Long-Term Effects of Adipex

Adipex, generically known as phentermine, is a medication commonly prescribed to suppress appetite. An amphetamine-like medication, Adipex may be beneficial in helping a patient lose weight, but carries significant, serious side effects, states MayoClinic.com. Adipex is only recommended to help a patient initially start a weight-loss program. Although Adipex may be somewhat effective, a patient should be aware of the long-term side effects.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Pulmonary Hypertension

A long-term side effect of Adipex is pulmonary hypertension, states Drugs.com. This occurs because the chemical substances in Adipex can cause vasoconstriction, or shrinking, of the blood vessels in the lungs. When these blood vessels shrink blood can back up in the lungs and into the heart. This results in shortness of breath and possibly chest pain depending on the severity of pulmonary hypertension. Medical care should be sought for this condition.


Drugs.com states that a patient taking long-term Adipex may experience constipation. This occurs because Adipex can affect certain receptors in the gastrointestinal tract that may cause swelling of the gastrointestinal tract, which will result in constipation. This can cause significant stomach pain, difficulty moving bowels and nausea. A patient that is constipated from long-term Adipex use should consult his doctor so that the doctor may prescribe a medication to relieve constipation or adjust the usage of Adipex.


A patient may experience difficulty falling asleep, or insomnia, states Drugs.com. This occurs because the chemicals in Adipex may affect certain parts of the brain that are responsible for making a patient fall asleep. Because these natural brain chemicals are out of balance a patient may find it difficult to fall asleep at night. This can further result in excessive fatigue and drowsiness throughout the day. In this case, a patient should not hesitate to alert his doctor that he is having difficulty sleeping and possibly fatigue the next day. A doctor will likely adjust the dosage of Adipex or prescribe a different medication.