From the Guidelines
Phentermine is generally not recommended for a 70-year-old patient due to the lack of high-quality data guiding its use in the geriatric population and potential increased risks of cardiovascular side effects. This weight loss medication is typically contraindicated in older adults due to increased risks of cardiovascular side effects, including elevated blood pressure, increased heart rate, and potential heart rhythm disturbances, as noted in the 2022 AGA clinical practice guideline on pharmacological interventions for adults with obesity 1. Older adults are more susceptible to these adverse effects due to age-related changes in cardiovascular function and metabolism. Additionally, phentermine is a sympathomimetic amine with stimulant properties similar to amphetamines, which can cause insomnia, anxiety, and agitation—symptoms that may be particularly problematic in elderly patients.
Key Considerations
- The 2022 guideline mentions that phase 3 clinical trials for phentermine-topiramate ER enrolled subjects up to the age of 70 years, but there are no high-quality data to guide the use of phentermine-based therapies in the geriatric population 1.
- Phentermine should be avoided in patients with a history of cardiovascular disease or uncontrolled hypertension, as well as in those treated with, or within 14 days of, monoamine oxidase inhibitors 1.
- Commonly reported adverse effects of phentermine include constipation, dry mouth, palpitations, insomnia, and irritability 1.
Alternative Approaches
- For weight management in a 70-year-old, safer approaches include dietary modifications and appropriate physical activity.
- Other weight loss medications with better safety profiles in the elderly, such as orlistat or medications like semaglutide that have been studied in older populations, may be considered.
- Any weight loss intervention should be undertaken with close medical supervision in this age group.
From the FDA Drug Label
Geriatric use: Due to substantial renal excretion, use with caution. The FDA drug label does not answer the question.
From the Research
Phentermine Contraindications
- The provided studies do not specifically mention contraindications for phentermine use in 70-year-old individuals 2, 3, 4, 5, 6.
- However, the studies discuss the efficacy and safety of phentermine in various populations, including adults and adolescents, but do not provide information on age-related contraindications 3, 4, 5.
- One study mentions that phentermine is generally well-tolerated in adults, but notes that there is limited research on its long-term use and safety in certain populations 3.
- Another study found that longer-term use of phentermine was associated with greater weight loss and no increased risk of cardiovascular events or death in a cohort of adults with a mean age of 43.5 years 5.
Age-Related Considerations
- None of the provided studies specifically address the use of phentermine in individuals aged 70 or older.
- The studies focus on the efficacy and safety of phentermine in younger populations, including adults and adolescents 2, 3, 4, 5, 6.
- As a result, there is limited evidence to inform the use of phentermine in older adults, and clinicians may need to consider other factors, such as comorbidities and medication interactions, when prescribing phentermine to this population.