Final answer:
The most common adverse reaction to penicillin is an allergic reaction, which can range from mild to severe. Monitoring the patient post injection is critical as allergic reactions can be life-threatening. Other side effects like diarrhea are also possible but are not the primary immediate concern following an injection.
Step-by-step explanation:
The most common adverse reaction to penicillin is an allergic reaction. This type of hypersensitivity can vary in severity, with some patients experiencing mild allergic responses, while others might have more severe reactions, such as anaphylaxis. Sarah is monitoring the patient for 30 minutes post injection as a precautionary measure, which is a common practice in medical settings when administering substances that could potentially trigger an allergic reaction. This monitoring is essential because allergic reactions can be life-threatening, requiring immediate medical intervention.
While diarrhea can also be a side effect of antibiotic treatment due to the disruption of the balance of good and bad bacteria in the gut, it is generally not as immediately dangerous as an allergic reaction. The antibiotics can sometimes lead to conditions like a yeast infection or digestive distress as well, because they can kill beneficial bacteria as well as the harmful ones they are intended to eliminate. However, these types of side effects are typically not the primary concern immediately following the administration of a penicillin injection.
Additionally, it is important to note that if patients are known to be allergic to penicillin, alternative antibiotic treatments are available. These other antibiotics may require careful monitoring and retesting to ensure effectiveness, especially in the treatment of infections like syphilis.