBOL EQUIVALENT SYMBOL
• 1 kilogram (kg)= 1000 grams (g)
• 1 gram (g) = 1000 milligrams mg
• 1 milligram (mg) = 1000 micrograms (mcg
or μg)
• 1 microgram (mcg) = 1000 nanograms
(ng)
• Before performing many drug calculations you will need to convert the
numbers you use in the calculation so that they all appear in the same units.
• You should be familiar with the units as above ,they are the most common in
drug calculation.
• To convert from a smaller unit (e.g. a gram) to a larger unit (e.g. a kilogram),
divide by 1000, so: 5000g ÷ 1000 = 5kg
• To convert from a larger unit (e.g. a gram) to a smaller unit (e.g. a
milligram), multiply by 1000, so: 5g × 1000 = 5000mg
• It is important to be comfortable with unit conversions before progressing to
using a drug calculation formula.
• Basic formula
• There is more than one way to do a drug calculation, but the simplest and
most widely used method
• This isthe basic formula :
• D × Q⁄H = X
• Where:
• D = desired dose
• H = strength available
 What is a drug

A drug is any substance other than food that

when inhaled, injected, smoked, consumed,
absorbed via the skin or dissolved under the
tongue causes physiological changes in the
body.
It is usually intended for diagnosis, prevention,
treatment or management of diseases or
conditions.
ROUTES OF DRUG ADMINISTRATION
• A route of drug administration is the path
by which a drug, fluid, poison or other
substance is taken into the body.
• They are generally classified by the
location at which the substance is applied
or gained entry.
Factors Influencing the Route of
Administration
• A route of administration is a way of getting
a drug onto or into the body
• Drugs come in many different forms:
– designed by pharmaceutical scientists for
administration or application
• Many factors determine the choice of route of
administration
Ease of Administration
• Prescribers assess characteristics to determine
route of administration
– some patients are unable swallow
– very young or older adult patients might have
difficulty swallowing
• avoid solid, oral dose forms in favor of liquid dose
forms or nonoral routes of administration
– oral route of administration is inadvisable for a
patient experiencing nausea and vomiting
Site of Action
• Choice of route of administration is influenced
by desired site of action
• The term local use refers to site-specific
applications of drugs
• The term systemic use refers to the
application of a drug to the site of action by
absorption into the blood and subsequent
transportation throughout the body
– even drugs meant for systemic administration are
usually targeted to a specific site of action
Onset of Action
Onset rate varies with route of administration:
• Oral medications for systemic use must proceed
through a series of steps before they exert their
therapeutic effect (desired pharmaceutical
action on the body)
• Liquid solutions or suspensions work faster than
oral tablets or capsules
– medication is more readily available for absorption
 Onset of Action
• Tablets placed under tongue or between cheek
and gums work quickly
– medication bypasses stomach and liver, goes directly
into bloodstream
• Drugs injected/infused directly into bloodstream
are carried immediately throughout the body
• Topical medications work quickly
– localized therapeutic effects, especially those
• applied to the skin
• inhaled into the lungs
• instilled into the eye
 Duration of Action
• The duration of action is the length of time a drug
gives the desired response or is at the therapeutic
level
• Controlled- /extended-release tablet may last for 12
to 24 hours compared with 4 to 6 hours for same
drug in immediate-release formulation
• Transdermal patches deliver small amounts of a
drug steadily over many hours or even days
• Sustained-duration effect can be achieved by
means of intravenous (IV) infusion
• Injections into the muscle and skin last longer than
injections directly into the bloodstream
 Quantity of Drug
• Sometimes route of administration is chosen
because of the amount of a drug
– a tablet containing a lot of filler (diluent) might be
preferred for a drug containing a very small amount of
active ingredient
• IV infusion is an excellent method for systemic
delivery of large quantities of material
– rapidly diluted in the bloodstream
• IV injections and infusions can deliver a higher
dose of medication to the target site
– important in serious illnesses
 Metabolism by the Liver or
Excretion by the Kidney
• Liver metabolism breaks down active drug to
inactive metabolites for elimination and to
prevent drug accumulation
• The first-pass effect is the extent to which a
drug is metabolized by the liver before reaching
systemic circulation
– influences activity of several drugs
– such drugs have to be given in large oral doses or by
another route of administration to bypass or overcome
metabolism by the liver
Metabolism by the Liver or
Excretion by the Kidney
• Age-related or disease-related changes in liver
or kidney function can cause:
– drug accumulation
– toxicity
• Older patients are often prescribed lower doses
of medication
• If patients are on multiple potent prescription
drugs, there is a risk of a drug-drug interaction
– drug accumulation
– toxic blood levels increases
 Toxicity
• Toxicology is the study of toxic effects of drugs
or other substances on the body
• Physicians must weigh therapeutic benefit
against the risk of toxicity
• Some drugs have a narrow therapeutic-toxic
index called the “therapeutic window”
– very little difference exists in the therapeutic versus
toxic blood level
– laboratory drug levels are ordered if the physician
suspects toxicity
• Toxicity of a drug may affect route of
administration
Oral Routes of Administration

• Oral refers to two methods of administration:

– applying topically to the mouth
– swallowing for absorption along the
gastrointestinal (GI) tract into systemic circulation

• po (from the Latin per os) is the abbreviation

used to indicate oral route of medication
administration
 Oral Dose Forms
• Common dose forms for oral administration
– tablets
– capsules
– liquids
– solutions
– suspensions
– syrups
– elixirs
 Oral Dose Forms
• Sublingual administration is where the dose
form is placed under the tongue
– rapidly absorbed by sublingual mucosa
• Buccal administration is where the dose form is
placed between gums and inner lining of the
cheek (buccal pouch)
– absorbed by buccal mucosa
• Dose forms for sublingual and buccal
administration:
– tablets – lozenges – gum
 Oral Dose Forms
• Capsules are preferred over tablets for patients
with difficulty swallowing
• Water preferred over beverages
to aid in swallowing
• Some dose forms are designed to
be sprinkled on food when
swallowing a solid is difficult
• Liquid doses are swallowed more easily and are
suitable for:
– patients with swallowing difficulties
– small children
 Oral Dose Forms

The oral route is not appropriate for patients

who are unable to swallow.
Advantages and Disadvantages of
the Oral Route
• Ease and safety of administration

• Active ingredient is generally contained in

powders or granules which dissolve in GI
tract

• Sublingual (and buccal) administration has a

rapid onset (less than 5 minutes)
Advantages and Disadvantages of
the Oral Route
• Delayed onset
– dose form must disintegrate before absorption
• Destruction or dilution of drug by
– GI fluids
– food or drink in stomach or intestines
• Not indicated in patients who
– have nausea or vomiting
– are comatose, sedated, or otherwise unable to
swallow
• Unpleasant taste of some liquid dose forms
– must be masked by flavorings to promote compliance
Advantages and Disadvantages of
the Oral Route
• Sublingual (and buccal) administration has
a short duration of action
– less than 30 to 60 minutes
– not appropriate for routine delivery of
medication
• Buccal route may have
– medicinal taste
– local mouth irritation
Topical Routes of Administration

• Topical administration is the application of a

drug directly to the surface of the skin
• Includes administration of drugs to any
mucous membrane
– eye – vagina
– nose – urethra
– ears – colon
– lungs
Topical Dose Forms

Dose forms for topical administration include:

• Skin: • Eye or ear:
– creams – solutions
– ointments – suspensions
– lotions – ointments
– gels • Nose and lungs:
– transdermal patches – sprays and powders
– disks
Topical Dose Forms

Dose forms for topical administration include:

• Vagina: • Rectum:
– tablets – creams
– creams – ointments
– ointments – solutions
– foams
• Urethra:
– inserts
– suppositories
 Topical Dose Forms
• Transdermal administration:
– delivers drug to bloodstream via absorption through
the skin via a patch or disk
• Skin presents a barrier to ready absorption
– absorption occurs slowly
– therapeutic effects last for 24 hours up to 1 week
• Chemicals in the patch or disc force drug
– across membranes of the skin
– into layer where absorption into bloodstream occurs
 Topical Dose Forms

• Ocular administration is the application of a drug

to the eye
• Conjunctival administration is the application of a
drug to the conjunctival mucosa or lining of the
inside of the eyelid
• Nasal administration is the application of a drug
into the passages of the nose
• Otic administration is the application of a drug to
the ear canal
Topical Dose Forms
Rectal dosage forms:
• Suppository
– solid dose form formulated to melt in the rectum at
body temperature and release the active drug
• Creams, ointments, and foams
– used for local effects
• Rectal solutions, or enemas used for
– cleansing the bowel
– laxative or cathartic action
– drug administration in colon disease
Advantages and Disadvantages of
the Topical Route
• Local therapeutic effects
• Not well absorbed into the deeper layers of
the skin or mucous membrane
– lower risk of side effects
• Transdermal route offers steady level of drug
in the system
– sprays for inhalation through the nose may be for
local or systemic effects
Advantages and Disadvantages of
the Topical Route
• The intrarespiratory route of administration is
the application of drug through inhalation into the
lungs, typically through the mouth
– lungs are designed for exchange of gases from
tissues into bloodstream
– usual dose form is an aerosol
– “environmental friendly” propellants now required to
replace chlorofluorocarbons (CFCs)
Advantages and Disadvantages of
the Topical Route
• A metered-dose inhaler (MDI) is a common
device used to administer a drug in the form of
compressed gas through inhalation into the lungs

• A diskus is a newer dosage form to administer

drug to lungs as micronized powder
Advantages and Disadvantages of
the Topical Route
The vaginal route of administration is
application of drug via cream or insertion of
tablet into the vagina
Common dose forms include:
– emulsion foams – sponges
– inserts – suppositories
– ointments – tablets
– solutions
Advantages and Disadvantages of
the Topical Route
• The vaginal route is preferred for:
– cleansing
– contraception
– treatment of infections
• Major disadvantages:
– inconvenience
– “messiness”
Advantages and Disadvantages of
the Topical Route
• The urethral route of administration is
application of drug by insertion into the urethra
• Common dose forms include:
– solutions
– suppositories
• Urethral delivery may be used to treat
– incontinence
– impotence in men
• Disadvantages
– inconvenience
– localized pain
Advantages and Disadvantages of
the Topical Route
Rectal administration is a preferred method when:
• An oral drug might be destroyed or diluted by
acidic fluids in the stomach
• An oral drug might be too readily metabolized
by the liver and eliminated from the body
• The patient is unconscious and needs
medication
• Nausea and vomiting or severe acute illness in
the GI tract make patient unable to take oral
drugs
Advantages and Disadvantages of
the Topical Route

• Rectal administration disadvantages:

– inconvenience
– erratic and irregular drug absorption
Parenteral Routes of Administration
• Parenteral administration is injection or infusion by means
of a needle or catheter inserted into the body
• Parenteral forms deserve special attention
– complexity
– widespread use
– potential for therapeutic benefit and danger
• The term parenteral comes from Greek words
– para, meaning outside
– enteron, meaning the intestine
• This route of administration bypasses the alimentary canal
Parenteral Dose Forms
• Parenteral preparations must be sterile
– free of microorganisms

• To ensure sterility, parenterals are prepared

using
– aseptic techniques
– special clothing (gowns, masks, hair net, gloves)
– laminar flow hoods placed in special rooms
Parenteral Dose Forms
• IV route
– directly into a vein

• Prepared in hospitals and home healthcare

pharmacies
– antibiotics
– chemotherapy
– nutrition
– critical care medications
Parenteral Dose Forms

• Intramuscular (IM) injections

– into a muscle

• Subcutaneous injections
– under the skin

• Intradermal (ID) injections

– into the skin
Parenteral Dose Forms

• Disposable syringes
and needles are used
to administer drugs
by injection
• Different sizes are
available depending
on the type of
mediation and
injection needed
 Advantages and Disadvantages
of the Parenteral Route
• The IV route is the fastest method for delivering
systemic drugs
– preferred administration in an emergency situation
• It can provide fluids, electrolytes, and nutrition
– patients who cannot take food or have serious
problems with the GI tract
• It provides higher concentration of drug to
bloodstream or tissues
– advantageous in serious bacterial infection
Advantages and Disadvantages
of the Parenteral Route

• IV infusion provides a continuous amount of

needed medication
– without fluctuation in blood levels of other routes

• infusion rate can be adjusted

– to provide more or less medication as the situation
dictates
Advantages and Disadvantages
of the Parenteral Route
• Traumatic injury from the insertion of needle
• Potential for introducing:
– toxic agents
– microbes
– pyrogens
• Impossible to retrieve if adverse reaction occurs
– injected directly into the body
Advantages and Disadvantages
of the Parenteral Route
• Intramuscular (IM) and subcutaneous routes of
administration are convenient ways to deliver
medications
• Compared with the IV route:
– onset of response of the medication is slower
– duration of action is much longer
• Practical for use outside the hospital
• Used for drugs which are not active orally
 Advantages and Disadvantages
of the Parenteral Route
• For intramuscular (IM) and subcutaneous routes
of administration, the injection site needs to be
“prepped”
– using alcohol wipe
• Correct syringe, needle, and technique must be
used
• Rotation of injection sites with long-term use
– prevents scarring and other skin changes
– can influence drug absorption
Advantages and Disadvantages
of the Parenteral Route

• The intradermal (ID) route of administration is

used for diagnostic and allergy skin testing
– patient may experience a severe local reaction if
allergic or has prior exposure to a testing antigen
 Administering Parenteral
Medications
• IV injections and infusions are introduced directly
into the bloodstream
– must be free of air bubbles and particulate matter
– introduction of air or particles might cause embolism,
blockage in a vessel, or severe painful reaction at the
injection site
Intravenous Injections or
Infusions
• Fast-acting route because the drug goes
directly into the bloodstream
– often used in the emergency department and in
critical care areas

• Commonly used
– for fluid and electrolyte replacement
– to provide necessary nutrition to the patient who is
critically ill
Intravenous Injections or
Infusions
• Intravenous (IV) injections are administered
at a 15- to 20-degree angle
 Intramuscular Injections

• Care must be taken with deep IM injections to

avoid hitting a vein, artery, or nerve

• In adults, IM injections are given into upper, outer

portion of the gluteus maximus
– large muscle on either side of the buttocks

• For children and some adults, IM injections are

given into the deltoid muscles of the shoulders
Intramuscular Injections

• Typical needle is 22- to

25-gauge ½- to 1-inch
needle
• Intramuscular (IM)
injections are
administered at a 90-
degree angle
– volume limited to less than
3 mL
 Intramuscular Injections
• Used to administer
– antibiotics
– vitamins
– iron
– vaccines
• Absorption of drug by IM route is unpredictable
– not recommended for patients who are unconscious or
in a shocklike state
 Intradermal Injections
• Given into capillary-rich layer just below
epidermis for
– local anesthesia
– diagnostic tests
– immunizations
Intradermal Injections

• Examples of ID injections include

– skin test for tuberculosis (TB) or fungal infections
• typical site is the upper forearm, below the area where
IV injections are given
– allergy skin testing
• small amounts of various allergens are administered to
detect allergies
• usually on the back
 Subcutaneous Injections
• Administer medications below the skin into the
subcutaneous fat
– outside of the upper arm
– top of the thigh
– lower portion of each side of the abdomen
– not into grossly adipose, hardened, inflamed, or swollen
tissue
• Often have a longer onset of action and a longer
duration of action
– compared with IM or IV injection
Subcutaneous Injections

• Insulin is given using 28- to 30-gauge short

needles
– in special syringe that measures in units
• Insulin is administered following a plan for site
rotation
– to avoid or minimize local skin reactions
• Absorption may vary depending on
– site of administration
– activity level of the patient
Subcutaneous Injections

• Medications administered by this route include:

– epinephrine (or adrenaline)
• for emergency asthmatic attacks or allergic reactions
– heparin or low molecular–weight heparins
• to prevent blood clots
– sumatriptan or Imitrex
• for migraines
– many vaccines
Subcutaneous Injections

• Normally given with the syringe held at a 45-

degree angle
– in lean older patients with less tissue and obese
patients with more tissue, the syringe should be held
at more of a 90-degree angle
• Correct length of needle is determined by a skin
pinch in the injection area
– proper length is one half the thickness of the pinch
Subcutaneous Injections

• Given at a 45-degree
angle
– 25- or 26-gauge needle,
3/8 to 5/8 inch length
• No more then 1.5 mL
should be injected into
the site
– to avoid pressure on
sensory nerves causing
pain and discomfort
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