Phentermine vs. Adderall for ADHD

In this article:

• Main differences
• Conditions treated
• Is phentermine or Adderall more effective?
• Coverage and cost
• Side effects
• Drug interactions
• Drug warnings
• FAQ

In this article

• Main differences
• Conditions treated
• Is phentermine or Adderall more effective?
• Coverage and cost
• Side effects
• Drug interactions
• Drug warnings
• FAQ

Phentermine and Adderall are prescription drugs that stimulate the central nervous system (CNS). As CNS stimulants, they increase the brain’s release of dopamine and norepinephrine, which may help suppress appetite or improve focus and attention. Phentermine is FDA‑approved for short‑term weight loss, while Adderall is approved for attention deficit hyperactivity disorder (ADHD) and narcolepsy. However, some providers may prescribe one or the other off‑label based on a person’s condition.

RELATED: What is phentermine? | What is Adderall?

What are the main differences between phentermine and Adderall?

Phentermine is a generic medication known by brand names like Adipex-P and Lomaira. It is also combined with topiramate under the brand name Qsymia. Phentermine has strong appetite suppressant effects and is typically prescribed as a 37.5 mg oral tablet taken once daily. Phentermine is reserved for short-term use, usually a few weeks to 12 weeks.

Adderall is a brand-name drug that combines amphetamine and dextroamphetamine. It comes in both immediate-release (IR) tablets taken several times a day and extended-release (XR) capsules taken once daily. Typical daily doses range from 5 mg to 40 mg, and it is often prescribed long-term to manage ADHD. 

Conditions treated by phentermine and Adderall

Phentermine is approved for weight loss in adults with obesity (BMI ≥30) or those who are overweight (BMI ≥27) with conditions like high blood pressure or diabetes. It works as an appetite suppressant and is meant to be used short-term, along with a reduced-calorie diet and increased physical activity.

Adderall is approved to treat ADHD and narcolepsy. ADHD involves symptoms like inattention and hyperactivity, while narcolepsy causes excessive daytime sleepiness and sudden sleep attacks.

Because both are stimulants, they may sometimes be prescribed off-label. Adderall can lead to weight loss as a side effect, and some reports suggest phentermine may help with ADHD. In specific cases, doctors or healthcare providers may prescribe these drugs for off-label uses.

Is phentermine or Adderall more effective?

Both phentermine and Adderall can be effective, but the better choice depends on the condition being treated and a person’s overall health. There are few studies directly comparing the two.

Phentermine is generally preferred as an appetite suppressant because it’s FDA approved for weight loss. While Adderall is not approved for this purpose, weight loss can be a common side effect due to its effects on appetite. 

On the other hand, Adderall is the standard option for managing ADHD and narcolepsy. Some small studies and reports suggest phentermine may have benefits for ADHD and narcolepsy, but the evidence is far more limited.

It’s recommended to consult a healthcare provider to discuss the most appropriate treatment option. 

Coverage and cost comparison of phentermine vs. Adderall

Adderall is usually covered by many insurance plans, with out-of-pocket costs varying by plan. Generic versions are often more accessible and are commonly included under Medicare Part D. 

Coverage for phentermine is more restricted since insurance plans usually won’t cover weight loss medications. Because it’s prescribed for weight loss, phentermine may also come with higher out-of-pocket costs. 

For those without insurance, retail prices vary. Phentermine is a generic drug that is often more economical than brand-name Adderall, but both can still add up. Using a SingleCare card may help lower costs, especially for people paying cash.

* Cost at time of publication. Drug prices fluctuate and vary by pharmacy and location.

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Common side effects of phentermine vs. Adderall

Phentermine and Adderall share many of the same side effects since they work in similar ways. Common side effects may include insomnia, dry mouth, decreased appetite, nausea, tremor, diarrhea, and constipation.

Both drugs can also cause more serious side effects. For example, they can cause increased heart rate and blood pressure (hypertension), which can increase the risk of heart problems. In rare cases, allergic reactions may occur and require immediate medical care.

It’s important to discuss possible side effects with a healthcare provider before starting either medication.

This may not be a complete list of adverse effects that can occur. Please refer to your healthcare provider to learn more. Source: DailyMed (Phentermine), DailyMed (Adderall) 

Drug interactions of phentermine vs. Adderall

Phentermine and Adderall share several important drug interactions. Neither should be used with monoamine oxidase inhibitors (MAOIs) or within 14 days of stopping one, as doing so can increase the risk of dangerously high blood pressure and serotonin syndrome. 

Both drugs should be used with caution alongside antidepressants such as selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), and tricyclic antidepressants (TCAs). Combining phentermine or Adderall with these drugs may increase serotonin levels and trigger serotonin syndrome. 

Phentermine and Adderall can also reduce the effectiveness of blood pressure medications (antihypertensives). Taking phentermine and Adderall with antihypertensives could make blood pressure harder to control and increase the risk of heart problems.

Adderall may not be absorbed as quickly when taken with proton pump inhibitors (PPIs) since they reduce stomach acid. In addition, acidifying agents might decrease how much Adderall the body absorbs, leading to reduced effectiveness, while alkalinizing agents may increase the blood levels of Adderall, leading to increased effects.

Tell a healthcare provider about any prescription, over-the-counter medications, or herbal supplements before starting phentermine or Adderall.

This is not a complete list of drug interactions. Please consult your healthcare provider before taking these medications.

RELATED: Phentermine alternatives | Adderall alternatives

Warnings of phentermine and Adderall

Phentermine may cause high blood pressure in the lungs (pulmonary hypertension). Stop treatment if symptoms like chest pain, shortness of breath, or dizziness occur. It may also affect alertness, which could affect driving or operating machinery.

People with heart disease should use caution with Adderall, as rare cases of sudden death have been reported. Adderall may also worsen mental health conditions, slow growth in children, and trigger seizures in some individuals.

Adderall is a Schedule II controlled substance with a high potential for abuse and addiction. Phentermine is a Schedule IV controlled substance, meaning it has a lower risk of misuse and dependence.

Neither medication is considered safe during pregnancy or breastfeeding. Phentermine and Adderall may harm an unborn baby and pass into breast milk, potentially causing harm to an infant.

Frequently asked questions about phentermine vs. Adderall

What is phentermine?

Phentermine is a prescription medication FDA approved for weight loss. It acts as an appetite suppressant and is usually taken as an oral tablet or capsule. Phentermine is taken once daily.

What is Adderall?

Adderall contains a combination of amphetamine salts and is mainly used to treat ADHD symptoms. It also helps manage narcolepsy. Adderall is available as an oral tablet that’s taken every four to six hours. Adderall XR is an extended-release tablet taken once daily.

Are phentermine and Adderall the same?

No, phentermine and Adderall are not the same. Although both are stimulant medications, phentermine is approved for weight management, while Adderall is approved for ADHD and narcolepsy.

Is phentermine or Adderall better?

The effectiveness of phentermine and Adderall depends on a person’s overall condition and treatment response. Phentermine may be a better choice for weight loss, although Adderall might be prescribed off-label for this purpose. Consult a healthcare professional for medical advice on the most effective option. 

Can I use phentermine or Adderall while pregnant?

Phentermine and Adderall both carry risks during pregnancy. They should only be used if the potential benefits outweigh the risks to an unborn baby.

Can I use phentermine or Adderall with alcohol?

Avoid consuming alcohol with either phentermine or Adderall, as it may increase the risk of side effects of either drug, such as dizziness and headache. Drinking alcohol could also increase the risk of misusing Adderall or phentermine.