*An off-label use of a medication is a use that is not FDA-approved. Prescribers can decide to use a medication off-label because, in their professional judgment, they believe it may offer a benefit to someone.
*An off-label use of a medication is a use that is not FDA-approved. Prescribers can decide to use a medication off-label because, in their professional judgment, they believe it may offer a benefit to someone.
Phentermine (branded version Adipex-P) is a medication used to help people lose weight vs Adderall (amphetamine/dextroamphetamine) is used for attention-deficit/hyperactivity disorder (ADHD). They share similarities because they may cause weight loss, but Adderall is only approved for ADHD. Also, Adderall carries different warnings and side effects from phentermine, such as psychological effects, while phentermine mostly causes heart-related effects.
If you’re considering phentermine or Adderall, or want to discuss your current prescription with a provider, you will be limited in your options. Circle Medical is an online psychiatry platform that can and will prescribe stimulant medications, which are controlled substances. This platform can connect you with a provider quickly and offer assessments and prescription consultation.
Boxed Warning: Amphetamine, dextroamphetamine mixed salts (Adderall) - Risk of medication misuse or abuse
Adderall has a black box warning. These are the most serious types of warnings from the Food and Drug Administration (FDA). Amphetamines, an active ingredient in Adderall, have a risk of misuse (abuse) which can lead to dependence on the medication, serious heart conditions, and even sudden death.
Adderall is a controlled substance, which means that it’s more likely to be misused or cause dependence. There are federal and state laws that limit the amount of medication that can be prescribed or dispensed within a certain period of time.
Phentermine is a controlled substance, which means that it’s more likely to be misused or cause dependence. There are federal and state laws that limit the amount of medication that can be prescribed or dispensed within a certain period of time.
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What Is Phentermine?
Phentermine is FDA approved to help people who are diagnosed with obesity to lose weight and is used in combination with lifestyle changes. A drug that is FDA-approved means it has been accepted by the FDA as safe and effective for a specific use based on data from clinical trials. Phentermine works as an anorectin that works on the brain to raise blood pressure and decrease appetite.
How Does Phentermine Work?
Phentermine works to reduce appetite in people with obesity and should only be used for a few weeks. When it takes action, a stress response is triggered that activates norepinephrine and epinephrine, leading to a decrease in appetite. Phentermine is only approved for use if you can combine it with physical activity, behavioral changes, and caloric restriction.
What Is Adderall?
Adderall, with the active ingredients amphetamine and dextroamphetamine, is FDA-approved to treat ADHD in people 3 years and older. It is a part of the amphetamine drug class and can be used off-label to treat depression, bipolar depression, narcolepsy, and for promoting weight loss. Since it may influence hormones that affect mood, Adderall may help with depression symptoms for some people. Adderall may also have an effect on personality for some people. Adderall also works by increasing hormones that can affect stress, which may lead to decreased appetite.
How Does Adderall Work?
Adderall works by increasing the hormones norepinephrine and dopamine in the brain, which increase energy and may improve mood, as well as many other effects. Some people who have ADHD may have a deficit in these chemicals, and that may contribute to symptoms such as difficulty focusing and hyperactivity. These symptoms may negatively affect grades in school, social relationships, and may contribute to other mental health issues.
How Are Phentermine & Adderall Similar?
Phentermine and Adderall are both stimulants and may provide a feeling of increased energy. Both may lead to increased blood pressure and serious heart conditions. Also, they may both be used for ADHD and weight loss. Both have a potential for abuse and misuse and should be carefully monitored. Adderall and phentermine have similar side effects, such as restlessness and increased heart rate.
Key Differences Between Phentermine & Adderall
The differences between phentermine and Adderall include the way they work, the ages approved, and their warnings. Adderall works on dopamine and norepinephrine, while phentermine works on norepinephrine and epinephrine. They both have warnings about potentially harmful effects, and most of the side effects are the same. Adderall may cause psychological symptoms, while phentermine is more often associated with an increased risk of heart conditions.
Here are the key differences between phentermine versus Adderall:1, 2
| Key Components | Phentermine | Adderall |
| What is the generic name? | phentermine | amphetamines- dextroamphetamines |
| What is the active ingredient? | phentermine | amphetamines- dextroamphetamines |
| What forms does it come in? | Tablets and capsules | Tablets |
| What are the typical dosages? | 37.5 milligrams (mg) | 5 mg, 7.5 mg, 10 mg, 15 mg, 20 mg, and 30 mg |
| Who is approved to take it? | Adults 18 years and older | Children 3 and older, teens 12-17, and adults 18 and older |
| What are the different warnings? | Psychosis, long-term suppression of growth in children, seizures, Renaud’s, serotonin syndrome, and worsened Tourette syndrome | Taking with other weight loss drugs, potential harmful behavior, and use with diabetes medications |
Can Phentermine Help ADHD Symptoms?
Phentermine is not approved for treating ADHD but some prescribers may choose it as an off-label treatment option for a patient. However, there are no clinical trials proving phentermine works for ADHD. There are only reports of such cases.
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Can Adderall Be Used for Weight Loss?
Adderall should not be used for weight loss. It is only approved for ADHD and has a high abuse potential. Adderall may result in weight loss of about 5 pounds, while phentermine results in about a 5% reduction in body weight.3, 4
Phentermine Vs Adderall Dosages
Adderall comes as tablets, while phentermine comes in the form of tablets and capsules. The right form or dosage for an individual is determined by the disorder being treated, your age, and other factors. Doses can vary for each person and are not standardized for off-label uses.
Phentermine Form & Dosages
Phentermine comes as a tablet or capsule. It is only available at 37.5 mg for either form. It is a controlled medication that has abuse potential. Phentermine comes as a small white tablet with blue freckles or a blue and white capsule. The tablets are immediate-release, while capsules are extended-release.
Adderall Form & Dosages
Adderall is also available as a tablet. If you need a different form, such as a liquid, there are other available forms of Adderall. Adderall is also a controlled substance and has a high abuse potential. The doses Adderall comes in include 5 mg, 7.5 mg, 10 mg, 15 mg, 20 mg, and 30 mg. Adderall comes in many different colors, depending on the dose.
Side Effects of Phentermine Vs. Adderall
Phentermine and Adderall have many side effects in common, but also several defining differences. For example, do not take phentermine if you have glaucoma or hyperthyroidism. Adderall should not be taken if Tourette syndrome, Raynaud’s phenomenon, or seizures. Commonly experienced side effects are often mild, though some may require medical attention.
Common side effects from taking phentermine may include:*1
- Dizziness
- Headache
- Restlessness or insomnia
- Stomach or intestinal problems, diarrhea, or constipation
- Dry mouth
Serious side effects from taking phentermine may include:*1
- Abuse, overdose, or dependence
- Cause or worsen heart conditions, including heart attack, stroke, or sudden death
- Chronic intoxication
Common side effects from taking Adderall may include:*2
- Increased heart rate or blood pressure
- Restlessness
- Stomach or intestinal issues
- Blurry vision or pupil dilation
- Rash
- Changes in sex drive
Serious side effects from taking Adderall may include:*2
- Heart disease, heart attack, and sudden death
- Stomach or intestinal death
- Psychosis
- Serious and potentially fatal rash
- Potentially fatal kidney disease
*All medications, including Adderall and phentermine, have a risk of side effects, including serious side effects. This is not a complete list of side effects. You should talk with your healthcare professional about the benefits and risks of any medication before starting treatment.
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Warnings & Precautions for Adderall & Phentermine
Phentermine and Adderall have some serious side effects that should be considered before use. Like all medications, they have a risk of severe allergic reactions. Both have abuse and overdose potential can occur and be fatal. In addition, both medications can cause severe heart conditions or harmful increase in blood pressure. They also can have serious side effects if taken with alcohol.
Risks to consider when taking phentermine include:1
- Allergic reactions: If an allergic reaction occurs when taking phentermine, get immediate medical help. The reaction is rare but may include symptoms of difficulty breathing, hives, and increased heart rate or palpitations.
- People with uncontrolled high blood pressure: Since phentermine raises the chemicals that increase blood pressure, do not take phentermine if your blood pressure is uncontrolled.
- Risk of abuse, misuse, addiction, overdose, and dependence: Phentermine is chemically related to other amphetamines that have been abused.
- High blood pressure in the lungs: A rare but fatal side effect of phentermine includes high lung blood pressure if combined with other weight loss drugs.
- Disease of the heart valves: Combining phentermine with other weight loss drugs has led to serious heart disease in otherwise healthy people.
- Development of a tolerance to phentermine: If a tolerance is developed, instead of raising the dose, phentermine should be discontinued under medical guidance and supervision.
- Potential to engage in harmful activity: Phentermine can increase the urge to do activities like impulsive shopping and cause more impulsive or unclear thinking.
- Use with alcohol: Phentermine is a stimulant, while alcohol is a depressant. Using both together may cause serious side effects.
- People with diabetes: Medications, including insulin, can lower blood glucose, while phentermine lowers appetite.
- High lung blood pressure: The development of high blood pressure in the lungs is a potential serious side effect of phentermine. Symptoms include difficulty breathing, chest pain, fainting, or lower leg swelling.
- Heart disease: Heart attacks and strokes have also occurred while taking phentermine. Symptoms include rapid heart rate and increased blood pressure.
- Chronic intoxication: Phentermine should only be taken for a maximum of a few weeks.
Risks to consider when taking Adderall include:2
- Allergic reactions: Adderall may cause a rare but serious allergic reaction and requires immediate medical care. Hives, shortness of breath, and fainting can occur.
- Risk of addiction or misuse: Since Adderall increases “feel-good hormones,” it is a common drug of abuse and can cause addiction. Adderall withdrawal may also occur for some people.
- People with heart conditions: Adderall can cause high blood pressure, heart attacks, strokes, or death of heart tissue. Do not take Adderall without your doctor’s orders.
- Onset or worsened psychosis: Due to the chemical changes Adderall may promote, there may be a higher risk of manic episodes or harmful behaviors.
- Long-term suppression of growth in children: In children taking Adderall, height and weight should be monitored periodically since Adderall can decrease appetite.
- Seizures: In people with an irregular heartbeat or low seizure threshold, seizures can occur. Substances that lower the threshold include bupropion and alcohol.
- Worsened Raynaud’s phenomenon: Adderall can also act in the body as a blood vessel constrictor and make Raynaud’s phenomenon worse.
- Serotonin syndrome: Another side effect is the risk of a rare but serious side effect. Symptoms of serotonin syndrome include fever, tremor, irritability, and nausea.
- Onset or worsening of Tourette syndrome: Adderall can worsen tics.
Potential Drug Interactions With Adderall & Phentermine
Adderall and phentermine can cause serious weight loss if combined. Substances that increase serotonin can interact with Adderall. Adderall can also interact with drugs that are metabolized by the same pathway. Antihistamines, like diphenhydramine (Benadryl), can counteract some of Adderall’s effects. Also, Adderall can delay the onset of some seizure medications. Adderall’s activity can also be reduced if used with a proton pump inhibitor, such as omeprazole. Also, it is not safe to take Adderall with alcohol.
Phentermine interacts with monoamine oxidase inhibitor medications. The risk of a high blood pressure crisis increases if both medications are used within 14 or fewer days of each other. Also, diabetes medication doses may need to be lowered to account for the reduced appetite from phentermine. Some blood pressure medications’ effects may also be decreased by phentermine.
Disclaimer: Taking certain medications, herbs, or supplements alongside Adderall and phentermine can change how these medications work in your body or increase the risk of serious side effects. This article does not consider all the possible interactions. Please let your doctor, psychiatrists, and pharmacists know about all the products you currently use, such as prescription medication, nonprescription drugs, and herbal supplements. Do not start, stop, or change the dosage of any medicines without your doctor’s approval.
Can You Take Adderall & Phentermine Together?
The combination of Adderall and phentermine can cause or risk worsening heart conditions. Adderall raises the hormone norepinephrine. Phentermine also raises norepinephrine hormones in addition to epinephrine. These hormones cause an increase in blood pressure and heart rate, and could lead to heart disease. The combination can also cause severe weight loss.
Phentermine Vs. Adderall Cost
Most insurance policies will cover Adderall for treating ADHD and phentermine for promoting weight loss. However, your insurance may dictate the use of one medication over another. You may have a copay (a charge at the pharmacy), or your insurance may not cover them at all for off-label uses. If your insurance doesn’t cover them, you can find a coupon card for about $21 for Adderall and about $17 for phentermine.5, 6
Which Is Right for You: Adderall or Phentermine?
The medication best for your needs can depend on many factors. You may consider online pharmacy services if seeing a doctor in person isn’t feasible. They can help you consider the benefits and risks of each medication. For example, Adderall has fewer side effects that can affect the heart, while phentermine has a lower abuse potential.
How to Get a Prescription for Phentermine or Adderall
Phentermine and Adderall are only available by prescription from doctors such as your primary care doctor, nurse practitioner, or psychiatrist. They can help you consider these medications as a treatment by going through your medical and drug histories to see which one is right for you. They can help you learn and understand more about your condition, and how to get Adderall, phentermine, or consider a different treatment.
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Questions to Ask Your Health Team About Adderall & Phentermine
You may have additional questions about the use of Adderall or phentermine for weight loss. Questions to ask your doctor include how well each works for weight loss and their safety concerns. You may also need to discuss non-drug options if you take phentermine, as it is only approved if combined with lifestyle strategies. It’s important to have open communication with your doctor and come to your appointment prepared with any questions or concerns you have.
Questions to ask your prescriber about Adderall and phentermine include:
- Is it safe to take Adderall or phentermine with my other medications?
- Will Adderall or phentermine be covered by my insurance?
- Does my medical history increase my risk of side effects for either?
- How long can I expect side effects to last?
- How often should I see you for checkups while taking Adderall or phentermine?
- What should I do if I am unsure whether either of these medications is right for me?
- If I have ADHD and weight loss plans, is it safe to take them together?
- Do other ADHD medications help with weight loss?
- How long do I need to take Adderall or phentermine?
- How can I prevent severe side effects of Adderall and phentermine?
- What non-drug options can I do to help with my symptoms?
- If these medications aren’t suitable for me, are there Adderall or phentermine alternatives to consider?
In My Experience
“In my experience, Adderall and phentermine are generally well-tolerated. The most common side effect of Adderall is loss of appetite. Monitor your eating habits with each of these medications. Also, phentermine does not usually cause heart problems, though it is associated with several risks. Talk to your doctor about the risks and benefits of either medication and whether one of them is suitable for you.”
Choosing Therapy strives to provide our readers with mental health content that is accurate and actionable. We have high standards for what can be cited within our articles. Acceptable sources include government agencies, universities and colleges, scholarly journals, industry and professional associations, and other high-integrity sources of mental health journalism. Learn more by reviewing our full editorial policy.
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DailyMed – ADDERALL- dextroamphetamine saccharate, amphetamine aspartate, dextroamphetamine sulfate, and amphetamine sulfate tablet. (2023). DailyMed.nlm.nih.gov. Retrieved from https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm
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Gadde, K. M., Allison, D. B., Ryan, D. H., Peterson, C. A., Troupin, B., Schwiers, M. L., & Day, W. W. (2011). Effects of low-dose, controlled-release, phentermine plus topiramate combination on weight and associated comorbidities in overweight and obese adults (CONQUER): a randomised, placebo-controlled, phase 3 trial. Lancet (London, England), 377(9774), 1341–1352. Retrieved from https://doi.org/10.1016/S0140-6736(11)60205-5
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