Common Side Effects

• Common side effects include headache, anxiety, nervousness, impotence, diarrhea, constipation, insomnia, stomach upset, unpleasant taste lingering in the mouth, dry mouth, dizziness, overstimulation, sex drive changes, and trouble sleeping. If you have any of these side effects, and they do not subside, or if they happen to get worse with time, you need to speak with your doctor about them.
  
  

Serious Side Effects

• Some serious effects of Phentermine include shortness of breath, swelling in the feet or the legs, chest ache, tremors, chest pounding, rapid heartbeat, abnormal behavior, and passing out.
  
  

Allergic Reactions

• Severe allergic reactions to Phentermine are also unlikely. They can be dangerous, so it is crucial to immediately seek medical help if you feel that you might be experiencing one. Some signs to look out for are chest heaviness or tightness, swelling in the mouth, lips, tongue, or face, itching, trouble breathing, skin rash, and hives.
  
  

Caution

• Phentermine is not suitable or safe for everybody. It is vital to speak with your physician regarding whether the medication is safe for you, especially if you are allergic to any stimulants, have an overactive thyroid, arteriosclerosis, glaucoma, hypertension, diabetes, epilepsy, heart disease, thyroid disorder, anxiety disorder, or a past that includes alcohol or drug addiction.
  
  

Overdose

• Overdosing on Phentermine can be harmful. If you suspect that you have taken more than the recommended amount of Phentermine, you must immediately seek emergency medical care. Some symptoms of overdose include lightheadedness, passing out, stomach ache, fast breathing, restlessness, aggressiveness, diarrhea, nausea, throwing up, convulsions, confusion, disorientation, and hallucinations.