Wegovy and Phentermine: Is It Safe? Label, Studies
Avoid unless your prescriber plans it: the phentermine label does not recommend combining weight loss drugs.
- Verdict
- Avoid together
- Label names it
- No
- General caution
- Pills absorbed more slowly
Check a GLP-1 interaction
Wegovy in brief
Its half-life is about 1 week: after 7 d, half is gone, and after five half-lives (35 d), about 3% remains.
STEP 1 reported 14.9% of body weight at 68 weeks, compared with 2.4% on placebo.
Prices each month in US dollars cover the list price and self-pay offers. The maker's price page gives each amount.
Sources: FDA label (DailyMed), healthsystemtracker.org, prnewswire.com 1 2.
Wegovy and phentermine: the verdict
Avoid together
The Wegovy label’s drug interactions section says this word for word:
“WEGOVY causes a delay of gastric emptying and thereby has the potential to impact the absorption of concomitantly administered oral medications. In clinical pharmacology trials”
Source: FDA DailyMed label.
What the label for Wegovy says
The Wegovy label does not mention Phentermine. These lines still apply to it.
| Named in the label | The risk | What the label tells doctors |
|---|---|---|
| Oral medicines | Pills absorbed differently | Slowing stomach emptying with it can affect how other pills are absorbed. |
Source: Wegovy label (DailyMed).
What the studies show
- Label limitation: the combination has not been established
- Label limitation: it is not recommended
- Label interaction with oral medicines
Source: FDA DailyMed label.
The practical rule
- Do not add Phentermine on your own. Combine the two only if your prescriber plans to do so and closely follows your care.
- Tell the person who prescribes your GLP-1 about every pill you take, including this one.
- Check with your pharmacist whether you need a steady blood level for any pills you take. When you start or raise the dose, these may need to be checked.
Source: FDA DailyMed label.
Phentermine with other GLP-1s
Not one of the 10 GLP-1 labels mentions Phentermine in its drug interaction section. All labels repeat the same general warning about pills you swallow, so the answer remains the same throughout the class.
For Rybelsus, Mounjaro, the same question also applies.
Source: FDA DailyMed label.