为什么青霉素不能口服？

青霉素是一种广泛应用于医疗领域的抗生素，它的发现和应用对人类健康产生了巨大的影响。然而，我们可能会好奇为什么这种常见的抗生素不能通过口服途径使用。在本文中，我们将探讨青霉素不能口服的原因。

首先，青霉素不能口服的主要原因是其血液浓度无法维持在治疗水平上。经口给药后，药物将进入胃肠道，并受到胃酸和消化酶的作用。胃酸和消化酶可以破坏青霉素的化学结构，从而降低其活性。此外，口服给药还会导致青霉素在胃肠道内迅速吸收和代谢，使其浓度在血液中无法达到治疗所需的水平。因此，直接口服青霉素无法提供足够的剂量和维持持续的疗效。

Furthermore, another reason why penicillin cannot be taken orally is due to its poor absorption in the gastrointestinal tract. Penicillin is a relatively large molecule and is not easily absorbed through the walls of the stomach and intestines. It requires specific transporters and mechanisms for absorption, which are lacking in the gastrointestinal tract. As a result, even if penicillin is able to survive the harsh environment of the stomach and reach the intestines, it may not be effectively absorbed into the bloodstream, limiting its therapeutic efficacy.

此外，青霉素不能通过口服途径使用的另一个原因是其在胃肠道内吸收较差。青霉素是一个相对较大的分子，不容易通过胃和肠道的壁吸收。它需要特定的转运蛋白和机制来进行吸收，而这些在胃肠道中缺乏。因此，即使青霉素能够在胃的恶劣环境中存活，并到达肠道，它可能也无法有效地通过吸收进入血液中，从而限制了其治疗效果。

Lastly, certain formulations of penicillin, such as penicillin G, can cause severe gastrointestinal side effects when taken orally. These side effects can include nausea, vomiting, diarrhea, and abdominal pain. The gastrointestinal tract is highly sensitive to the presence of penicillin, and oral administration can lead to irritation and inflammation, resulting in these unpleasant side effects. Therefore, penicillin is typically administered through other routes, such as intravenous or intramuscular injection, to avoid these gastrointestinal complications.

最后，某些青霉素的剂型（如青霉素G）在口服时会引起严重的胃肠道副作用。这些副作用包括恶心、呕吐、腹泻和腹痛。胃肠道对青霉素的存在非常敏感，口服给药可能会导致刺激和炎症，从而引起这些不愉快的副作用。因此，为了避免这些胃肠道的并发症，青霉素通常通过其他途径，如静脉或肌肉注射给予。

In conclusion, penicillin cannot be taken orally due to several factors. Its chemical structure is susceptible to degradation by stomach acid and digestive enzymes, preventing it from maintaining therapeutic levels in the bloodstream. Additionally, its poor absorption in the gastrointestinal tract limits its efficacy when taken orally. Lastly, certain formulations of penicillin can cause severe gastrointestinal side effects. Therefore, alternative routes of administration, such as intravenous or intramuscular injection, are preferred to ensure effective treatment with penicillin.

总结起来，由于几个因素的影响，青霉素不能通过口服方式使用。它的化学结构容易受到胃酸和消化酶的降解，无法在血液中维持治疗水平。此外，其在胃肠道内的吸收较差也限制了其口服时的疗效。最后，某些青霉素的剂型可能引起严重的胃肠道副作用。因此，为了确保有效的青霉素治疗，更倾向于选择其他给药途径，如静脉或肌肉注射。

Translation:

Why can't penicillin be taken orally?

Why penicillin cannot be taken orally has always been a question of interest. In this article, we will explore the reasons behind the inability to administer penicillin orally.

Firstly, the primary reason for the inability to take penicillin orally is the inability to maintain therapeutic blood concentrations. After oral administration, the drug enters the gastrointestinal tract and is exposed to gastric acid and digestive enzymes. Gastric acid and digestive enzymes can destroy the chemical structure of penicillin, thereby reducing its activity. Moreover, oral administration also leads to rapid absorption and metabolism of penicillin in the gastrointestinal tract, making it difficult to achieve therapeutic levels in the bloodstream. Therefore, direct oral administration of penicillin cannot provide sufficient dosage and sustained efficacy.

Furthermore, penicillin's poor absorption in the gastrointestinal tract is another reason why it cannot be taken orally. Penicillin is a relatively large molecule and is not easily absorbed through the walls of the stomach and intestines. It requires specific transporters and mechanisms for absorption, which are lacking in the gastrointestinal tract. As a result, even if penicillin is able to survive the harsh environment of the stomach and reach the intestines, it may not be effectively absorbed into the bloodstream, limiting its therapeutic efficacy.

Lastly, certain formulations of penicillin, such as penicillin G, can cause severe gastrointestinal side effects when taken orally. These side effects can include nausea, vomiting, diarrhea, and abdominal pain. The gastrointestinal tract is highly sensitive to the presence of penicillin, and oral administration can lead to irritation and inflammation, resulting in these unpleasant side effects. Therefore, penicillin is typically administered through other routes, such as intravenous or intramuscular injection, to avoid these gastrointestinal complications.

In conclusion, penicillin cannot be taken orally due to several factors. Its chemical structure is susceptible to degradation by stomach acid and digestive enzymes, preventing it from maintaining therapeutic levels in the bloodstream. Additionally, its poor absorption in the gastrointestinal tract limits its efficacy when taken orally. Lastly, certain formulations of penicillin can cause severe gastrointestinal side effects. Therefore, alternative routes of administration, such as intravenous or intramuscular injection, are preferred to ensure effective treatment with penicillin.