Severe Side Effects With Phentermine or Adipex

Adipex-P is a brand name for the drug phentermine, which doctors prescribe to assist in weight loss. A stimulant and appetite suppressant, the medication is meant for obese people to use on a short-term basis along with a diet and exercise program. Some severe side effects are possible.

Primary Pulmonary Hypertension

• Primary pulmonary hypertension is a possible side effect of phentermine use. Signs include difficulty breathing, ankle swelling, blue lips or skin, chest pain, dizziness, fainting, fatigue and weakness.

Other Cardiovascular Effects

• Other cardiovascular side effects associated with phentermine use include high blood pressure and an increase in heart rate.

Drug Interactions

• Phentermine interacts with several other drugs, including tricyclic antidepressants. Combining it with fenfluramine is very dangerous. Phentermine also may be life-threatening if taken within 14 days of previously taking a monoamine oxidase inhibitor (MAOI).

Concentration Problems

• Especially during the first few weeks, phentermine may affect the patient's ability to perform tasks requiring concentration, such as driving and operating machinery.

Allergic Reaction

• Rarely, people can experience an allergic reaction to phentermine. Signs are rash or hives, itching, swelling, difficulty breathing and difficulty swallowing.