Didrex Tablets contain the anorectic agent benzphetamine hydrochloride.
Benzphetamine is an anti-obesity drug marketed under brand name: Didrex in the USA by Pharmacia.

Benzphetamine has been approved by the FDA in 1960, for treating obesity on a short term use.

Benzphetamine is a sympathomimetic amine, which is similar to an amphetamine. It is also known as an “anorectic” or “anorexigenic” drug.
Didrex works by suppressing your appetite .

Although the mechanism of action of the sympathomimetic appetite suppressants in the treatment of obesity is not fully known, these medications have pharmacological effects similar to those of amphetamines. Amphetamine and related sympathomimetic medications (such as benzphetamine) are thought to stimulate the release of norepinephrine and/or dopamine from storage sites in nerve terminals in the lateral hypothalamic feeding center, thereby producing a decrease in appetite. This release is mediated by the binding of benzphetamine to centrally located adrenergic receptors. Tachyphylaxis and tolerance have been demonstrated with all drugs of this class in which these phenomena have been looked for.

Benzphetamine is contraindicated in patients with advanced arteriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension, hyper-thyroidism, known hypersensitivity or idiosyncrasy to sympathomimetic amines, and glaucoma. Benzphetamine should not be given to patients who are in an agitated state or who have a history of drug abuse.

Benzphetamine hydrochloride is a white crystalline powder readily soluble in water and 95% ethanol.
Each Didrex tablet, for oral administration, contains 50 mg of benzphetamine hydrochloride.
Inactive Ingredients: Calcium Stearate, Corn Starch. Ervthrosine Sodium. FD 8 C Yellow No.61 Lactose, Povidone, Sorbitol.
Didrex tablets are supplied as follows:

50 mg (peach, round, imprinted with Didrex 50, scored)

  • Bottles of 100 NDC 0009-0024-01
  • Bottles of 500 NDC 0009-0024-02

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make.
It is best to take Didrex in the mid-morning or mid-afternoon. Because Didrex may cause sleeplessness, do not take a dose late in the day unless directed to do so by your doctor.
Carefully follow your doctor’s instructions about a special diet plan that will help you lose weight .
For weight loss:
Dosage should be individualized according to the response of the patient. The suggested dosage ranges from 25 to 50 mg one to three times daily. Treatment should begin with 25 to 50 mg once daily with subsequent increase in individual dose or frequency according to response. A single daily dose is preferably given in mid-morning or mid-afternoon, according to the patient’s eating habits. In an occasional patient it may be desirable to avoid late afternoon administration. Use of benzphetamine hydrochloride is not recom-mended in children under 12 years of age.

It is very important that your doctor check your progress at regular visits to make sure that Didrex is working properly .

Didrex may be habit-forming. If you feel that the medicine is not working as well, do not use more than your prescribed dose. Call your doctor for instructions .

If you will be taking Didrex for a long time, do not stop taking it without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping completely .

Check with your doctor right away if you think that you may be pregnant. Benzphetamine may cause birth defects or other problems in the baby if taken during pregnancy. Use an effective form of birth control to keep from getting pregnant .

You should not use Didrex if you have used an MAO inhibitor (MAOI) such as Eldepryl, Marplan, Nardil, or Parnate within the past 14 days .

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines, and herbal or vitamin supplements .

Didrex may cause some people to feel a false sense of well-being or to become dizzy, lightheaded, or less alert than they are normally. Make sure you know how you react to Didrex before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.

Didrex is available only with your doctor’s prescription .

Appetite suppressants are not a substitute for proper diet. For maximum effects, this must be used in combination with diet and exercise programs.