Adderall Vs. Phentermine: Drug Comparison

The information below is about Adderall XR^®, an extended-release formulation of mixed salts of a single-entity amphetamine product. This information may not be accurate for the immediate-release formulation, Adderall^®.

Adderall XR (amphetamine/dextroamphetamine extended-release) contains amphetamine, a Schedule II controlled substance. It is a stimulant medication used primarily to treat attention-deficit hyperactivity disorder (ADHD) by increasing levels of dopamine and norepinephrine in the brain, which helps improve focus, attention, and impulse control. Its FDA-approved indications include ADHD in both children and adults, and it may also be used to treat narcolepsy, though this is more common with immediate-release formulations. Adderall XR comes in capsule form and is designed for once-daily dosing. Common side effects include insomnia, decreased appetite, and increased heart rate, while serious warnings include a boxed warning for potential abuse, dependence, and cardiovascular risks, especially in individuals with underlying heart conditions or a history of substance abuse. It also interacts with certain other medications.

Phentermine is the active ingredient in brand-name medications including Adipex-P^®. The information below is about brand name Adipex-P. According to the FDA, “Generic medicines use the same active ingredients as brand-name medicines and work the same way, so they have the same risks and benefits as the brand-name medicines.”

Adipex-P (phentermine hydrochloride) is a prescription medication used as a short-term adjunct to weight loss in patients with obesity. It works as an appetite suppressant by stimulating the central nervous system, which increases heart rate and blood pressure while reducing hunger. Adipex-P is typically prescribed alongside a reduced-calorie diet and exercise regimen to enhance weight loss efforts. Common side effects include increased heart rate, dry mouth, insomnia, and nervousness. It is important to note that Adipex-P is intended for short-term use due to the potential for dependence and other adverse effects​.

Central nervous system (CNS) stimulant

Sympathomimetic amine anorectic

Adderall XR (mixed salts of a single-entity amphetamine product) is indicated:

• For the treatment of attention deficit hyperactivity disorder (ADHD) in adults and pediatric patients 6 years and older.

Adipex-P (phentermine hydrochloride) is indicated:

• As a short-term adjunct (a few weeks) in a regimen of weight reduction based on exercise, behavioral modification and caloric restriction in the management of exogenous obesity for patients with an initial body mass index greater than or equal to 30 kg/m², or greater than or equal to 27 kg/m² in the presence of other risk factors (e.g., controlled hypertension, diabetes, hyperlipidemia)

• Typically taken orally once daily

• Comes in 5 mg, 10 mg, 15 mg, 20 mg, 25 mg, and 30 mg extended-release capsules

• Typically taken orally once daily

• Comes in 37.5 mg tablets

Pediatric patients ages 6 to 12: Most common adverse reactions (≥5% and with a higher incidence than on placebo) were:

• Loss of appetite

• Insomnia

• Abdominal pain

• Emotional lability

• Vomiting

• Nervousness

• Nausea

• Fever

Pediatric patients ages 13 to 17: Most common adverse reactions (≥5% and with a higher incidence than on placebo) were:

• Loss of appetite

• Insomnia

• Abdominal pain

• Weight loss

• Nervousness

Adults: Most common adverse reactions ≥5% and with a higher incidence than on placebo were:

• Dry mouth

• Loss of appetite

• Insomnia

• Headache

• Weight loss

• Nausea

• Anxiety

• Agitation

• Dizziness

• Fast heart beat

• Diarrhea

• Weakness

• Urinary tract infections

Adverse events have been reported in the following systems:

• Cardiovascular

• Central nervous system

• Gastrointestinal

• Allergic

• Endocrine

• Known hypersensitivity or idiosyncrasy to amphetamine

• During or within 14 days following the administration of monoamine oxidase inhibitors (MAOI)

• Drug interactions: alkalinizing agents (GI antacids and urinary), acidifying agents (GI and urinary)

• History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension)

• During or within 14 days following the administration of monoamine oxidase inhibitors

• Hyperthyroidism

• Glaucoma

• Agitated states

• History of drug abuse

• Pregnancy

• Nursing

• Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines

• Drug interactions: Monoamine oxidase inhibitors, alcohol, insulin and oral hypoglycemics, adrenergic neuron blocking drugs

• Risks to patients with serious cardiac disease

• Increased blood pressure and heart rate

• Psychiatric adverse reactions

• Long-term suppression of growth in pediatric patients

• Seizures

• Peripheral vasculopathy, including Raynaud’s phenomenon

• Serotonin syndrome: Increased risk when coadministered with serotonergic agents (e.g., SSRIs, SNRIs, triptans), but also during overdosage situations

• Motor and verbal tics, and worsening of Tourette’s syndrome

• Pregnancy: May cause fetal harm

• Lactation: Breastfeeding not recommended

• Coadministration with other drugs for weight loss is not recommended

• Rare cases of primary pulmonary hypertension have been reported

• Rare cases of serious regurgitant cardiac valvular disease have been reported

• Tolerance to the anorectic effect usually develops within a few weeks

• Adipex-P may impair the ability of the patient to engage in potentially hazardous activities such as operating machinery or driving a motor vehicle

• Risk of abuse and dependence

• Concomitant alcohol use may result in an adverse drug reaction

• Use caution in patients with even mild high blood pressure

• A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients

• Breastfeeding: Discontinue drug or nursing taking into consideration importance of drug to mother

WARNING: ABUSE, MISUSE, AND ADDICTION

Adderall XR has a high potential for abuse and misuse, which can lead to the development of a substance use disorder, including addiction. Misuse and abuse of CNS stimulants, including Adderall XR, can result in overdose and death:

• Before prescribing Adderall XR, assess each patient’s risk for abuse, misuse, and addiction.

• Educate patients and their families about these risks, proper storage of the drug, and proper disposal of any unused drug.

• Throughout treatment, reassess each patient’s risk and frequently monitor for signs and symptoms of abuse, misuse, and addiction.

*This information is from the label for brand name Adderall XR^®. See the Full Prescribing Information for more complete information. Dextroamphetamine sulfate, dextroamphetamine saccharate, amphetamine sulfate, and amphetamine aspartate, the active ingredients in Adderall XR, may also be the active ingredients in other medications, and this information may not be accurate for all medications that include the active ingredients dextroamphetamine sulfate, dextroamphetamine saccharate, amphetamine sulfate, and amphetamine aspartate.

*This information is from the label for brand name Adipex-P^®. See the Full Prescribing Information for more complete information. Phentermine, the active ingredient in Adipex-P, may also be the active ingredient in other medications, and this information may not be accurate for all medications that include the active ingredient phentermine.