The term peroral refers to a form of administration of medications by mouth. Peroral medications are available for a wide variety of ailments in solid, liquid, and semisolid forms. One of the major hazards of this drug administration is the first-pass effect in the liver passage, which may override the active ingredients of the drug.
What is “peroral?”
By the term peroral, pharmacy and medicine refer to drug forms for swallowing. By the term peroral, pharmacy and medicine refer to drug forms for swallowing. Oral administration is one of several forms of internal use. Other internal forms of use include intravenous or rectal administration of a drug. Peroral drugs are either solid or liquid. In liquid form, they are solutions, emulsions, and suspensions. Smaller-dose liquid medications for peroral administration are also called drops or syrups. Solid, peroral medications, on the other hand, are either granules and powders or tablets and capsules. Capsules can be further differentiated into soft gelatin and hard gelatin capsules. The soft gelatin capsules are a rather recent invention, suitable mainly for children. A special form of peroral medications are semisolid drugs. This group includes mainly pastes.
Function, effect and goals
Peroral medications are available for a wide variety of ailments. They do not act locally, but are absorbed by the entire body. In solid peroral drugs, the active ingredient is released either already through the oral mucosa or only in the gastrointestinal tract. If absorption occurs exclusively via the oral mucosa, then these are so-called sublingual drugs. The body absorbs the active ingredients through resorption and spreads them through the bloodstream. Solid forms of peroral drugs have a long shelf life and are also suitable for active ingredients that are not resistant to gastric juice. Capsules with enteric coatings, for example, release the active ingredient only through the alkaline environment of the small intestine. The unpleasant taste of the active ingredients is usually reduced by a solid form. Some of the solid, peroral drugs also provide a delayed constant release of active ingredient, also known as a retard. In this way, the active ingredient is not released all at once, and a sudden increase in blood levels is prevented. In the case of hormones or blood pressure-regulating drugs, for example, this reduces so-called plasma peaks and prolongs the efficacy of the drug. Undesirable side effects are simultaneously reduced by the controlled release of the active ingredients. The main advantage of the peroral liquid form over the solid form is that it is more effective more quickly. Liquid drugs for peroral administration dissolve more quickly and the active ingredients are available more abruptly. The bioavailability of the drug thus increases. Most liquid medications consist of about half sucrose. In this way, sweetness overrides the unpleasant taste of the drugs. Like soft gelatin capsules, this form of drug administration is particularly suitable for children. The peroral form of drug administration is basically one of the simplest and fastest routes of administration. Therefore, the peroral route is particularly well suited for self-administration.
Special features
The peroral route of drug administration must take into account the first-pass effect. This is a metabolization process in the first liver passage. Once the drug has passed through the gastrointestinal tract, its ingredients reach the liver via the portal vein system, where they undergo biochemical transformation. This metabolization can render the active ingredients of the drugs ineffective under certain circumstances. The result of a metabolization process are so-called metabolites. A metabolite can thus in turn correspond to an active ingredient that has become effective or to one that has become ineffective. Many peroral drugs do not in themselves contain a finished active ingredient. An active ingredient is formed from the ingredients only after they have undergone the first-pass effect. This form of peroral drugs is also known as prodrugs. Metabolization is included in these drugs. However, the intensity of the first-pass effect is highly dependent on liver function and to a certain extent individual.Therefore, if an ingredient is expected to be ineffective due to metabolization and no prodrugs are available, another dosage form may be indicated. Peroral drugs that are absorbed through the oral mucosa, for example, can circumvent the first-pass effect. The side effects of a peroral drug depend greatly on the type of active ingredients. Ultimately, however, such drugs without sustained-release properties are associated with a heavy burden on the organism. The active ingredients are released too abruptly with these drugs. In the distant past, peroral medications were associated with an unpleasant to disgusting taste. Today, they are either tasteless or sweetish. Only rarely do patients find the taste unpleasant. However, some people still have problems with taking them perorally. For example, they suffer from a gag reflex when swallowing or, with larger tablets, have the feeling that they cannot swallow at all. In the event of such problems, the doctor may decide to use a different form of administration, such as the rectal form. The choice of a different dosage form may also be indicated for people allergic to lactose, because many peroral medications work with lactose as an excipient. In the past, animal ingredients were also increasingly included as excipients in peroral medications. Today, the medicines are often completely free of animal products and are usually suitable for vegans and vegetarians. Animal testing, on the other hand, is not excluded in pharmaceutical products.
