Suppositories have a local effect or a systemic effect (an effect on the entire
body), depending upon the active ingredients in the suppository.
a. Local. Frequently, a local action is desirable for a rectal or vaginal
inflammation or condition. In such cases, the local action of an emollient, local
anesthetic, astringent, analgesic, or antibiotic is sought. Drugs that are not absorbed
from the site to which they are introduced can exert only a local effect. Those that are
absorbed may exert both a local and a systemic action. The concentration of the agent
will have a bearing upon the systemic action, if the drug is absorbable.
b. Systemic. The systemic actions for which suppositories are used are limited
only by the drug's solubility and absorbability. Thus, it is possible to administer
antiemetics, antibiotics, analgesics, antipyretics, muscle relaxants, sedatives, hypnotics,
and so on, in the form of suppositories.
USES OF SUPPOSITORIES
Suppositories are often used when the patient is unable to swallow medications.
For example, a patient who is vomiting would probably be unable to swallow (and
retain) a tablet or capsule. Suppositories can be used as vehicles for antiemetics
(drugs which prevent nausea and vomiting) and sedatives. Further, suppositories can
be used as vehicles to carry drugs that irritate or upset the stomach.
Extensive testing and research have shown that, because of many variables,
there is no accurate relationship of rectal to oral dose. That is, it cannot be said that
half, twice, or four times the oral dose is necessary to elicit the same response rectally.
In practice, however, the rectal dose prescribed is normally in the range between one-
half and twice the oral dose. Factors entering this variable dose are: the nature of the
base used, rapidity of release of the active principles, the nature of the active
medication, and the solubility and absorbability of the drug. The inability to accurately
calculate a rectal dose for medication is probably the biggest reason that more and
more drugs are not routinely given by the rectal route.
5-10. SUPPOSITORY CASES
a. Theobroma Oil. Theobroma oil (cocoa butter) is a yellowish-white, greasy-
to-the-touch, nonirritating, emollient substance with the characteristic odor of chocolate.
It is solid at room temperature and begins to liquefy at about 30C (94 Fahrenheit (F)).
Thus, at body temperature (37C/98.6 F), theobroma oil is a liquid.