Drug class: Amphetamine Derivatives
VA class: GA751
CAS number: 134-80-5

Medically reviewed by Drugs.com on Nov 11, 2024. Written by ASHP.

Introduction

Amphetamine congener; anorexigenic agent.

Uses for Diethylpropion

Exogenous Obesity

Adjunct to caloric restriction in the short-term management (a few weeks) of exogenous obesity.

Use in patients with initial body mass index (BMI) of ≥30 kg/m² who have not responded to appropriate weight-reducing regimen (diet and/or exercise) alone.

Use only for short-term monotherapy; not for use in combination with any other drug for weight loss.

Diethylpropion Dosage and Administration

General

• Teach patient to curtail overeating and consume a suitable diet to help induce and maintain weight loss.

Administration

Oral Administration

Administer conventional tablets orally 3 times daily, 1 hour before meals; may administer an additional dose in midevening if necessary.

Administer extended-release tablets orally once daily, in midmorning; swallow tablet whole.

Dosage

Available as diethylpropion hydrochloride; dosage expressed in terms of the salt.

Pediatric Patients

Exogenous Obesity

Oral

Children >16 years of age: Conventional tablets: 25 mg 3 times daily, given 1 hour before meals; may administer an additional 25 mg in midevening if needed to overcome hunger.

Oral

Children >16 years of age: Extended-release tablets: 75 mg once daily, given in midmorning.

Adults

Exogenous Obesity

Oral

Conventional tablets: 25 mg 3 times daily, given 1 hour before meals; may administer an additional 25 mg in midevening if needed to overcome hunger.

Extended-release tablets: 75 mg once daily, given in midmorning.

Special Populations

Geriatric Patients

Select dosage with caution, starting at lower end of dosage range, because of age-related decreases in hepatic, renal, and/or cardiac function and concomitant disease and drug therapy. (See Geriatric Use under Cautions.)

Cautions for Diethylpropion

Contraindications

• Pulmonary hypertension, hyperthyroidism, severe hypertension, glaucoma, or advanced arteriosclerosis.

• Agitated state or history of drug abuse.

• During or within 14 days of MAO inhibitor therapy.

• Concurrent therapy with other anorexigenic drugs.

• Known hypersensitivity or idiosyncrasy to sympathomimetic amines.

Warnings/Precautions

Warnings

Primary Pulmonary Hypertension

Risk of primary pulmonary hypertension (frequently fatal). Risk increased by 23-fold when anorexigenic agents are used for >3 months. Increased risk following repeated courses of diethylpropion cannot be ruled out.

Discontinue immediately if new onset or exacerbation of exertional dyspnea or unexplained symptoms of angina, syncope, or edema of the lower extremities occur, and evaluate for possible pulmonary hypertension.

Valvular Heart Disease

Valvular heart disease reported following use of some anorexigenic agents (e.g., fenfluramine, dexfenfluramine [both no longer commercially available in the US]), particularly when used for extended periods of time, at higher than recommended dosages, and/or in combination with other anorexigenic agents.

Valvulopathy reported rarely with diethylpropion alone, but causal relationship not established. Weigh potential risks against benefits of therapy.

Consider performing baseline cardiac evaluation to detect preexisting valvular heart diseases prior to initiation of therapy. Use not recommended in patients with known heart murmur or valvular heart disease. Echocardiogram during and after treatment may be useful for detecting any valvular disorders which may occur.

To limit unwarranted exposure and risks, continue therapy only if patient has achieved satisfactory weight loss (e.g., ≥4 pounds, or as determined by clinician and patient) within first 4 weeks of therapy.

Tolerance to Anorexigenic Effect

If tolerance develops, discontinue therapy; do not attempt to increase effect by exceeding recommended dosage.

CNS Effects

Performance of activities requiring mental alertness or physical coordination may be impaired. (See Advice to Patients.)

Abuse Potential

Potential for abuse; psychological dependence reported. Possible withdrawal syndrome upon discontinuance of therapy.

Hallucinations reported rarely following administration of high dosages. Psychotic episodes reported even with recommended dosages; psychosis abated following discontinuance of therapy.

Manifestations of chronic intoxication with anorexigenic agents may include psychosis resembling schizophrenia, severe dermatoses, marked insomnia, irritability, hyperactivity, and personality changes.

Abrupt discontinuance following prolonged high dosage may result in extreme fatigue, depression, and sleep EEG changes.

General Precautions

Prescribe and dispense in the smallest feasible quantity to minimize possibility of overdosage.

Hypertension

Use with caution in patients with hypertension. Contraindicated in those with severe hypertension.

Symptomatic Cardiovascular Disease

Use with caution in patients with symptomatic cardiovascular disease, including arrhythmias.

Epilepsy

Possible seizures in some patients with epilepsy. Carefully monitor such patients; dosage adjustment or discontinuance of therapy may be necessary.

Specific Populations

Pregnancy

Category B.

Congenital malformations reported; however, causal relationship not established.

Abuse during pregnancy may result in withdrawal symptoms in neonate.

Lactation

Distributed into milk. Caution if used in nursing women.

Pediatric Use

Safety and efficacy not established; use not recommended in children ≤16 years of age.

Geriatric Use

Insufficient experience in patients ≥65 years of age to determine whether geriatric patients respond differently than younger adults. Other clinical experience has not identified differences in responses between geriatric and younger patients. Select dosage with caution (see Geriatric Patients under Dosage and Administration); monitoring of renal function may be useful.

Renal Impairment

Possible increased risk of toxicity. (See Elimination Route under Pharmacokinetics.)

Common Adverse Effects

Precordial pain, arrhythmia (including ventricular arrhythmia), ECG changes, tachycardia, increased BP, palpitation, dyskinesia, blurred vision, overstimulation, nervousness, restlessness, dizziness, jitteriness, insomnia, anxiety, euphoria, depression, dysphoria, tremor, mydriasis, drowsiness, malaise, headache, cerebrovascular accident, vomiting, diarrhea, abdominal discomfort, dry mouth, unpleasant taste, nausea, constipation, urticaria, rash, ecchymosis, erythema, impotence, changes in libido, gynecomastia, menstrual upset, bone marrow depression, agranulocytosis, leukopenia.

Drug Interactions

Specific Drugs

Diethylpropion Pharmacokinetics

Absorption

Bioavailability

Readily and rapidly absorbed from the GI tract following oral administration.

Duration

Effects persist for about 4 hours following oral administration of conventional tablets.

Distribution

Extent

Diethylpropion and its active metabolites appear to cross the blood-brain barrier.

Diethylpropion and its metabolites cross the placenta and are distributed into milk.

Elimination

Metabolism

Extensively metabolized to active metabolites principally via biotransformation involving N-dealkylation and reduction.

Elimination Route

Diethylpropion and its metabolites are excreted principally in urine. Approximately 75–106% of the dose (as conventional tablets) is recovered in urine within 48 hours. Amount recovered following administration of extended-release tablets is not substantially different from that observed with conventional tablets.

Half-life

Approximately 4–6 hours (for aminoketone metabolites).

Stability

Storage

Oral

Conventional and Extended-release Tablets

Tight containers at room temperature, <30°C.

Actions

• Produces anorexigenic effect and loss of weight.

• Like other amphetamine derivatives, has no primary effect on appetite; anorexigenic action probably is secondary to CNS stimulation.

Advice to Patients

• Potential for drug to impair mental alertness or physical coordination; caution when driving or operating machinery until effects on individual are known.

• Importance of administering extended-release tablets whole.

• Importance of informing clinicians of existing or contemplated therapy, including prescription and OTC drugs, alcohol consumption, as well as any concomitant illnesses (e.g., glaucoma, seizures, hypertension, cardiac disease).

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.

• Importance of informing patients of other important precautionary information. (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

Subject to control under the Federal Controlled Substances Act of 1970 as a schedule IV (C-IV) drug.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

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