Meridia vs. Phentermine: Differences, Safety, Side Effects and Availability

Availability and approved use

The FDA says sibutramine was withdrawn from the U.S. market in December 2010 after clinical data indicated an increased risk of heart attack and stroke. Products claiming to contain Meridia or sibutramine should be discussed with a healthcare professional; do not assume an online listing is legitimate or approved.

Current U.S. phentermine labeling describes it as a short-term adjunct—alongside reduced-calorie eating, exercise, and behavior changes—for certain people with obesity. It is a controlled prescription medicine and is not appropriate for everyone.

Risks and side effects

FDA information links sibutramine with increased cardiovascular risk, including heart attack and stroke, and notes it can raise blood pressure or pulse in some people. Its U.S. withdrawal is a major safety difference, not merely a difference in brand availability.

Phentermine can affect the cardiovascular and nervous systems. Its label lists contraindications that include cardiovascular disease, uncontrolled hypertension, hyperthyroidism, glaucoma, agitated states, and certain medication interactions. A prescriber must review a person’s history and medicines.

Do not substitute or source these medicines online

Do not use sibutramine, products marketed as Meridia, or phentermine without a current prescription and clinician oversight. Ask a licensed healthcare professional about safe, currently available approaches to weight management that fit your health needs.

Sources

• FDA: Sibutramine (Meridia) and associated risks
• DailyMed: phentermine prescribing information