Side Effects
Along with its needed effects, Phentermine may cause unwanted side effects, some being symptoms of serious heart or lung problems.
Please consult your doctor immediately if you notice:
- Chest pain
- Decreased ability to exercise
- Fainting
- Swelling of feet or lower legs
- Trouble in breathing
Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine.
Inform your doctor if any of the following side effects persist or are bothersome:
More Common Symptoms
- Depression
- Drowsiness
- Increased blood pressure
- Irritability
- Nervousness
- Sense of well-being
- Tiredness
Less Common to Rare Symptoms
- Blurred vision
- Change in sexual desire
- Clumsiness
- Confusion
- Diarrhea
- Dizziness
- Dry mouth
- Headache
- Irregular heartbeat
- Nausea or vomiting
- Psychosis
- Skin rash or itching
- Stomach pain
- Tiredness
- Unpleasant taste
Other side effects not listed above may occur in some patients. If you notice any other side effects, please inform your doctor.
Possible Overdose Symptoms:
| Confusion | Convulsions (seizures) |
| Dizziness | Fast Breathing |
| Fever | Hallucinations |
| Hostility with urge to attack | Irregular blood pressure |
| Irregular heartbeat | Lightheadedness or Fainting |
| Mental Depression, following a period of excitement | Tremors, Trembling, or Shaking |
| Overactive Reflexes | Panic |
| Restlessness | Severe nausea, vomiting or diarrhea |
| Stomach cramps | Tiredness or Weakness |
Physical or Mental Dependence on Phentermine
If you have been taking Phentermine for a long time or in large doses and you think you may have become mentally or physically dependent on it, please speak to your doctor.
Some signs of dependence on Phentermine (or other appetite suppressants) are:
- a strong desire or need to continue taking the medicine.
- a need to increase the dose to receive the effects of the medicine.
Withdrawal side effects may include:
- Changes in personality
- Excessive, excited activity
- Irritability (severe)
- Extreme tiredness or weakness
- Mental depression or illness (severe)
- Nausea or vomiting
- Skin disease
- Stomach Cramps or Pain
- Trembling
- Trouble in Sleeping or Nightmares (severe)