Suppositories

Definition of suppositories

Normally, when we hear of "suppositories" we immediately refer to pharmacological preparations to be administered rectally; in reality, the term "suppository" is more general and, besides indicating this precise route of administration, it also refers to the application of the drug directly in the vagina (vaginal ovules) or in the urethra (urethral suppository).

Supporters in general, and suppositories in particular, are solid pharmaceutical forms containing an active ingredient dissolved in a fat or otherwise waxy medium; the particular composition of the excipients allows the drug to liquefy, therefore to be released and to spread after a very short period of time from insertion into the rectum, vagina or urethra.

The suppositories exercise their therapeutic action both locally and systemically: to report some examples, the suppositories formulated with glycerin act at the local level favoring evacuation in a short time, while those prepared with paracetamol or with anti-inflammatory drugs can be administered at rectal level to lower fever or to lighten headaches and other types of pain.

Active ingredients and types

The active principle that composes the suppositories is chosen according to the disorder to which it is desired to remedy; the drug is always formulated in association with excipients, useful for containing the active ingredient, favoring its fusion in contact with the heat of the body, and forging the suppository.

The peculiarity of the suppositories lies precisely in the peculiar solid composition: introduced into the organism (in the rectum, in the vagina or in the urethra) in solid form, the suppository dissolves rapidly and, subsequently, is absorbed due to the blood vessels.

Some suppositories are formulated with an oleaginous base, such as cocoa butter, in which the active ingredient is dissolved; other suppositories - especially those for vaginal and urethral use - consist of propylene glycol, a water-soluble (water-soluble) excipient. The glycerine suppositories are instead composed of glycerol and gelatin, and are normally used for laxative purposes.

There are also the so-called liquid suppositories, in which the administration of the drug (generally a laxative) is carried out through a special syringe, directly into the rectum.

Rectal suppositories

RECTAL SUPPOSITORIES can determine their own therapeutic action at the local or systemic level:

1. At the local level, the suppositories are formulated with drugs capable of facilitating evacuation: the laxative active ingredients - generally emollients - which compose them, acting directly at the level of the anal mucosa, induce evacuation through a lubrication of the rectum. These supporters are normally formulated with a glycerine base. Still, at a local level, suppositories can be formulated with active ingredients capable of exerting a beneficial action for the treatment of hemorrhoids : in this case, rectal suppositories are formulated with substances with a vasoconstrictor action.
2. At the systemic level, suppositories can be used for various purposes: in this case, it is recommended to introduce the suppository after evacuation, to prevent it from being expelled before being absorbed by the body. To act systemically, the active ingredient with which the rectal suppository is formulated is rapidly absorbed by the mucosa of the rectum which, as we have observed, is rich in blood vessels: after the drug has reached the circulation, it can reach the target organs. The active ingredients most used to prepare rectal suppositories of this type are: paracetamol (to lower fever), promethazine (for the treatment of nausea and vomiting), acetylsalicylic acid and opiates (to reduce pain), etc.

Vaginal suppositories

The VAGINAL SUPPOSITORIES include a series of pharmacological preparations for purely gynecological use: among vaginal suppositories, we mention: vaginal ovules, vaginal tablets and creams to be applied internally through a special cannula.

Even this category of drugs can exert its therapeutic effect at a local and systemic level: some vaginal suppositories are formulated with a mixture of lactobacilli, useful for ensuring the balance of the vaginal bacterial flora; others are composed of antibiotics (for example, to eradicate bacterial infections, sustained by Trichomonas vaginalis, Mycoplasma hominis, Neisseria gonorrhoeae, etc.), antifungals (for the treatment of Candida albicans infections) and antiviral (to treat virus infections, like those supported by Herpes simplex ).

Urethral suppositories

URETHRAL SUPPOSITORIES are indicated for treating male disorders, including erectile dysfunction and impotence; in the United States, the commercial name of these particular supporters is MUSE, an acronym for Medical Urethral System for Erection. These particular pharmacological formulations are modular transurethral devices, in which the drug is introduced into the urethra using the special "piston" applicator.

Rectal suppositories: Advantages and disadvantages

Many doctors advise taking a certain drug rectally, in the form of a suppository: the advantages derived from this route of administration are in fact remarkable; however, the disadvantages are not lacking. But let's see them in more detail.

ADVANTAGES

Unlike drugs administered orally, suppositories taken rectally do not cause gastric irritation, since they do not pass through the stomach.

Another important advantage, which differentiates rectal suppositories from oral tablets, concerns enzymes: drugs that would be inactivated by gastric enzymes remain so when applied rectally.

In the case of vomiting, even after taking a rectal suppository, the characteristic problem of oral drugs does not arise: as we know, when it occurs before the active ingredient has been completely absorbed by the body, vomiting can compromise the effectiveness of the drug . For rectal suppositories, this problem does not exist.

Suppositories are particularly indicated following gastrointestinal surgery, as well as in children and the elderly who struggle to swallow medicines by mouth.

DISADVANTAGES

If up to this point we have analyzed the suppositories as an exceptional modality of pharmaceutical administration, we must not forget the possible disadvantages.

Although the rectal mucosa is rather rich in blood vessels, the suppository is placed in contact with a markedly reduced area of ​​absorption compared to the intestinal one; consequently, the absorption of the drug by the rectal route is reduced if compared to that of oral medicines. Furthermore, the absorption of the drug formulated in the form of suppositories, as well as its availability, is neither constant nor predictable: depending on the point at which the active ingredient arrives, it can be absorbed by the lower hemorrhoidal plexus, or by the middle or upper: for this reason, the drug may or may not pass through the liver.

The area in which the rectal suppository exerts its action is subject to irritation; not surprisingly, many suppositories are formulated with laxative active ingredients, which favor evacuation by exerting a mild irritation of the anal mucosa.

Another important element should not be underestimated: the bacteria that colonize the anus and the rectum can sometimes inactivate part of the active principle, thus reducing the activity of the drug.

The key concepts described above are summarized in the table

Advantages of suppositories by rectal route	Disadvantages of the suppositories by rectal route
They do not cause gastric irritation The drug is not inactivated by gastric enzymes The drug is also absorbed in case of vomiting The laxative effect of some drugs formulated as suppositories is almost immediate Indicated for those who complain about difficulty swallowing tablets orally and for those who have undergone gastrointestinal surgery	Rectal area: less absorption than the intestine Not constant and unpredictable drug absorption Area prone to irritation Possible inactivation of the drug by bacteria Drug absorption quite slow

Entry mode

To obtain maximum therapeutic efficacy, the correct insertion of the suppository is very important; below are the general guidelines for correctly assuming a rectal suppository.

1. Wash your hands thoroughly.
2. If the suppository is soft, it is advisable to place it in the refrigerator for a few minutes, or to leave it in cold water (before opening the package) to allow the excipients to solidify the suppository.
3. Remove the casing cover.
4. If necessary, cut the suppository with a soft cloth (based on the dosage prescribed by the doctor).
5. Wear a latex glove if necessary.
6. It is advisable to lubricate the upper part of the suppository, to facilitate its insertion into the rectum.
7. Lie down on one side, with the leg resting on the floor lying flat, the other slightly bent forward, towards the abdomen.
8. Lift a buttock and insert the suppository into the rectum, so that it goes beyond the anal muscle sphincter.
9. It is advisable to maintain the lying position on your side for a few minutes to prevent the suppository from being expelled.
10. Wash your hands thoroughly.