Suppositories Lecture Flashcards
Define suppositories
Solid or semisolid dosage form intended for insertion into the body orifices where it melts, softens, or dissolves and exerts localized or systemic effects
What are the three types of suppositories?
Rectal, vaginal, urethral
What are the local action uses of suppositories?
Enables high local concentration
Faster onset of action
Relieve constipation, irritation, itching, inflammation, contraception, local anesthetics
What are the systemic action uses of suppositories?
Absorbed from mucous membranes of rectum and vagina
Avoids the first pass effect
Absorption is erratic and unpredictable
What are common suppositories for anti-hemorrhoidal suppositories?
Local anesthetics (benzocaine, lidocaine, pramoxine HCl)
Vasoconstrictors (epinephrine HCl, ephedrine sulfate, phenylephrine Hcl)
Astrigents (calamine, zinc oxide)
Soothing and protecting agent (lanolin–> physical barrier)
What are common suppositories for laxatives suppositories?
Glycerin suppositories (causes laxative action local irritation of the mucous membrane) Hyperosmotic laxative (draws water from surrounding tissue to the bowel)
Suppository for asthma?
Aminophylline
Suppository for NSAID?
Indomethacin
Suppository for nausea, tranqulizer?
Prochlorperazine
Suppository for nausea and vomiting?
ondansetron
Suppository for hypnotic?
chloral hydrate
Suppository for narcotic analgestic?
Oxymorphone HCl
Suppository for analgestic, antipyretic?
Asprin
Suppository for analgesic
Acetaminophen
What are advantages of suppositories?
Avoidance of oral and parenteral routes (protect drugs destroyed by the pH or enzymes of the stomach)
Patient who cant swallow
Unconscious patients
Heavy vomiting patients
Target delivery (minimized systemic toxicity, concentrated drug at the site of action)
What are the disadvantages of suppositories?
Messy to apply
Variation of absorption (colonic content, pH, placement to high, GI probs)
Irritation for mucous caused by drugs or bases
Leak or expelled after insertion
Cultural and religious factor
What are suppository characteristics?
Shape and size: vary to promote insertion and facilitate retention
Must release medicament: melt at body temp, dissolve (must absorb moisture and dissolve)
How do rectum suppositories absorb?
Melting or liquifaction
Must diffuse across the water and mucous layers adjacent to the epithelium
Drug delivered to the upper part of the rectum to be transported into the portal system
Avoid first pass: lower part of the rectum delivery
Rectum supp absorption depends on?
Physiological factors
Physiochemical nature of drug and its ability to traverse the physiologic barriers to absorption
Nature of the suppository base and its ability to release drugs
What physiological factors that affect drug absorption from the rectum?
Colonic content
Blood circulation
pH and lack of buffering capacity of the rectal fluids
What is colonic content?
When the rectum is void»_space;> full of fecal matter
Conditions such as diarrhea, colonic obstruction due to tumor or tissue dehydration
What does blood circulation mean?
Lower hemorhoidal vein of the colon receives teh absorbed drug and initiates its circulation throughout the body and thus bypasses the liver
Lymphatic circulation also assists
Any obstruction to blood supply to the rectum will affect the drug absorption from the rectum
What does rectal fluid have to do with absorption?
Do not generally undergo ionization because rectal fluid is essentially neutral in nature and have no buffer cpacity
Rectal pH may vary
Cocoa butter is immiscible with rectal fluid (retards the release of fat soluble)
Max bioavailability, use ionized form (salt), rather than unionized form.
What are the effects of solubility?
Lipophilic drugs
- slow release in oily base
- moderate release in water soluble/miscible base (drug dissolves slowly in aqueous compartment)
Water soluble drugs
- rapid release in oily base
- rapid to slow release in water soluble/miscible base
