From the Research
Phentermine has not been definitively linked to interstitial lung disease (ILD). While phentermine is a sympathomimetic amine used for short-term weight loss in obese patients, there is currently no substantial evidence in medical literature establishing a causal relationship between phentermine use and the development of ILD 1. The most common side effects of phentermine include increased heart rate, elevated blood pressure, insomnia, dry mouth, constipation, and nervousness, which are related to its stimulant properties.
Pulmonary complications from phentermine are rare, though there have been historical concerns about pulmonary hypertension when phentermine was used in combination with fenfluramine (fen-phen), which was withdrawn from the market in 1997 2. However, this association is not directly related to ILD. If a patient taking phentermine develops unexplained respiratory symptoms such as progressive shortness of breath, persistent cough, or decreased exercise tolerance, they should seek immediate medical attention as these could indicate a serious pulmonary condition requiring evaluation, regardless of whether it's related to medication use.
Some studies discuss the diagnosis and management of ILD, including the use of high-resolution computed tomography (HRCT) and pulmonary function tests (PFT) 3, 4. However, these studies do not establish a link between phentermine and ILD. Another study discusses drug-induced interstitial lung disease (DILD), but does not mention phentermine as a causative agent 5.
In summary, based on the current evidence, there is no definitive link between phentermine and ILD, and patients taking phentermine should be monitored for any respiratory symptoms, but the medication itself is not a known cause of ILD 1.