Tolerance to the anorectic effect usually develops within a few weeks. When this occurs, the recommended dose should not be exceeded in an attempt to increase the effect; rather, the drug should be discontinued.
Use of phendimetrazine within 14 days following the administration of monoamine oxidase inhibitors may result in a hypertensive crisis.
Abrupt cessation of administration following prolonged high dosage results in extreme fatigue and depression. Because of the effect on the central nervous system phendimetrazine tartrate may impair the ability of the patient to engage in potentially hazardous activities such as operating machinery or driving a motor vehicle; the patient should therefore be cautioned accordingly.
Caution is to be exercised in prescribing phendimetrazine for patients with even mild hypertension.
Insulin requirements in diabetes mellitus may be altered in association with the use of phendimetrazine and the concomitant dietary regimen.
Phendimetrazine may decrease the hypotensive effect of guanethidine.
The least amount feasible should be prescribed or dispensed at one time in order to minimize the possibility of overdosage.
Usage in Pregnancy – Safe use in pregnancy has not been established. Until more information is available, phendimetrazine tartrate should not be taken by women who are or may become pregnant unless, in the opinion of the physician, the potential benefits outweigh the possible hazards.
Usage in Children – Phendimetrazine tartrate is not recommended for use in children under 12 years of age.