The Athlete

Benzphetamine (Didrex)

Benzphetamine is an anorectic drug in a similar class as amphetamines (speed). It stimulates the central nervous system, causing rapid heartbeat and an increase in blood pressure. This drug should only be taken for a short time by those who are extremely obese, and only under strict supervision of your doctor.

This drug is widely available over the internet, but I would strongly caution anyone taking it without a doctor's recommendation. The long and short-term side effects can be extremely damaging. The risk factors must be carefully weighed before this drug is prescribed.

Side Effects

Cardiovascular: Palpitation (a strong heartbeat that you can feel), tachycardia (very rapid heartbeat), elevation of blood pressure.

Central Nervous System: overstimulation, restlessness, dizziness, insomnia (sleeplessness), tremor (shaking), headache, psychotic state, agitation (excessive restlessness), flushing, sweating, blurring of vision.

Gastrointestinal: Dryness of the mouth, diarrhea, constipation, nausea, stomach pain.

Genitourinary: Urinary frequency, dysuria (painful urination), changes in libido - this drug acts differently with everyone. Some find their sexual desire is increased tremendously, while others lose all desire.

Allergic:Hives and skin rashes

Abuse and Dependence

Benzphetamine is classified as a Schedule III controlled substance. This means it has a high potential for abuse and addiction. Benzphetamine is related chemically and pharmacologically to the amphetamines. Amphetamines and related stimulant drugs have been extensively abused and many are now illegal.
Abuse of amphetamines and related drugs may be associated with intense psychological dependence and severe social dysfunction. There are, reports of patients who have increased the dosage to many times that recommended.

This drug must be used short-term only because long-term use can lead to psychosis, which is often clinically indistinguishable from schizophrenia.

Stopping the drug abruptly after high dosage administration, results in extreme fatigue and mental depression, as well as changes in sleep.


Tolerance is the body's ability to adjust to the drug and to need higher doses to achieve the same effect. 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.


Benzphetamine should not be taken if:
* You have even mild hypertension (high blood pressure)
* You have coronary artery disease
* You have arteriosclerosis (hardening of the arteries)
* You have asthma or any respiratory problems
* You have an allergy or sensitivity to aspirin
* You have glaucoma
* You have hyperthyroidism (over active thyroid)
* You are taking any other stimulants
* You have kidney problems
* You have a history of drug abuse
* You are normally a nervous or easily agitated person


Acute overdosage may manifest itself by the following signs and symptoms: unusual restlessness, confusion, belligerence, hallucinations and panic states. Fatigue and depression usually follow the central nervous system stimulation. Cardiovascular effects include arrhythmias, hypertension (high blood pressure), or hypotension (low blood pressure) and circulatory (blood vessels) collapse. Gastrointestinal symptoms include nausea, vomiting, diarrhea and abdominal cramps. High fever or kidney failure may result. Poisoning may result in convulsions, coma and death

Pregnancy and Nursing Mothers

Didrex may cause fetal harm when administered to a pregnant woman, and should not be used by women who are or may become pregnant. It is also excreted into breast milk and women taking Didrex should stop nursing.

Usage in Children

Children under 12 should not take Benzphetamine.

Geriatric Use

Clinical studies of Didrex did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, caution should be used in elderly patients due to the greater frequency of kidney, liver and heart problems.

Recommended Dosage

25 - 50 mg one to three times daily. Treatment should begin with 25mg once a day and increased only according to response. A single daily dose is preferably given in mid-morning or mid-afternoon, according to the patient's eating habits. Some may find a dose later in the day will cause insomnia (sleeplessness).

When properly used Benzphetamine can help the grossly obese lose weight, however it is a potent drug and shouldn't be used if you just have a few pounds to lose. As with all prescription weight loss drugs, have your doctor monitor your progress and should you experience any problems contact your doctor and stop the drug.

Information for the informed athlete:

Weight loss and other weight loss drugs

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