Phentermine Dosage

How and when to take phentermine

Phentermine should be taken on an empty stomach, once daily, prior to breakfast. If in tablet form, the tablet may be broken or cut in half. Do NOT break, crush, or chew capsules.

As phentermine may disrupt normal sleep patterns, avoid taking a dose late in the day. If taking more than one dose a day, take the last dose approximately 4-6 hours prior to going to bed.

The following information is specific only to the average doses of phentermine. The recommended dose of phentermine may be different for different patients. If your dose is different, do NOT change it unless your doctor tells you to do so.

Adults under age 60 taking phentermine

  • Oral dosage form (Capsules) - 15 to 37.5 mg once/day before breakfast or 1-2 hours after breakfast.
  • Oral dosage form (Tablets) - 8 to 37.5 mg once/day before breakfast or 1-2 hours after breakfast. Instead of taking it once a day, your doctor may tell you to take 15 to 37.5 mg in divided doses one-half hour before meals.
  • Oral resin dosage form (Capsules) - 15 to 30 mg once/day before breakfast.

Adults age 60 and over taking phentermine: A reduced dosage may be necessary. Consult your physician.

Infants and children taking phentermine: Phentermine is NOT recommended for children under age 16.

Maximum dosage recommendations

Take phentermine ONLY as directed by your doctor.

  • Do NOT take more of it
  • Do NOT take it more often, and
  • Do NOT take it for a longer time than your doctor ordered.

If too much phentermine is taken, it may cause unwanted effects or become habit-forming.

Please speak with your doctor if you think that phentermine is not working properly after you have taken it for a few weeks. DO NOT increase the dose.

However, to enhance the effects of your phentermine pills or after you stop taking phentermine, officially recommends Phen Caps as a supplement.

If you want to learn more about Phen Caps, click here.

Missed dose

If you miss a dose, take it as soon as possible. However, if it is almost time for the next dose, skip the missed dose and take only the scheduled dose. Do NOT double the dose.

In case of overdose

It is unlikely for an overdose of phentermine to be life-threatening. If you or someone you know takes a much larger dose than recommended, please phone a doctor, 911, or the nearest poison control center immediately.

Sharing your phentermine prescription

Do NOT share your phentermine prescription with others.

> For answers to Frequently Asked Questions see our FAQs section

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