Common Side Effects

• Common side effects of phendimetrazine can include tremors (e.g., of the hand), nervousness, headaches and dizziness. You may also experience sleeping disturbances such as insomnia, diarrhea/constipation, dry mouth or bad taste in the mouth and changes in sexual drive (e.g., impotence).
  
  

Serious Side Effects

• In rare instances, an allergic response to phendimetrazine can occur. An allergic reaction can include difficulty breathing, throat tightening, swelling of the face, lips, tongue or throat, and hives. Other serious effects can include an irregular heartbeat, high blood pressure, visual disturbances (e.g., blurred vision) and confusion. In severe cases, hallucinations can happen, as can abnormal behavior (e.g., severe aggression).
  
  

Caution

• This medication is not recommended in women who are pregnant or breastfeeding. It is unknown if this medication is harmful to a fetus or if it is excreted in breast milk. This medication should not be used while driving or when using heavy machinery, since phendimetrazine can cause dizziness and sleepiness. Never chew or crush this medication, as it can result in the medication being released into the bloodstream at a faster rate. This can result in arrhythmia and possible serious effects that could be potentially dangerous, like falling into a coma.
  
  

Addiction

• Phendimetrazine is highly addictive. Using more than the recommended dose can result in a habit, forming dependency. According to MSN Health and Fitness, phendimetrazine can become physically and psychologically habit forming. Stopping the use of phendimetrazine can also result in severe withdrawal symptoms such as severe fatigue, depression, hyperactivity, irritability and insomnia.
  
  

Overdose

• In the occurrence of overdose, it is important to seek immediate medical attention. Symptoms of overdose can include confusion, extreme restlessness and behavioral disturbances like panic and anxiety. Heart arrhythmia, nausea/vomiting, diarrhea and abdominal cramping can also occur. In severe cases of overdose, convulsions, coma and death may occur, but this is a very rare occurrence.