What is the most common side effect of phentermine?

Phentermine is a stimulant medication commonly prescribed for weight management. The most prevalent side effect associated with its use is xerostomia, which is the medical term for dry mouth. This occurs because phentermine can reduce saliva production, leading to a feeling of dryness in the mouth.

Xerostomia can be quite noticeable for patients and may lead to difficulties in speaking, swallowing, and an increased risk of dental issues due to a lack of saliva that helps protect the teeth and gums. It is important for patients to be aware of this side effect, as it may prompt them to increase their fluid intake or take proactive measures to manage dry mouth.

Other side effects such as weight gain, diarrhea, or excessive sweating are less commonly reported with phentermine. Weight gain is contrary to the purpose of prescribing phentermine as a weight-loss aid, while diarrhea and excessive sweating are not typical side effects linked to its mechanism of action. Understanding the primary side effect of xerostomia can help healthcare providers better counsel their patients on what to expect when they start this medication.