Monday, October 18, 2010

PRESCRIPTION DRUGS

At times medications are needed in our obesogenic society. There are at least 43 different neurotransmittors (serotonin. nor-epinephrine, ghrelin, leptin, neuropeptide-y etc) involved with our gaining and maintaing excess weight in the form of fat. Research conducted at the University of Texas at Austin provides evidence of a vicious cycle created when individuals overeat to compensate for reduced pleasure from food. It appears that obese individuals have fewer pleasure receptors and overeating further down regulates these pleasure receptors. For example food intake is associated with dopamine release. The degree of pleasure derived from eating correlates with the amount of dopamine released. Obese individuals have fewer dopamine (D2) receptors in the brain compared with lean individuals thereby the obese individual may overeat to compensate for this reward deficit.

This year alone the Food and Drug Administration (FDA) has been reviewing three new anti obesity drugs for government approval. Although drugs that seem promising early on sometimes prove ineffective and/or dangerous after they are released into the market.

Amphetamines in the 1960s and 1970s were touted as the answer until they proved to be habit forming. In the mid-1990s the disaster with fen-phen (fenfluramine and phentermine) leading to heart valve disease. Then just a few years ago the FDA denied approval for several new weight-loss drugs because of the potential for suicidal behavior.

Only two drugs to date have been FDA-approved for long-term treatment of obesity yet they are not without concern. Earlier this year the European Union banned one of the compounds, sibutramine (Meridia) after reports of heart attack and stroke and recently the FDA is posturing to take them off our market. The other drug, Orlistat, now sold over the counter in half strength size as Alli, causes gastrointestinal distress and has been associated with liver damage in some patients.

Obesity has a neuropsychiatric component, which creates difficulty in finding the “magic bullet”. Yet there are three new drugs that will target the brain, each in a different manner, facing FDA review. Contrave takes aim at the brain's reward pathway yet bupropion, an ingredient in contrave, has been linked to anxiety and neurological effects. Lorcaserin affects serotonin, which involves many brain processes such as emotion and cardiovascular regulation. In July, an FDA advisory panel narrowly voted against the third drug, Qnexa, due to side effects such as memory problems and other unwanted neurological effects.

Our appetite is controlled by the central nervous system present in the hypothalamus. When food enters our stomach, an enzyme called Cholecystokinin-Pancreozymin (CCK-PZ) is secreted from the pancreas. Presence of food is sensed and a number of complex signals are sent to this control center. The neurons there acknowledge it, then send another signal back to tell the body that our stomach is full. These signals are carried by some of the neurotransmitters mentioned above.

There are medications that work by increasing serotonin or catecholamines, two neurotransmitters (chemicals) in the brain that affect both mood and appetite. This class of medications, used most often for weight loss, is commonly referred to as “appetite suppressants.” The FDA approved them in 1959 and has been the most popular prescription weight loss medications sold in the United States. These medications promote weight loss by helping to suppress appetite, and by increasing the subjective feeling of fullness
The prescription medications prescribed in this class are Generic name Phentermine (trade name: Adipex-P, Fastin, Ionamin), Generic name Phendimetrazine (trade name: Bontril, Plegine) and Generic name Diethylpropion (trade name: Tenuate, Tenuate Dospan). Since many of the medical weight loss clinics use them, they will be discussed in more detail later.

The goal of prescribing weight loss medication is to help the medically at risk obese patient “jump start” their weight loss effort and lose at least 10% or more of their starting body weight. Usually anywhere from 5-22 pounds on average will be expected. When this can be accomplished, it usually leads to a reduction in risk for obesity related illnesses, such as diabetes, high blood pressure and heart disease.

Potential Benefits of Appetite Suppressant Treatment:
Short-term use has been shown to modestly reduce health risks in obese individuals. These medications have shown to lower blood pressure, blood cholesterol, blood fats (triglycerides), and decrease insulin resistance (the body’s ability to utilized blood sugar). There have been recent studies mentioned in the American Society of Bariatric Physician community that long term use of these medications resulted in lasting reductions in health risks and should be looked into further.

Potential Risks of Appetite Suppressant Treatment:
All prescription medications used to treat obesity, with the exception of orlistat, are controlled substances. This means that doctors need to follow rigid guidelines when prescribing them. Although abuse and dependence are not common with non-amphetamine appetite suppressants, caution is still advised, especially for those with a history of drug abuse or addiction.

Side Effects:
Appetite suppressants such as phentermine, phendimetrazine and diethylpropion are chemically similar to amphetamines. Thereby these medications can likewise cause insomnia, restlessness, constipation, excessive thirst, sweating, light-headedness, drowsiness, headache, stuffy nose, nervousness and rapid heart rate. Most of these side effects will decrease within the first week to two weeks.

Development of Tolerance:
Studies of appetite suppressant medications indicate that an individual’s weight tends to level off after four to six months of treatment. Is this due to drug tolerance, or reduced effectiveness of the medication over time? Studies are not clear. Yet experience shows that things can be adjusted to extend that timeframe and give the patient a few extra months, at minimum, to accomplish further weight loss.

When considering taking any anti-obesity drugs there are different ways to get them. For many years now there have been websites offering anti-obesity drugs online by simply filling out a form, giving your credit card and having them mailed to your home. Some of these drugs come from countries that do not stand up to the quality assurance that the United States requires for the safety of the recipient. These are not over-the-counter (OTC) medications and need to be strictly monitored. It is best to entrust your overall health and safety to a licensed physician. It is partially due to the quality assurance that these medications should be obtained from a reliable source who has done their home-work rather than a undependable one.

Fringe Benefits
These drugs in addition to weight loss help with ADD, ADHD, Depression, PMS, and Migraines.

1 comment:

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