6 ADVERSE REACTIONS The following adverse reactions are described, or described in greater detail, in other sections: • Primary pulmonary hypertension [ see Warnings and Precautions ( 5.2 ) ] • Valvular heart disease [ see Warnings and Precautions ( 5.3 ) ] • Effect on the ability to engage in potentially hazardous tasks [ see Warnings and Precautions ( 5.5 ) ] • Withdrawal effects following prolonged high dosage administration [ see Drug Abuse and Dependence ( 9.3 ) ] The following adverse reactions to phentermine have been identified: Cardiovascular: Primary pulmonary hypertension and/or regurgitant cardiac valvular disease (see WARNINGS ), palpitation, tachycardia, elevation of blood pressure. Central Nervous System: Overstimulation, restlessness, dizziness, insomnia, euphoria, dysphoria, tremor, headache; rarely psychotic episodes at recommended doses. Gastrointestinal: Dryness of the mouth, unpleasant taste, diarrhea, constipation, other gastrointestinal disturbances. Allergic: Urticaria. Endocrine: Impotence, changes in libido.