Rare ways of administering drugs
intra-arterial, intra-articular, intracardiac, intradermal, intrathecal, via umbilical artery or vein
Elixir
medicine containing active ingredient (such as morphine) dissolved in solution that contains ethyl alcohol and is taken orallly
Tincture
very similar to elixirs, but have higher alcohol percents and must be applied topically
tablet coating purposes
make tablet easier to swallow
enteric coating protects active ingredient from stomach pH and make it only absorbed in certain areas
control rate of release to release it over time
generic drug strength
must have strength between 75 and 125% of brand name drug, but binders in drug can be different so different kinetics may be seen even though strength is similar
infatab
chewable tablet with pediatric dose of medication (ex. phenytoin infatabs prevent epileptic seizures in infants and children)
spansule
capsule with little time-release beads inside
Tembid
long-actin bid formulation of oral nitroglycerin is called Isordil Tembid Tablet, extended release
sublingual
placement below tongue; valuable for patients who don’t want to or can’t swallow
nitroglycerin is most common b/c of heavy 1st pass effect
Some compounds cannot be taken orally b/c stomach acid destroys the active ingredient so sublingiual is good alternative
capsules
2 ends can be pulled apart. Not used much anymore b/c they can be pulled apart and emptied then filled with bad things like guy who put cyanide in tylenol capsules
Some tablets look like capsules but are just compressed tablets
solution
drug in solvent that is equally distributed through liquid; it is homogenized, unlike suspensions where it is not homogenized
common dosage forms
tablets, transdermal patches, inhalers, suppositories, injections, creams, ointments, and lotions
ointments
emulsions that have more oil than water; like vaseline
creams
emuliant system like ointment, but have more water than oil
lotion
emuliant system like cream, but even thinner (more water)
steroid, same drug and strength in cream vs. ointment
will not have same efficacy. Chemical nature of drug may want to separate from ointment. Up to 10-fold difference in potency just by changing dosage form
powders
add water to powder that contains medicine then administer. Many drugs have poor shelf life so this stores them and then can be used when necessary by adding water.
route of administration of a drug follows the pattern of the drug formulation
ex. suppository preparations are only meant to be taken rectally; cannot be used in other ways
some drugs are easier to formulate in any form we want, while others…
can only be made in one form and be effectively administered by that specific route
oral dosage form
oral tablets and liquids are most common, convenient, and safe routes of admin
Disadvantages: relatively slow onset, inactivation by stomach acid, first pass inactivation, interaction with foods and adverse GI side effects
Oral dosage form disadvantages
common GI side effects include nausea, vomiting, diarrhea, and anorexia (loss of appetite)
Liver recieves all portal blood after absorption into SI and has cells with granule enzymes that inactivate and change drugs (ex. nitroglycerin orally never reaches systemic b/c of 1PE; opioids are largely effects too so orally a high dose is needed so some can get through 1PE)
oral tablets
dissolvable solids that usually can be scored down middle so it can be taken in half
solutions
liquids which the mixture of ingredients remains dissolved no matter how long it sits
because of ease of preparation, if active ingredient can be dissolved in water then usually it is made into a solution
caplets
powdered drug or gels suspended inside, but cannot be halved or broken like a capsule
suspensions
liquids containing non-dissolved contents, some of which settle to bottom while on shelf; most antacids are suspensions that must be shaken before use
Elixirs
sweet solutions in which active ingredient is dissolved in water (often with alcohol)
Tinctures
very concentrated alcohol solutions; usually applied to skin
sublingual
not swallowed, just placed under tongue to be absorbed by large BVs found there
only a few drugs can be given this way (most notably NTG)
nasogastric
give through an NG tube; usually liquid drugs and nutrients given this way
drugs are only approved in dosage form they are tested
can’t test a drug in tablet form and get it approved then sell it also as a cream
gastrostomy tube
tube surgically placed directly into stomach or small intestines
rectal suppositories
absorption is very quick and effective. Useful for very young or if they are vomiting.
vaginal cream and suppositories
used for infections and irritations of vaginal tract; most are now OTC but used to be Rx.
Cream intravaginally is no different than oral medicines; both just apply medicine to a mucous membrane (often same cream will be used for mouth and vagina, just rebranded)
topicals
Creams, ointments, eye drops, nasal sprays. Only certain drugs can be give this way; given at one location and it used to treat something in that specific location
Eye drop tips
do not drop the drops near the nose or it will drain faster from the channel that drains the eye that is located on the nose side
trans-dermal
different than topical because it is applied like a topical, but is absorbed trans-dermally and have systemic action, not just at application site. Ex. nicotine patches.
Steady blood levels can be achieved in some medications in patches applied to skin
Transderm Scop
first transdermal medication that came out; scopolamine didn’t work great orally
solutions can be provided by…
ampule: break top part off and draw out contents with a syringe
vile: different top than ampule. Small glass bottle containing liquid or powder. There is a rubber top that the needle can be placed through to absorb the solution
inhalation
very effective way to admin aerosolized liquid medications and very fine powders. Achieves fast response.
Use metered dose inhaler (MDI) or nebulizer (changes liquid medication to mist so can be inhaled).
Second best way to give drugs besides IV, basically any water soluble drug given this way is just as good as IV
Parenteral
anything other than enteral (oral or rectal), but usually means anything by injection
enteral
admin of drug to stomach or intestines
SC
subcutaneous: injection given just under skin, but above muscle layer; there are fewer BVs here so drug is absorbed more slowly
drug expiry date
drug at this point must be within 5% of marketed strength, though some drugs can be used years past this date. Others, like tetracycline or other Rx medications, can turn toxic, but most OTCs are fine after.
IV balloon bags
do not require gravity to drip drugs into systemic circulation b/c balloon shrinking provides force to supply drug into body
Allows patients who need IV to walk around and leave hospital and still have IV delivered
IM
intramuscular: injection directly into muscle which have many BVs so drugs are absorbed quickly
Oral absorption is usually best route of absorption, but if person can’t then IM is usually given (parenterally)
ED drugs
erectile dysfunction drugs used to given by intercavernous (into the corpus cavernosus) injection, but now oral drugs like viagra can be taken which are much less foreboding
IV
intravenous: fastest parenteral injection. Effects are seen almost immediately, which can be dangerous if done incorrectly so only should be done with great care and expertise.
intra-arterial
almost never done; directly into artery
intra-articular
directly into joint
intracardiac
done in movies, but not in real life
intradermal
new influenza done this way; directly into skin
intrathecal
into spinal space; done for spinal anesthesia or for placement of antibiotics for meningitis
via umbilical artery or vein
commonly used in the neonatal ICU b/c after a few hours the opening closes in the newborn and cannot every be used again
just 1 cc of local anesthetic given ___ could make the whole body go to sleep
intrathecal (directly to spinal cavity)
topical admin leads to lowest blood levels unless…
designed for transdermal delivery which requires a special membrane and large drug reservoir
how drug is formulated determines…
how it should be administered. Strongly frowned upon to give medication in dosage form different than specified, but if only option you have to do what you have to do.
Some drugs, like monoclonal antibodies, cannot be given in any method besides one (antibodies must be given by IV or will be destroyed)
universally appropriate drug admin method
there is none. But IV is closest to being universal.
Elixir could not be given if…
patient is taking Antabuse (disulfiram) b/c it inhibits detoxification of alcohol so violent reaction could occur
suppository formulation versus oral
absorbed more quickly and reach higher blood levels, but are hard to find and not as cheap. Plus people don’t like to take them.