Two medicines, side by side
Diethylpropion vs phentermine
Diethylpropion and phentermine are both labeled for weight management. Drugs@FDA records approvals of diethylpropion since 1959 and of phentermine since 1973. Pharmacies paid $0.238 per diethylpropion 25 mg tablet and $0.0727 per phentermine 37.5 mg tablet (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like.
Check it at the source: the diethylpropion FDA label on DailyMed (effective December 31, 2019); the phentermine FDA label on DailyMed (effective April 18, 2024).
Highlights of the diethylpropion record
Diethylpropion (Tenuate) · label of December 31, 2019
Used for
From the label: indicationsDiethylpropion hydrochloride tablets USP, 25 mg are indicated in the management of exogenous obesity as a short-term adjunct (a few weeks) in a regimen of weight reduction based on caloric restriction in patients with an initial body mass index (BMI) of 30 kg/m 2 or higher and who have not responded to appropriate weight reducing regimen (diet and/or exercise) alone. […]
On the market
- Earliest approval on file
- August 6, 1959
- Generic labelers
- 13 labelers
- Pharmacy cost
- $0.238 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 2
Highlights of the phentermine record
Phentermine (Lomaira) · label of April 18, 2024
Used for
From the label: indicationsPhentermine Hydrochloride, USP 15 mg and 30 mg is indicated as a short-term (a few weeks) adjunct 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/m 2 , or greater than or equal to 27 kg/m 2 in the presence of other risk factors (e.g., controlled hypertension, diabetes, hyperlipidemia). […]
On the market
- Earliest approval on file
- August 14, 1973
- Generic labelers
- 25 labelers
- Pharmacy cost
- $0.0727 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 9
Source: FDA drug labels via openFDA (Diethylpropion label of December 31, 2019, Phentermine label of April 18, 2024); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do diethylpropion and phentermine differ on the record?
Both are in FDA's class sympathomimetic amine anorectics.
Generics: diethylpropion since 1979; phentermine since 1976 (Drugs@FDA).
| Diethylpropion | Phentermine | |
|---|---|---|
| Labeled for | Weight management | Weight management |
| Pharmacologic class | Sympathomimetic Amine Anorectic | Sympathomimetic Amine Anorectic |
| How it works (label) | n/a | Phentermine is a sympathomimetic amine with pharmacologic activity similar to the prototype drugs of this class used in obesity, amphetamine (d- and dll-amphetamine). |
| Half-life (label) | Using a phosphorescence assay that is specific for basic compounds containing benzoyl group, the plasma half-life of the aminoketone metabolites is estimated to be between 4 to 6 hours. | n/a |
| Earliest approval on file (Drugs@FDA) | August 6, 1959 | August 14, 1973 |
| First generic approved | August 15, 1979 | February 24, 1976 |
| Generic labelers (NDC) | 13 labelers | 25 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.238 per tablet (Diethylpropion 25 mg tablet) | $0.0727 per tablet (Phentermine 37.5 mg tablet) |
| 12-month price change | +12% | +3% |
| Boxed warning | No | No |
| Shortage now | No current entry | No current entry |
| Recalls recorded | 2 | 9 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 127 | 6,389 |
| DEA schedule | CIV | CIV |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
What next?
- Alternatives to diethylpropion
- every medicine labeled for the same conditions