Naming and Classification of
Drugs
1
Naming and Classification of Drugs
• Every drug has at least three names
• Chemical Name
• Generic Name
• Trade Name
• This system is very confusing and could lead to the
patient receiving the same drug more than once
• Patient knows the drug by two different names and do
not realize that it is the same drug
2
Chemical Name
3
Chemical Name
• Not used by health care providers
• Describes the chemical structure of the drug.
• This is usually irrelevant to health care
practitioners and patients because we want to
know what the drug does, not its structure.
• Drugs with different chemical structures can do the
same thing.
4
Generic Name
• Most important name
• Constant, printed on the
label or bottle, not
capitalized
• Assigned to the drug when it is
first given to humans.
• The drug is always known by this
generic name.
• The generic name printed on a
bottle or in an advertisement
might be in parentheses and is
not capitalized.
• Sometimes generic names are
hard to say.
• Only one per drug
5
Trade Name
7
Trade Name
• This name is given to the drug by the drug
company that markets it.
• If more than one drug company markets a
particular drug, it will have a different name
for each company.
• This name is capitalized.
8
Acetaminophen
9
Chemical Structure
Chemical Name N-Acetyl-para-aminophenol
Generic Name Acetaminophen
Trade Name Acephen, Aceta, Anacin-3, Apacet, Arthritis Pain
Formula Aspirin Free, Aspirin Free Pain Relief,
Banesin, Bromo Seltzer, Dapa, Datril, Dolane,
Dorcol Children’s Fever & Pain Reducer, Feverall,
Genapap, Genebs, Halenol, Liquiprin Elixir, Meda
Tab, Myapap, Neopap, Oraphen-PD, Panadol,
Panex, Panex 500, Phenaphen Caplets, Snaplets-
FR Granules, St. Joseph Aspirin-Free for Children,
Suppap-325, Tapanol Extra Strength, Tempra,
Tylenol
10
Lehne, RA, Pharmacology for Nursing Care, 6th ed., 2007, Elsevier, p. 19
In the drugstore, you see pill bottles with the
following names:
1. Advil (ibuprofen) 200 mg
2. Ibuprofen, 200 mg
3. Motrin (ibuprofen) 200 mg
4. Nuprin (ibuprofen) 200 mg
Generic vs. Trade Names
12
Generic vs. Trade Names
• Generic names are international and avoid confusion.
• In clinical practice, trade names might be used but
you should always try to look at the generic name too.
• That way, you may avoid giving the same drug twice.
13
Methods of Classifying Drugs
15
Methods of Classifying Drugs
• According to their use (antihypertensives, for instance):
• This may be confusing because many drugs have more than one
use.
• However, this is a classification system used by many people
• One of the most common ways to classify drugs
• According to their mechanism of action:
• This is the most useful classification since it explains all the
actions of the drug
• According to their chemical structure:
• This is of limited usefulness for health care providers
16
Dosage form of Drugs
&
Route of drug administration
By Abubakar salisu fago.
Drug substance are seldom administer alone; rather they are given as part of
formulation in combination with one or more non-medicinal agents that serve
varied and specialized Pharmaceutical functions. Selective uses of non
medicinal agent referred to as pharmaceutical ingredients or excipients,
produces dosage form of various types.
Pharmaceutical ingredients solubilized, suspend, thicken, dilute, emulsify,
stabilized, preserve, color, flavor and fashioned medicinal agent into efficacious
and appealing dosage forms.
Dosage form is mixture of medicinal substance and excipients together so that
they designed in definite form , size , shape, color and in appearances. Dosage
form is the way of identifying the drug in its physical form. In determining
dosage form, FDA examines such factors as
(1) physical appearance of the drug product,
(2) physical form of the drug product prior to dispensing to the patient,
(3) the way the product is administered,
(4) frequency of dosing, and
(5) how pharmacists and other health professionals might recognize and
handle the product."
Each type of dosage form is unique in physical and pharmaceutical characteristics.
Depending on the type of administration they come in several types
Solid
Semi-solid dosage forms
Solid dosage forms
1. Ointments
1. Powders
2. Creams
2. Granules
3. Liniments
3. Tablets
4. Suppository
4. Capsules
5. Gel/ jelly
5. Modified release dosage
6. Paste
forms (Tablet/Capsul)
7. Poultices
8. Aerosols
6. Lozenges ( torches)
9. Transdermal Drug delivery
system
Non–sterile Liquid dosage forms
11. Linctus
1. Syrup
12. Lotions
2. Solution
13. Mixture Sterile dosage forms
3. Tincture
4. Suspension 1. Injectables
5. Emulsion 2. Intravenous bolus
6. Lotion dosage
7. Elixir 3. Drops ( Eye & Ear)
8. Draughts
9. Enemas
10. Gargles
Powders: oral unite dosage form that
nowadays rarely prepared Surgical dusting powders;
extemporaneously These are used in body cavity and major
Powder may be prescribed in the form of wounds. They often contain
1. Bulk powders for (oral) internal use- antibacterial agents.
eg. Eg. Chlorhexidine powders
Gregory powder ( compound BPC) Hexachlorphen powders
Heavy Mg carbonate- 325g Neomycin sulfate powders
Light Mg carbonate 325 g
Rhuberb in powder- 250g Neomycine
Ginger in powder- 100g sulfate, polymaxin
B and
2. Bulk powder for external use- Dexomethasone
dusting powder and insufflations
Dusting powder two types ( free flowing
fine powder for external uses
Medical- these are used for superficial skin Some times, oral solution and syrup or
condition and rarely require to be sterile. even I.V preparation dispense in the
However they should be free from form of powder
dangerous pathogens. Thet are not
intended to use in open wounds. Eg. Paracetamol dry syrup
Eg. Light kaoline, talc, starch and zinc oxide Cephadoxile dry syrup
( they require to add vehicle when use)
Granules:
Solid dosage form oral preparation for large volume of medicaments
where the active ingredients are compressed together with
excipients to form suitable granules and passed through suitable
sieve.
Eg. Methyl cellulose granules
Sodium Amino salicylate ( 6-12gm) for TB
Advantages of granules:
a. Some time it is difficult to find satisfactory presentation of
medicament with large dosages.
b. Tablet and capsule may be impractical because of size and number
of frequency
c. Liquid dosage forms are avoided due to instability in moisture.
d. Administration of powder form is difficult due to unpleasant test
e. Suitable amount of coloring, flavoring and sweetening agent can
be included.
Tablets:
Solid dosage form where powders are moulded into tablets. They
are flat, circular dices usually contain a potent medicament mixed
with sucrose, lactose, dextrose or any other suitable diluents along
with sufficient binding, coloring and flavoring agents. They are
intended for oral use, require prior dissolution upon contact with
moisture of the stomach.
Capsules:
Solid dosage form intended for oral
administration containing active ingredients
along with suitable fillers. They are two
types.
1. Hard gelatin capsules:
They consist a cylindrical body and cap, both
with hemispherical ends, and are made from 2. Soft gelatin capsules: are for solid, liquids
gelatin and water with added preservatives. and semisolid liquids. They may be spherical ,
Although they are quite hard, they soften ovoid or cylindrical. In addition to the
and dissolve after swelling with water ingredients of hard capsules, they contain
glycerol which provide the flexibility.
Modified Release dosage forms (Tablet/Capsule)
In contrast to conventional ( Immediately release)
forms, modified –release products provide either
delayed release or extended release of drugs. Most
delayed release products are enteric coated tablets
or capsules designed to pass through the stomach
unaltered, later to release their medication within
the intestinal tract.
Delayed release product are used either to protect
the substance from destruction by gastric fluids or
to prevent stomach distress.
Extended release Products are designed to release
their medication in a controlled manner, at
predominant rate, duration and location to achieve
and maintain optimum therapeutic blood levels of
drugs.
Lozenges: (torches)
These are solid preparation
consisting mainly sugar and
gum. Gum uses for increasing
the hardness of preparation
thus ensure slow release of
medicaments. They are use to
medicate the mouth and throat
and for slow administration of
indigestion and cough
remedies.
Semisolid Dosage forms
Ointments: are semi-solid greasy
preparation for application to the skin or
mucosa. The base is usually anhydrous
and containing medicaments in solution
or suspension.
They are generally used for their
a. emollient effects
b. protection effect of lesions
c. topical application of medications
eg.
Acne- Sulphur or resorcinol ointment
Antibiotic- bacitracine, chlortetracycline
Anti-inflammatory- Betamethasone
Anti-septic- Zinc oxide
Dandruffs- Salicylic acid
Counter irritant- Capcisin
Creams:
• These are semisolid emulsion for
external use. There are two kinds,
• aqueous and
• oily cream, in which the emulsion
are Oil in Water (O/W) or Water
in Oil (W/O). The oil in water type
are relatively non-greasy.
Cream are of two type cold cream and
vanishing creams. Vanishing cream is an
oil in water type of emulsion whereas
cold cream is of water in oil type of
emulsion. They also differ in their pH.
vanishing cream is of neutral to slightly
acidic pH but cold cream is of neutral
pH. Vanishing creams are easily
washable but cold creams can not be
Drug Overdose
• Self administration of a drug in excess OR in
combination with other agents to the point where
poisoning occurs.
• It can be
Deliberate OR Accidental
Paracetamol Overdose
• Most common drug taken in overdose
• Few symptoms or early signs
• As little as 12g can be fatal
• Hepatic and renal toxin
– Centrolobular necrosis
• More toxic if liver enzymes induced or reduced
ability to conjugate toxin
Paracetamol Metabolism
CHANNELS OF
DRUG
ADMINISTRATION
ENTERAL PARENTERAL TOPICAL
ENTERAL
ORAL
SUBLINGUAL
BUCCAL
RECTAL
ORAL ROUTE
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
Advantages
Convenient - can be self- administered, pain free,
easy to take
Absorption - takes place along the whole length of
the GI tract
Cheap - compared to most other parenteral routes
ORAL
Disadvantages
Sometimes inefficient - only part of the drug may
be absorbed
First-pass effect - drugs absorbed orally are
initially transported to the liver via the portal
vein
irritation to gastric mucosa - nausea and vomiting
ORAL
Disadvantages cont.
destruction of drugs by gastric acid and digestive
juices
effect too slow for emergencies
unpleasant taste of some drugs
unable to use in unconscious patient
First-pass Effect
The first-pass effect is the term used for the
hepatic metabolism of a pharmacological
agent when it is absorbed from the gut and
delivered to the liver via the portal
circulation. The greater the first-pass effect,
the less the agent will reach the systemic
circulation when the agent is administered
orally
First-pass Effect
Oral Dosage Forms
Common dose forms for oral administration
tablets
capsules
liquids
solutions
suspensions
syrups
elixirs
SUBLINGUAL ROUTE
Sublingual administration is
where the dosage form is
placed under the tongue
rapidly absorbed by
sublingual mucosa
SUBLINGUAL ROUTE
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ADVANTAGES
ECONOMICAL
QUICK TERMINATION
FIRST-PASS AVOIDED
DRUG ABSORPTION IS QUICK
DISADVANTAGES
UNPALATABLE & BITTER DRUGS
IRRITATION OF ORAL MUCOSA
LARGE QUANTITIES NOT GIVEN
FEW DRUGS ARE ABSORBED
BUCCAL ROUTE
Buccal administration is
where the dosage form
is placed between
gums and inner lining
of the cheek (buccal
pouch)
absorbed by buccal
mucosa
BUCCAL ROUTE
ADVANTAGES
– Avoid first pass effect
– Rapid absorption
– Drug stability
DISADVANTAGES
– Inconvenience
– advantages lost if
swallowed
– Small dose limit
RECTAL ROUTE
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ADVANTAGES By Suppository or
USED IN CHILDREN
Enema
LITTLE OR NO FIRST PASS EFFECT
USED IN – E.g. aspirin,
theophylline,
VOMITING/UNCONSCIOUS
HIGHER CONCENTRATIONS RAPIDLY ACHIEVED
chlorpromazine
DISADVANTAGES
INCONVENIENT
ABSORPTION IS SLOW AND ERRATIC
IRRITATION OR INFLAMMATION OF RECTAL
MUCOSA CAN OCCUR
Rectal
1. unconscious patients and children
2. if patient is nauseous or vomiting
3. easy to terminate exposure
4. absorption may be variable
5. good for drugs affecting the bowel such
as laxatives
6. irritating drugs contraindicated
SYSTEMIC-PARENTERAL
Parenteral administration is
injection or infusion by means of
a needle or catheter inserted into
the body
The term parenteral comes from
Greek words
para, meaning outside
enteron, meaning the intestine
This route of administration
bypasses the alimentary canal
SYSTEMIC-PARENTERAL
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INJECTABLES
I. INTRAVENOUS
II. INTRAMUSCULAR
III. SUBCUTANEOUS
IV. INTRA-ARTERIAL
V. INTRA-ARTICULAR
VI. INTRATHECAL
VII. INTRADERMAL
INHALATION - Absorption through the lungs
INTRAVENOUS
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ADVANTAGES
BIOAVAILABILITY 100% DISADVANTAGES
DESIRED BLOOD
CONCENTRATIONS ACHIEVED IRRITATION & CELLULITIS
LARGE QUANTITIES THROMBOPHELEBITIS
VOMITING & DIARRHEA REPEATED INJECTIONS NOT
EMERGENCY SITUATIONS ALWAYS FEASIBLE
FIRST PASS AVOIDED LESS SAFE
GASTRIC MANUPALATION TECHNICAL ASSISTANCE
AVOIDED REQUIRED
DANGER OF INFECTION
EXPENSIVE
LESS CONVENIENT AND
PAINFUL
INTRAMUSULAR ROUTE
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ADVANTAGES
ABSORPTION
REASONABLY UNIFORM
RAPID ONSET OF
ACTION
MILD IRRITANTS CAN BE DISADVANTAGES
GIVEN
FIRST PASS AVOIDED ONLY UPTO 10ML DRUG
GASTRIC FACTORS CAN GIVEN
BE AVOIDED LOCAL PAIN AND ABCESS
EXPENSIVE
INFECTION
NERVE DAMAGE
SUBCUTANEOUS
Injected under the skin.
Absorption is slow, so action is prolonged.
IMPLANT :a tablet or porous capsule is inserted into
the loose tissues by incision of the skin, which is
then stiched up.
example : certain hormonal drugs
INTRA-ARTERIAL
Rarely used
Anticancer drugs are given for localized effects
Drugs used for diagnosis of peripheral vascular
diseases
INTRA-ARTICULAR
injections of antibiotics
and corticosteroids are
administered in
inflammed joined
cavities by experts.
example: hydrocortisone
in rheumatoid arthritis
INTRADERMAL
drug is given within skin layers
(dermis)
Painful
Mainly used for testing sensitivity
to drugs.
e.g. penicillin, ATS (anti tetanus
serum)
INOCULATION :administration of
vaccine (like small pox vaccine )
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 Dosage Forms
Dose forms for topical administration include:
Skin:
creams • Eye or ear:
ointments – solutions
lotions – suspensions
gels – ointments
transdermal patches • Nose and lungs:
disks – sprays and powders
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
Transdermal
absorption of drug through skin (systemic action)
i. stable blood levels
ii. no first pass metabolism
iii. drug must be potent or patch
becomes too large
Route for administration
-Time until effect-
intravenous 30-60 seconds
endotracheal 2-3 minutes
inhalation 2-3 minutes
sublingual 3-5 minutes
intramuscular 10-20 minutes
subcutaneous 15-30 minutes
rectal 5-30 minutes
ingestion 30-90 minutes
transdermal (topical) variable (minutes to hours)
SELECTION OF ROUTE
The ROA is determined by :
the physical characteristics of the drug
the speed which the drug is absorbed and/
or released
the need to bypass hepatic metabolism
to achieve high conc. at particular sites
Accuracy of dosage
Condition of the patient
Sublingual/Buccal
Some drugs are taken as smaller tablets which are
held in the mouth or under the tongue.
Advantages
rapid absorption
drug stability
avoid first-pass effect
Sublingual/Buccal
Disadvantages
inconvenient
small doses
unpleasant taste of some drugs
