Introduction
With obesity rates continuing to climb in the United States, many people are looking for ways to lose weight. Two of the most popular weight loss medications currently on the market are phentermine and Mounjaro. Phentermine is an appetite suppressant that has been around for decades, while Mounjaro is a newer injectable diabetes medication that was recently approved for weight loss. This has led many to wonder - can you take phentermine and Mounjaro together?
What is Phentermine?
Phentermine is a stimulant medication that suppresses appetite. It works by influencing the central nervous system to decrease hunger. Phentermine was approved by the FDA in 1959 as a short-term weight loss medication to be used along with diet and exercise. It is sold under brand names like Adipex-P, Lomaira, and Suprenza.
Phentermine is only approved for short-term use of 12 weeks or less. This is because it can lead to tolerance where it becomes less effective over time. Phentermine is also a controlled substance due to its potential for abuse and dependence. For these reasons, phentermine use needs to be closely monitored by a healthcare provider.
How Phentermine Works
Phentermine works by stimulating the release of norepinephrine and dopamine in the brain. This triggers a fight-or-flight response, which suppresses appetite. Some of the other effects of phentermine include:
- Reduced hunger and cravings
- Increased energy and focus
- Faster metabolism
- Improved mood
Phentermine causes the release of catecholamines like norepinephrine into the hypothalamus region of the brain which is responsible for controlling hunger and satiety. This leads to reduced food intake by signaling the body it is full.
Who is Phentermine For?
Phentermine is approved by the FDA for use in adults with obesity defined as having a BMI of 30 or higher. It may also be prescribed to those with a BMI of 27 or higher who also have obesity-related conditions like hypertension, diabetes, or dyslipidemia.
Phentermine is not intended for use in children under the age of 16. It has also not been studied in older adults. Phentermine is not recommended for people with a history of heart disease, stroke, uncontrolled high blood pressure, hyperthyroidism, glaucoma, or serious psychiatric conditions.
Risks and Side Effects
As a stimulant, phentermine can cause side effects like:
- Increased heart rate and blood pressure
- Insomnia
- Dry mouth
- Constipation
- Headache
- Nervousness or restlessness
- Irritability
More serious risks associated with phentermine include heart valve problems, pulmonary hypertension, and abuse or dependence. Phentermine should not be taken with other stimulants due to the risk of dangerous effects on the cardiovascular system.
What is Mounjaro?
Mounjaro is a brand name for tirzepatide, a new glucose-lowering injectable medication developed by Eli Lilly and approved by the FDA in 2022. While it was initially approved as a treatment for type 2 diabetes, it was also recently approved for chronic weight management in adults with obesity or who are overweight.
How Mounjaro Works
Mounjaro is a GLP-1 receptor agonist. It mimics the effects of GLP-1, an appetite-regulating hormone produced in the intestines. Mounjaro activates GLP-1 receptors which leads to several effects:
- Slows digestion and reduces food intake
- Increases insulin production
- Lowers blood sugar
- Suppresses appetite
Mounjaro improves blood sugar control while also promoting weight loss through reduced hunger and calorie intake. The effects of Mounjaro on weight are believed to be due to higher doses providing stronger activation of GLP-1 receptors.
Who is Mounjaro For?
Mounjaro was initially approved as an adjunct treatment for type 2 diabetes in adults. For chronic weight management, it is approved for use in adults who are either:
- Overweight or obese (BMI of 27 or higher)
- Overweight (BMI of 25 or higher) and have at least one weight-related medical condition like hypertension, type 2 diabetes, or high cholesterol
Mounjaro has not been studied and is not approved for use in pediatric patients under 18 years old.
Risks and Side Effects
Possible side effects of Mounjaro include:
- Nausea, vomiting, diarrhea
- Indigestion
- Decreased appetite
- Dizziness
- Fatigue
- Abdominal pain
- Constipation
- Headache
Mounjaro may also increase the risk of pancreatitis and thyroid tumors. It is not recommended for use in patients with a personal or family history of medullary thyroid carcinoma or those with Multiple Endocrine Neoplasia syndrome type 2.
Can You Take Phentermine and Mounjaro Together?
There is no direct interaction between phentermine and Mounjaro. However, some medical experts recommend avoiding using these two medications together due to overlapping effects on appetite and potential risks.
Overlapping Effects on Appetite
One of the main concerns with using phentermine and Mounjaro concurrently is that both medications suppress appetite and food intake. Phentermine reduces hunger by increasing neurotransmitters like norepinephrine while Mounjaro mimics hormones that regulate appetite.
When combined, these effects may be compounded, leading to excessive appetite suppression. This could potentially increase the risk of nutritional deficiencies. More research is still needed on any synergistic impacts on appetite and weight loss.
Cardiovascular Risks
As a stimulant, phentermine already carries risks like elevated heart rate and blood pressure. Mounjaro may also increase heart rate, though likely not to the same extent. Combining the two could potentially increase cardiovascular side effects.
Those with a history of heart disease or stroke may be at higher risk for complications like increased strain on the heart. For this reason, some experts recommend against using phentermine and Mounjaro together if you have pre-existing heart issues.
Other Safety Concerns
In addition to effects on appetite and the cardiovascular system, some other general safety considerations about using phentermine and Mounjaro together include:
- Lack of research on interactions or contraindications
- Potential for increased side effects
- Uncertain effects on blood pressure
- May lower seizure threshold
- Likelihood of diminishing returns over time
The risks versus benefits of combining these two medications are still unclear. Using them together may lead to enhanced weight loss initially but also increase the potential for adverse effects with long-term use.
The Bottom Line
At this time, there are no formal recommendations against taking phentermine and Mounjaro concurrently. However, the general recommendation is to avoid combining the two due to uncertainties about safety and effectiveness.
While using phentermine and Mounjaro together could potentially amplify appetite suppression and weight loss, there are outstanding concerns about effects on cardiovascular health. There is
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.
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