Transcript Routes of Drug Administration and Dosage

Routes of Drug Administration and
Dosage Formulations
Routes of administration
Chapter Topics
•
•
•
•
•
•
•
Routes of administration
Oral route of administration
Transmucosal route of administration
Topical route of administration
Inhalation route of administration
Parenteral route of administration
Drug delivery systems
Learning Objectives
• Differentiate between the terms route of
administration, dosage form, and drug delivery system.
• Explain the qualities of oral, topical, and parenteral
dosage forms.
• Identify inactive ingredients and various coatings of
tablets.
• Differentiate between a suspension and an emulsion.
• Identify dosage formulations utilizing the transmucosal
route of administration.
• Define the emulsion characteristics of topical products.
• Explain the advantages and disadvantages of oral,
topical, and parenteral dosage formulations.
Learning Objectives (continued)
• Discuss the importance of syringe selection for a
diabetic patient.
• Contrast the advantages and disadvantages of insulin in
multi-dose vials and prefilled insulin syringes.
• Understand the stability and expiration dates of insulin
at room temperature and refrigerated temperatures.
• Demonstrate correct techniques for administration of
eyedrops, eardrops, metered-dose inhalers, and
various parenteral injections.
• Differentiate among enteric-coated, sustained-release,
and extended-release dosage formulations.
Routes of Administration
• Route of administration
– A way to get a drug into
or onto the body
– Oral, transmucosal,
topical, inhalation,
parenteral
• Dosage form
– The physical
manifestation of a drug
that is designed to deliver
the medication
– Tablet, capsule,
suspension, ointment,
cream
Oral Dosage Forms
• Tablets
Although tablets and
capsules may have
distinctive markings and
colors, the pharmacy
technician should rely on
the National Drug Code
(NDC) number–not the
appearance of the
medication–to confirm the
medication’s identity.
– Solid dosage form produced
by compression
– Contains one or more active
ingredients along with
inactive ingredients called
excipients
– Types of tablets
•
•
•
•
•
Compression tablet
Multiple compression tablet
Caplet
Chewable tablet
Oral disintegrating tablet
(ODT)
Oral Dosage Forms (continued)
Inert Tablet Ingredients and Their Uses
Oral Dosage Forms (continued)
• Tablet coatings
– Sugar-coated tablet (SCT)
• Layer of sugar protects the
medication and improves
appearance and flavor
• Can be crushed but loses its
taste-masking effects
– Film-coated tablet (FCT)
• Layer of polymer that may
be either soluble or
insoluble in water
• Some prevent serious GI
effects
• Can be crushed but loses its
taste-masking effects
The oral route is not
appropriate for patients who
are experiencing nausea or
vomiting.
Oral Dosage Forms (continued)
• Capsules
– Active ingredient in the form of a granular
powder or liquid gel enclosed by gelatin shell
• Powders
– Active ingredient in the form of fine particles
• Effervescent salts
– Granules or coarse powders containing active
ingredient plus sodium bicarbonate combination
– Fizz when dissolved in water
Oral Dosage Forms (continued)
• Solutions
– Active ingredients are
completely dissolved in a liquid
– Elixir
• Clear, sweetened, flavored
solution containing water and
ethanol
– Syrup
• An aqueous solution thickened
with a large amount of sugar
• Preferred vehicle for pediatric
medications
Because of their high sugar
content, syrups should be
used cautiously with diabetic
patients.
Oral Dosage Forms (continued)
Suspension
Emulsion
Solid particles of active
A mixture of two immiscible
ingredients mixed with, but substances
not dissolved in, liquid
Considered a dispersion
Contains an emulsifying
agent that stabilizes it
An incomplete mixture of
solid and liquid
An incomplete mixture of
two liquids
Oral Dosage Forms (continued)
• Colloid
– A mixture having physical
properties between those
of a solution and a fine
suspension
• Magma–has ultrafine
particles
• Microemulsion–one liquid
dispersed in another, clear
because of the fine size of
the dispersed droplets
Oral Dosage Forms (continued)
Dosage form
Advantages
Disadvantages
Tablets
Low cost, precise dosing,
increased palatability,
dose can be manipulated if
scored
Delayed onset of action,
destruction of drug by GI fluids,
local GI side effects, delayed
absorption of food in stomach,
ineffective for patients unable to
swallow
Delayed-release
(DR) tablets
Longer duration of action, fewer
side effects, reduced dosing
schedule
Cannot be split or crushed,
slower onset of action,
prolonged side effects, more
expensive
Capsules
Easier to swallow, more rapid
dissolution, faster onset of
action, contents of some can be
sprinkled over food or mixed
with water
Dose cannot be manipulated
Liquids
Faster onset of action, easy
administration, individualized
dosing
Less stable, sugar content a
problem for diabetic patients,
unpleasant taste
Oral Dosage Forms (continued)
• Dispensing and administration pearls
– Delayed-release and enteric-coated tablets
should not be crushed.
– Some capsules may be opened up and sprinkled
on food.
– Expiration of most antibiotic suspensions is 7 to
10 days at room temperature, 14 days in the
refrigerator.
– Suspensions should be shaken well.
– Oral syringes, medications cups, or droppers
should be used to measure liquid medications.
In the Know: True or False
• A solubilizer promotes adhesion of the materials
in a tablet.
false
• The pharmacy technician should rely on the
appearance of a tablet to confirm its identity.
false
• In a suspension, solid particles of active
ingredients are mixed with but not dissolved in
liquid.
true
Transmucosal Dosage Forms
• Allows drug to be
absorbed through the
permeable mucous
membranes of the mouth,
eyes, ears, nose, rectum,
vagina, or urethra
• Sublingual medications
– Tablet placed under the
tongue where it is rapidly
absorbed by blood vessels
– Example: nitroglycerin
tablets
Sublingual nitroglycerin
tablets are sensitive to air and
light and, consequently, will
lose potency over a certain
period. These tablets should
be kept in their original
container and replaced every
6 months.
Transmucosal Dosage
Forms (continued)
• Buccal medications
̶ Absorbed by blood
vessels in the lining
of the mouth
̶ Examples: sore
throat lozenges,
nicotine gum
If nicotine gum is
chewed vigorously, too
much nicotine can be
released, causing
unpleasant side effects.
Therefore, pharmacy
personnel should
instruct patients on the
proper chewing
technique for nicotine
gum.
Transmucosal Dosage
Forms (continued)
• Ophthalmics
– Sterile solutions, suspensions, or ointments
administered to one or both eyes
Transmucosal Dosage
Forms (continued)
• Ophthalmics
– Multiple-dose products
must contain a
preservative.
– Unit-of-use packages do
not require a preservative.
Unused ophthalmic
medication should be
discarded 30 days after the
container is opened.
Manufacturer expirations do
not apply once a patient has
opened the medication.
Transmucosal Dosage
Forms (continued)
• Otics
– Nonsterile solutions or suspensions
administered into one or both ears
Transmucosal Dosage
Forms (continued)
• Nasal sprays/solutions
– Administered to the passages of the nasal
cavity
– Spray emits a fine dispersion of liquid
© Paradigm Publishing, Inc.
Transmucosal Dosage
Forms (continued)
• Suppositories and solutions
– A semisolid dosage form
that melts at body
temperature and releases an
active drug
Pharmacy personnel should
remind patients who are
using suppositories to
remove the foil packaging
prior to insertion.
Some suppository
ingredients, such as
phenylephrine (used to
shrink hemorrhoids) must
be used with caution in
patients with hypertension
and other diseases. Refer
patients to pharmacist to
assist in product selection.
Transmucosal Dosage
Forms (continued)
• Suppositories and
solutions (continued)
̶
Rectal suppositories,
solution, enemas
• May be used locally for
cleansing the bowel, for
laxative action, for
hemorrhoids, or for colon
disease
• May be used systemically
• Used sometimes if patients
cannot take medications by
mouth
Refrigeration is
necessary to store most
rectal suppository
medications.
Transmucosal Dosage
Forms (continued)
• Suppositories and
solutions
– Vaginal suppositories and
solutions
• Used for local effect such as
cleansing, contraception,
hormone replacement
therapy, or treatment of
infections
– Urethral suppositories and
solutions
• Used for cancer treatment,
incontinence, or impotence
in men
Transmucosal Dosage
Forms (continued)
Dosage form
Advantages
Disadvantages
Sublingual
Rapid onset of action
Short duration of action
Buccal
Rapid onset of action, fewer
side effects
Unpleasant taste, local mouth
irritation, “dose dumping” if
directions not followed
Ophthalmics, otics, Fast onset of action, localized
and nasal
therapeutic effect
sprays/solutions
Nasal
solutions/sprays
Some have less systemic side
effects than oral form
Some have systemic side effects
Suppositories and
solutions
Depending on the medication,
can be used for either local or
systemic action
Patient inconvenience and
discomfort, premature
expulsion of the suppository,
irregular drug absorption
Transmucosal Dosage
Forms (continued)
• Dispensing and administration pearls
– A transmucosal fentayl citrate (OTFC) lollipop should
be sucked for about 15 minutes.
– Some ophthalmics require refrigeration but should
be warmed to room temperature when given.
– When giving antibiotic opththalmics, the tube or
dropper should not touch the infected area.
– Patients should be warned not to used OTC nasal
decongestants for more than three days.
– Lubrication of a rectal suppository with petroleum
jelly should ease its administration.
In the Know: Fill in the Blank
• Sublingual medications are placed under the
patient’s __________.
tongue
• Eyedrops and ointment should be applied to the
____________ ____.
conjunctival sac
• Dose dumping if directions not followed may
occur with _________ medications.
buccal
Topical Dosage Forms
• Used to apply a drug
directly to the surface
of the skin
• Ointments, pastes, and
plasters
– Ointments
• Water-in-oil (W/O)
emulsion: contains a
small amount of water
dispersed in oil
• Usually have an oily feel
Topical Dosage Forms (continued)
• Ointments, pastes, and plasters
– Pastes
• Contains more solid materials than an ointment,
has a dense consistency
– Plasters
• A solid or semisolid that adheres to the body and
contains a backing material
Topical Dosage Forms (continued)
• Creams, lotions, and gels
– Creams
• Oil-in-water (O/W) emulsion - contains a small
amount of oil dispersed in water
• Become invisible once applied to the skin
– Lotions
• Easily absorbed and can cover large areas of the body
– Gels
• Contain fine or ultrafine particles in a liquid
• Apply evenly and leave a dry coat of the medication in
contact with the area
Topical Dosage Forms (continued)
Dosage form
Advantages
Topical
Fast onset of action, few
formulations , in systemic side effects
general
Disadvantages
Some absorbed
systemically, risk of local
hypersensitivity
Ointments
Maintain moisture (good for Appearance, greasy residue
dry areas of skin), longer
contact time with skin
Creams, lotions,
gels
Apply smoothly to the skin,
more readily absorbed,
more cosmetically
acceptable, less systemic
side effects from vaginal
creams
Lotions
Easily absorbed, can cover
large areas of the body,
effective for hairy areas
Vaginal creams can be
messy
Topical Dosage Forms (continued)
• Dispensing and administration pearls
– Gloves should be worn when applying nitroglycerin,
capsaicin, and potent topical steroids.
– Topical steroids should be applied sparingly and not
covered with bandages.
– Some topical steroids available in different salts
which are not interchangeable.
In the Know: True or False
• An ointment is a W/O emulsion.
true
• A cream is an O/W emulsion.
true
• Ointments are often more cosmetically
acceptable than creams.
false
Inhalation Dosage Forms
• Inhaled via the oral
respiratory route
• Metered-dose inhalers
(MDI)
– Handheld, propellantdriven device which
provides a specific
measured amount of
medication
– Examples: Ventolin,
Proventil, Advair HFA
Inhalation Dosage Forms
(continued)
Proper Technique for Administration of an MDI
Inhalation Dosage Forms
(continued)
• Sterile solutions and
nebulizers
– Delivered as a mist
through an atomizing
machine called a nebulizer
– Sterile water for injection
(SWI) and normal saline
(NS) used as vehicles to
deliver medication into the
lung
– Device will aerosolize both
the medication and the
vehicle
Inhalation Dosage Forms
(continued)
• Micronized powders and
nonaerosolized inhalers
– Breath-activated powder
used to avoid propellants
– Uses a discus to administer
a higher concentration of
drug as a micronized
powder into the lungs
– Provides a controlled
release of active ingredient
Inhalation Dosage Forms
(continued)
Dosage form
Advantages
Disadvantages
MDI
Rapid onset of action
May be difficult to
administer for patients with
poor hand-eye coordination
Nebulized
medication
Higher dose of medication
delivered, faster onset of
action
Larger amount of
medication may lead to
higher risk of side effects
Inhalation Dosage Forms
(continued)
• Dispensing and administration pearls
– If taking more than one MDI, the immediate-acting
drug should be given first followed by the second
one 5 to 10 minutes later.
– Spacer devices recommended for pediatric and
elderly patients
– After administration of an inhaled steroid, the
mouth should be rinsed.
– Mouthpiece of inhaled steroid MDI should be
washed with soap and water at least twice weekly.
Parenteral Dosage Forms
• A sterile or microbial-free
solution that is administered
with a needle inserted
through one or more layers of
the skin
• Greek roots: Para means
beside, enteron means
intestine. This route of
administration goes “beside”
rather than through the GI
tract, thereby bypassing it.
Parenteral Dosage Forms
(continued)
• Intravenous (IV)
– Administered through a vein directly into the
bloodstream
– Examples: antibiotics, chemotherapy, nutrition,
critical care medications
• Intramuscular (IM)
– Administered into muscle
– Examples: EpiPen, flu vaccine, antipsychotic
medications
Parenteral Dosage Forms
(continued)
• Subcutaneous
– Administered under the skin
– Examples: insulin, pneumonia
and shingles vaccines, EpiPen
(either IM or subcutaneous)
• Intradermal (ID)
– Administered into the dermal
layer of the skin
– Examples: allergy testing,
diagnostic testing
(tuberculosis), local anesthesia
Although the abbreviations
SQ and SC are still used, this
practice should be
discouraged due to the risk
of medication error.
Parenteral Dosage Forms
(continued)
Parenteral Dosage Forms
(continued)
• Dispensing and administration pearls
– Syringe
• A calibrated device used to draw up, measure,
and deliver medication through a needle
• Insulin syringes available as 30 units (0.3 ml), 50
units (0.5 ml), and 100 units (1 ml)
• Concentration of insulin vials is 100 units/ml
• Proper size of insulin syringe determined by the
dose
Parenteral Dosage Forms
(continued)
Common Types of Syringes
(a) Insulin syringes in 30 unit, 50 unit, and 100 unit sizes
(b) Tuberculin syringes
(c) Hypodermic syringes
Parenteral Dosage Forms
(continued)
• Dispensing and administration
pearls
– Needle
• Attached to the tip of a syringe
• Used to draw fluid into the syringe
or push fluid out of the syringe
• The gauge of a needle corresponds
to the size of the lumen (inner core)
• The higher the gauge, the smaller
the needle core
• Diabetic patients use 28 to 32
gauge needles that are short, fine,
or ultrafine.
Remember that the
higher the gauge
number of a needle,
the smaller the
lumen. Conversely,
the lower the gauge
number of a needle,
the larger the lumen.
Parenteral Dosage Forms
(continued)
Insulin vials
Insulin pens
• Multi-dose vial
• Insulin is drawn up into a
special syringe with an
attached needle
• Multiple steps to draw up and
administer
• Portable device
• Insulin is “dialed up”
• More convenient and easier to
transport than vials/syringes
• Do not require purchase of
syringes and needles
• Deliver more accurate dosages
• Easier to use
• Less injection pain
• Retain memory of past
injections
• Disposable
• Disadvantage is cost
Parenteral Dosage Forms
(continued)
• Dispensing and
administration pearls
– Insulin storage
Pharmacy personnel
should inform patients
taking insulin to roll the
medication vials
between their hands to
agitate and warm the
insulin. Insulin vials
should never be shaken.
• Must be protected from
temperature extremes
• Unopened insulin vials or
pens should be refrigerated
• Opened vials or insulin pens
can be stored at room
temperature and discarded
after one month
Parenteral Dosage Forms
(continued)
Route of
administration
Advantages
Disadvantages
Intravenous (IV)
Act rapidly
Inability to retrieve the
medication if an adverse
or allergic reaction
occurs, potential for
introducing microbes or
pyrogens.
Intramuscular (IM)
Convenient,
duration of action
longer than with IV
route, practice for
use outside the
hospital setting.
Onset of response slower
than with IV route,
unpredictable absorption
rate.
In the Know: Fill in the Blank
• When using a _____, it is important to inhale
slowly at the same time it is activated.
metered-dose inhaler (MDI)
• Insulin is administered by the ________ route.
subcutaneous
• Opened vials of insulin may be stored at room
temperature for up to ___________.
one month
Drug Delivery Systems
• A dosage form designed to modify the release
of a drug by one or more pharmacokinetic
parameters (absorption, distribution,
elimination)
• Results in products with improved efficacy and
safety
• Optimizes disease control and patient outcomes
Drug Delivery Systems (continued)
• Delayed-Release
Formulations (DR)
– Have a special coating to delay
absorption of the medication
and to resist breakdown by
gastric acid
– Reduces risk of nausea or
stomach upset
– Enteric coated products
• An example of a delayed-release
formulation
• Coating protects the stomach
• Examples: enteric-coated
aspirin, potassium chloride
Pharmacy technicians
should be aware that
the protective or
timed-release design
characteristics of any
delayed-release or
extended-release oral
formulations would
be compromised if
the medications were
split or crushed.
Drug Delivery Systems (continued)
• Extended-Release Formulation (XL)
– Allow a reduced frequency of dosing as
compared with immediate-release
medications
Pharmacy
technicians should
read drug labels
carefully. A
sustained -release
(SR) dosage form is
not the same as an
extended-release
(XL) dosage form of
the same drug.
– Sustained-release (SR) formulations
• Less frequent dosage schedule
• Example: buproprion SR given 2 to 3
times daily, buproprion immediate
release given 3 to 4 times daily
– Controlled-release (CR) formulations
• At least a twofold reduction in
dosing frequency from the
immediate release or SR product
• Example: Wellbutrin XL given once
daily
Drug Delivery Systems (continued)
• Transdermal patch
– A drug contained within a
patch or disk is absorbed
through the skin.
– A slow-release, steady level
of drug enters the system.
– Absorption is affected by
thickness of the skin and
blood flow, which vary with
age.
– Examples: nicotine,
nitroglycerin, scopolamine
Chapter Summary
• Drugs are administered in many dosage forms.
• The oral route of administration allows medication to
be absorbed through the digestive tract.
• The transmucosal route of administration allows
medication to be absorbed through the mouth, eyes,
ears, nose, rectum, vagina, or urethra.
• The topical route of administration allows medication
to be absorbed through the skin.
• The inhalation route of administration allows
medication to be absorbed through the oral
respiratory route.
Chapter Summary (continued)
• The parenteral route of administration includes the
injection of any drug or fluid into the bloodstream,
muscle, or skin.
• Needles come in various lengths and sizes.
• Insulin is a common medication administered via the
subcutaneous route.
• Drug delivery systems are dosage forms whose
design affects the delivery of the drug.