Phentermine Dosage

The recommended phentermine dosage for the capsule form is 15 mg, 30 mg, or 37.5 mg once a day. With the tablets, the recommended dose is 18.75 mg (half a tablet) or 37.5 mg (one tablet) once daily. If needed, your healthcare provider may increase your phentermine dosing to half a tablet twice a day. The medication is intended for short-term use only.

 

Phentermine Dosage: An Introduction

The dose of phentermine that your healthcare provider prescribes will vary depending on a number of factors, including:
 
  • Whether you develop bothersome or dangerous phentermine side effects
  • How you respond to the drug
  • The particular phentermine product
  • Other medical conditions you may have
  • Other medications you may currently be taking.
     
As is always the case, do not adjust your phentermine dose unless your healthcare provider specifically instructs you to do so.
 

Phentermine Dosing for Weight Loss

The recommended phentermine capsule dose for weight loss is 15 mg, 30 mg, or 37.5 mg once daily in the morning. For phentermine tablets, the recommended dose is 18.75 mg (half a tablet) or 37.5 mg (one tablet) once daily in the morning. If necessary, your healthcare provider may recommend taking half a tablet twice a day (although this increases the risk of insomnia) to control your appetite.
 
Phentermine is intended for short-term use only (for just a few weeks). Longer use is not likely to be effective, since the body adjusts to the appetite-suppressing properties of phentermine. Also, phentermine has the potential to be abused (which is another reason why phentermine use should be limited to just a few weeks).
 

General Information on Dosing With Phentermine

Considerations for people taking phentermine include the following:
 
  • Phentermine comes in tablet and capsule form. It is usually taken by mouth once daily, although some people may need to take it twice a day.
     
  • Phentermine should be taken either before breakfast or one to two hours after breakfast, depending on the particular phentermine product.
     
  • Phentermine should be combined with an appropriate diet. It is not meant to be used without dieting.
     
  • Do not take phentermine more often (or at higher doses) than prescribed, as this can lead to phentermine addiction or dependence.
     
  • For the medication to work properly, it must be taken as prescribed.
     
  • If you are unsure about anything related to your phentermine dosage, please talk to your doctor, nurse, or pharmacist.
     
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Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;