Adipex-PR (phentermine hydrochloride)
Phentermine hydrochloride is a sympathomimetic stimulant of the amphetamine family. Like other amphetamine derivatives, it is categorized as an anorectic (appetite suppressing) agent. Phentermine is commonly prescribed as a weight loss aid in obese patients. It is typically used for short periods of time (less than 12 weeks), and as an adjunct to support an ongoing exercise and dieting regimen. The main focus is to curb the desire to eat, thereby reducing the total caloric intake. Although the data seems to vary from trial to trial, much of it supports at least a modest additional loss of fat mass with the use of phentermine hydrochloride.1 Athletes and bodybuilders use phentermine hydrochloride for the same purpose, typically when weight loss is required for physique remodeling or competition.
Phentermine hydrochloride was first introduced to the U.S. drug market in the 1970s. Base phentermine was available in the U.S. as far back as 1959. Phentermine had long been used as an appetite suppressant, although the most notable attention to it came in the early 1990s, when the drug was successfully paired with fenfluramine during diet studies. Investigators had shown that this type of drug combination was actually more effective at promoting weight loss than diet and exercise, results that quickly catapulted Fen-Phen into top place in the prescription weight loss drug market. By 1997, however, it had become apparent that a very high percentage of Fen-Phen users were noticing heart valve defects as a result of the drugs. Fenfluramine was identified as the principle cause, and was withdrawn from the U.S. market that same year. Phentermine remains available in the U.S. and many nations abroad today. Popular trade names include Adipex, lonamin, Anoxine, Phentrol, and Obenix. Note that as an amphetamine derivative, this medication has a tendency to be habit forming. For this reason it has been added to the U.S. controlled substances list as a schedule IV medication.
Phentermine hydrochloride is most commonly supplied in tablets and capsules of 18.75 mg and 37.5 mg each.
Phentermine hydrochloride is a central stimulant and indirectacting sympathomimetic of the amphetamine family. It has the chemical designation 2-methyl-1 phenylpropan-2-amine (2methyl-amphetamine).
Common side effects associated with phentermine hydrochloride include insomnia, increased blood pressure, irritability, nervousness, and euphoria. Less common side effects include vision disturbances, reduced libido, confusion, diarrhea, dizziness, dry mouth, headache, irregular heartbeat, nausea, vomiting, rash, and tiredness. Phentermine is a CNS stimulant with potential for fatal overdose. Signs of overdose may include rapid breathing, fever, hallucinations, blood pressure irregularities, irregular | heartbeat, unconsciousness, trembling, shaking, panic, extreme restlessness, and severe nausea, vomiting, or diarrhea.
For optimal effectiveness, phentermine hydrochloride should not be taken with food. The usual adult dose is one capsule or tablet (37.5 mg) daily, administered before or 12 hours after breakfast. For some patients a half of a tablet (18.75 mg) daily may be adequate, while in other cases it may be advisable to give a half of a tablet (18.75 mg) twice daily. When taken more than once per day, the second dose should never be taken within 4-6 hours of sleep. The drug is typically used for 3-4 weeks at a time, with longer durations of therapy rarely exceeding 12 weeks. Bodybuilders and athletes typically use the prescribed amount of drug in a similar short-term fashion, due to the high likelihood of side effects as the dose escalates beyond the normal therapeutic range.
Phentermine hydrochloride is available in a number of different countries. It is not widely counterfeited. U.S. residents would not be advised to order the drug from overseas, however, since phentermine is a schedule IV controlled substance and carries similar legal restrictions as Valium and anabolic steroids.
Many U.S. doctors who specialize in weight loss medications will readily dispense phentermine for controlled periods of weight loss
1 A double-blind clinical trial in weight control. Use of fenfluramine and phentermine alone and in combination. Weintraub M, Hasday JD, Mushlin AI, Lockwood DH.Arch Intern Med. 1984 Jun;144(6):1143-8