Surveys and findings on the after effects and interactions of Didrex have revealed that this drug, primarily prescribed for controlling obesity and weight reduction should not be administered concomitantly with CNS stimulants. For example the use of amphetamines decrease the hypotensive effect of antihypertensiveness. In addition, the use of amphetamines has the tendency to increase the effects of tricyclic antidepressants.

In similar context, overdose of Didrex drug is severely advised against as this has shown to result in symptoms of restlessness, tremor, tachypnea, confusion, and assaultiveness and panic states. Fatigue and depression usually follow the central stimulation. Overdose has also shown adverse affects on various conditions of cardiovascular ailments including arrhythmias, hypertension or hypotension, and circulatory collapse. For those with gastric problems, Didrex overdose has resulted in symptoms of nausea, vomiting, diarrhea, and abdominal cramps.

The administration or intake of Didrex is also advised against in-patients suffering from advanced arteriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension, hyper-thyroids, known hypersensitivity or idiosyncrasy to sympathomimetic amines, and glaucoma. In addition, patients suffering from a history of drug abuse or those with agitated state are also advised against the use of Didrex drug. Pregnant women, as well as those wishing to become pregnant are also advised against the use of Didrex as the drug usage has resulted in harming the fetus.

Some of the precautionary measures advised during or prior to the commencement of Didrex therapy note that the Didrex drug must be used for weight reduction and obesity where other alternative therapies have proven to be ineffective.

This is primarily due to the high risk factors involved in the usage of amphetamines as well as the potentials for abuse of the Didrex drug. Furthermore, the prolonged usage of Didrex has also shown to result in the patient becoming dependant on the drug, hence its inclusion in the Schedule II of Federal Drug Control Regulations.