Acronyms
- ER - Extended release
- IR - Immediate release
- ODT - Orally-disintegrating tablet
- Phen - Phentermine
Benzphetamine IR
Didrex®
Didrex®
Dosage forms
Tablet
- 25 mg
- 50 mg
Dosing
Weight loss
- Starting: 25 - 50 mg once daily
- Maintenance: 25 - 50 mg one to three times a day
- Max: 150 mg/day
- Take midmorning
Kidney disease
- Benzphetamine has not been studied in kidney disease
Liver disease
- Benzphetamine has not been studied in liver disease
Generic / Price
- YES/$
Other
- DEA Schedule III
- Tablets are scored so they may be cut in two
Diethylpropion IR
Tenuate®
Tenuate®
Dosage forms
Tablet
- 25 mg
Dosing
Weight loss
- Dosing: 25 mg three times a day
- Max: 100 mg/day
- Take one hour before meals
- A midevening dose may be added to overcome night hunger
Kidney disease
- Diethylpropion is extensively excreted in the urine, and exposure is increased in kidney disease. Use caution.
Liver disease
- Diethylpropion has not been studied in liver disease
Generic / Price
- YES/$
Other
- DEA Schedule IV
- Usual starting dose is 25 mg three times a day before meals
- May take a fourth dose midevening to overcome night hunger
Diethylpropion ER
Tenuate Dospan®
Tenuate Dospan®
Dosage forms
Tablet, extended-release
- 75 mg
Dosing
Weight loss
- Dosing: 75 mg once daily
- Max: 75 mg once daily
- Take midmorning
Kidney disease
- Diethylpropion is extensively excreted in the urine, and exposure is increased in kidney disease. Use caution.
Liver disease
- Diethylpropion has not been studied in liver disease
Generic / Price
- YES/$
Other
- DEA Schedule IV
- Do not cut, chew, or crush tablet
Phendimetrazine IR
Bontril® PDM
Bontril® PDM
Dosage forms
Tablet
- 35 mg
Dosing
Weight loss
- Dosing: 35 mg two to three times a day
- Max: 210 mg/day (2 tablets 3 times a day)
- Take one hour before meals
Kidney disease
- Phendimetrazine is primarily excreted by the kidneys, and exposure is increased in renal disease. Use caution.
Liver disease
- Phendimetrazine has not been studied in liver disease
Generic / Price
- YES/$
Other
- DEA Schedule III
- In some cases, half a tablet (17.5 mg) per dose may be adequate
- Tablets are scored so they may be cut in two
Phendimetrazine ER
Bontril®
Bontril®
Dosage forms
Capsule, extended-release
- 105 mg
Dosing
Weight loss
- Dosing: 105 mg once daily
- Max: 105 mg once daily
- Take 30 - 60 minutes before morning meal
Kidney disease
- Phendimetrazine is primarily excreted by the kidneys, and exposure is increased in renal disease. Use caution.
Liver disease
- Phendimetrazine has not been studied in liver disease
Generic / Price
- YES/$
Other
- DEA Schedule III
Phentermine IR
Adipex-P®
Adipex-P®
Dosage forms
Tablet
- 37.5 mg
Capsule
- 15 mg
- 30 mg
- 37.5 mg
Dosing
Weight loss
- Dosing: 37.5 mg once daily
- Max: 37.5 mg once daily
- Tablet can be split and given twice a day
- May take before breakfast or 1-2 hours after breakfast
- Phentermine patient handout
Kidney disease
- CrCl ≥ 30 ml/min: no dose adjustment necessary
- CrCl 15 - 29 ml/min: maximum dose is 15 mg/day
- CrCl < 15 ml/min: DO NOT USE
Liver disease
- Phentermine has not been studied in liver disease
Generic / Price
- YES/$
Other
- DEA Schedule IV
- For some patients, half tablet (18.75 mg) daily may be adequate
- In some cases, it may be desirable to give half tablets (18.75 mg) two times a day
- Tablets are scored so that they may be cut in two
Phentermine IR
Lomaira™
Lomaira™
Dosage forms
Tablet
- 8 mg
Dosing
Weight loss
- Dosing: 1 tablet three times a day 30 minutes before meals
- Max: 8 mg three times a day
- Take 30 minutes before meals
- Tablet may be halved for 4 mg dose
Kidney disease
- CrCl ≥ 30 ml/min: no dose adjustment necessary
- CrCl 15 - 29 ml/min: maximum dose is 15 mg/day
- CrCl < 15 ml/min: DO NOT USE
Liver disease
- Phentermine has not been studied in liver disease
Generic / Price
- NO/$
Other
- DEA Schedule IV
- Tablets are scored so that they may be halved
Phentermine
Suprenza™
Suprenza™
Dosage forms
Tablet, orally-disintegrating
- 15 mg
- 30 mg
- 37.5 mg
Dosing
Weight loss
- Dosing: 15 - 37.5 mg once daily
- Max: 37.5 mg once daily
- May be taken without regard to food
Kidney disease
- CrCl ≥ 30 ml/min: no dose adjustment necessary
- CrCl 15 - 29 ml/min: maximum dose is 15 mg/day
- CrCl < 15 ml/min: DO NOT USE
Liver disease
- Phentermine has not been studied in liver disease
Generic / Price
- NO/$$$$
Other
- DEA Schedule IV
- Place tablet on tongue where it will dissolve, then swallow with or without water
- Kidney disease
- Benzphetamine
- Benzphetamine has not been studied in kidney disease
- Diethylpropion
- Diethylpropion is extensively excreted in the urine, and exposure is increased in kidney disease. Use caution.
- Phendimetrazine
- Phendimetrazine is primarily excreted by the kidneys, and exposure is increased in renal disease. Use caution.
- Phentermine
- CrCl ≥ 30 ml/min: no dose adjustment necessary
- CrCl 15 - 29 ml/min: maximum dose is 15 mg/day
- CrCl < 15 ml/min: DO NOT USE
- Liver disease
- Benzphetamine
- Benzphetamine has not been studied in liver disease
- Diethylpropion
- Diethylpropion has not been studied in liver disease
- Phendimetrazine
- Phendimetrazine has not been studied in liver disease
- Phentermine
- Phentermine has not been studied in liver disease
DRUG INTERACTIONS
- NOTE: The drug interactions presented here are NOT all-inclusive. Other interactions may exist. Drug interaction checkers provide the most efficient and practical way to check for interactions among multiple medications. A free interaction checker is available from Drugs.com (see Drugs.com interactions checker).
- All sympathomimetic amines
- MAO inhibitors - concomitant use of MAO inhibitors and phentermine increases the risk of hypertensive crisis; therefore, they should not be taken within 14 days of each other.
- Medications that affect the CNS - any medication that has CNS effects (e.g. antidepressants, antipsychotics, seizure medications, insomnia drugs, bipolar medications) may potentially be affected by the stimulant properties of sympathomimetic amines
- Serotonergic medications - case reports of serotonin syndrome have been reported in patients taking sympathomimetic amines with other serotonergic medications
- Metabolism and clearance
- The metabolism of sympathomimetic amines is not well defined
PRICE ($) INFO
- $ = 0 - $50
- $$ = $51 - $100
- $$$ = $101 - $150
- $$$$ = > $151
- Pricing based on one month of therapy at standard dosing in an adult
- Pricing based on information from GoodRX.com®
- Pricing may vary by region and availability
BIBLIOGRAPHY
- 1 - PMID 11493122
- 2 - PMID 19564877
- 3 - PMID 15526396
- 4 - PMID 7471128
- 5 - PMID 17066505
- 6 - Phentermine package insert
- 7 - Diethylpropion package insert
- 8 - PMID 11104741
- 9 - PMID 10713017
- 10 - PMID 20920040
- 11 - PMID 9731087
- 12 - Suprenza PI
- 13 - PMID 21481449
- 14 - Didrex PI
- 15 - Bontril PI