Anorectic Weight Loss Drugs
Posted 04-22-2008 at 03:34 PM by szo
The words anorectic or anorexigenics, commonly used for anti-obesity drugs, mean anorexia or lack of appetite. They come from the Greek words an, meaning “not”, and orexi, meaning “appetite”.
Anorectic drugs or agents are used for the purpose of diminishing the appetite for overweight individuals with or without medical risk conditions. These drugs speed up the Central Nervous System (CNS), producing amphetamine-like effects, but are generally less potent. They all have sympathomemetic activity, which means, they produce effects like CNS and cardiovascular excitation. They are all controlled substances because of the similarity of their effects to those of the amphetamines.
The anti-obesity preparations that act at the Central Nervous System are:
- Phentermine (Ionamin, Fastin, Adipex, Lonamin, Duromine) - It is indicated as a short term treatment to individuals who have medical risks due to their weight. It works by stimulating the brain to release some chemicals that control appetite. Its actions result to increased blood pressure and heart rate, restlessness, insomnia, tremor, and headache, therefore individuals who have mild to moderate hypertension should take precautions when taking this drug. Maintenance dose is 15-30mg 1 capsule daily after breakfast to 12years old an above.
- Diethylpropion (Tenuate, Tepanil) - It’s also called Diethylpropion and Amfepramone. It has a stimulant effect on the Central Nervous System which increases the blood pressure. It has been found to be potentially neurotoxic that it causes long-term depletions of 5-HT, a receptor that acts in CNS which controls behaviour like feeding, sleep, and thermoregulation. It is manufactured in 25mg tablets and 75mg controlled-release tablets.
- Sibutramine (Meridia, Reductil) - It’s indicated for patients with BMI of equal to or greater than 30kg/sqm or with BMI of equal to or greater than 27kg/sqm who have obesity related risk factors like type2 diabetes or dyslipidemia. Dosage is 10mg once daily initially and may be increased to 15mg daily. Duration of treatment should be 1 year maximum. It is contraindicated to patients with psychiatric conditions like bulimia or anorexia nervosa, serious depressions; hypertension, hyperthyroidism, impaired kidney and liver function; children below 18 or elderly, and pregnant women or lactating. Loss of appetite, constipation, insomnia, hypertension, dizziness, or taste disturbances may be experienced by patients.
- Rimonabant (Acomplia, Riobant, Slimona, Rimoslim, Zimulti) - It is a CB1 receptor antagonist which suppresses appetite as a result. It is given to individuals with BMI greater than 30kg and with medical risk conditions, together with an exercise program and low calorie diet. FDA approval is still pending.
- Orlistat (Xenical) - It is used for long term treatment of obesity to patients with risk factors such as high cholesterol, hypertension, or type 2 diabetes mellitus. It should not be given to persons below 18 years, pregnant women, or lactating. Increased defecation may be experienced with fatty or oily stool. It should not be taken with drugs that are fat soluble as it inhibits their absorption.
The following are appetite depressants:
- Benfluorex - It is an anorectic and lipid-lowering drug (hypolipidemic). It also shows to improve diabetes management and decreases insulin resistance.
- Diethylcathione. the same as Diethylpropion
- FG 7142 - It is an anorectic that works as a partial benzodiazepine receptor antagonist.
- Norpseudoephedrine (Cathine) - A monoamine alkaloid found in the shrub Catha edulis (khat). The Convention on Psychotropic Substances classified Cathine as a Schedule III drug, and as a Schedule IV controlled substance in the United States.
- Phenylpropanolamine (PPA) - It is used as a decongestant and as an appetite suppressant. In the US, prescription is needed to avail this drug due to increased risk of stroke in younger women.
- Phenmetrazine - It’s a stimulant of the CNS indicated as an anorectic. The trade name Preludin was replaced by the weaker analogue Phendimetrazine (Bontril) after it was removed in the market. Other replacements are Defenmetrazin, Fenmetrazin, Phenmetraline, and Oxazimedrine.
- Pyroglutamyl-histidyl-glycine - is an anorectic.
- Phendimetrazine (Bontril, Prelu-2, Plegine, Obex) - It is indicated as a treatment for obesity. Its actions include CNS stimulation and elevation of blood pressure. Caution should be made with patients with mild hypertension. Allergic reactions, including bronchial asthma, may be experienced. It should not be given to children 12 years and below, to patients with a history of drug abuse, or to patients taking CNS stimulants including monoamine oxidase inhibitors.
- Benzphetamine (Didrex) - It is an anti obesity drug that the main function is to reduce hunger, therefore reduces caloric intake. It should not be given to patients with advanced arteriosclerosis, moderate to severe hypertension, cardiovascular disease, glaucoma, and who are in agitated state or who have a history of drug abuse.
- Oxyntomodulin - It suppresses appetite and can be used as a weight loss treatment. It is not well understood how it works but it is known as naturally occurring 37 amino acid peptide hormone found in the colon.
- Methylphenidate (Ritalin, Concerta) - It stimulates the CNS, reducing impulsive behaviour, and helps on work concentration. It has been reported that it increased the ability of adults with ADHD to focus on tasks and organize their lives.
- Fenfluramine (Pondimin) - It is a part of the Fen-Phen anti-obesity drug (the other part is Phentermine). It causes the release of the neurotransmitter serotonin, a chemical that regulates mood, appetite, and other functions. It reverses serotonin transporter function which results to a feeling of fullness. In 1997, this drug was withdrawn from the US market after reports of heart disease conditions and pulmonary hypertension.
- Mazindol (Sanorex, Mazanor) - It is a CNS stimulant used as short term treatment to exogenous obesity. It is indicated as adjunct to a weight reduction program in patients with body mass index of 30kg/sqm or those with medical risk factors such as hypertension, diabetes, or hyperlipidemia.
The amount of weight loss associated with the use of an anorectic drug varies from trial to trial. Patients taking this drug should be warned of the tolerance to the anorectic effect which usually develops within a few weeks. When this occurs, the recommended dose should not be increased in an attempt to feel the effect but instead, the medication should be discontinued.
Anorectic drugs or agents are used for the purpose of diminishing the appetite for overweight individuals with or without medical risk conditions. These drugs speed up the Central Nervous System (CNS), producing amphetamine-like effects, but are generally less potent. They all have sympathomemetic activity, which means, they produce effects like CNS and cardiovascular excitation. They are all controlled substances because of the similarity of their effects to those of the amphetamines.
The anti-obesity preparations that act at the Central Nervous System are:
- Phentermine (Ionamin, Fastin, Adipex, Lonamin, Duromine) - It is indicated as a short term treatment to individuals who have medical risks due to their weight. It works by stimulating the brain to release some chemicals that control appetite. Its actions result to increased blood pressure and heart rate, restlessness, insomnia, tremor, and headache, therefore individuals who have mild to moderate hypertension should take precautions when taking this drug. Maintenance dose is 15-30mg 1 capsule daily after breakfast to 12years old an above.
- Diethylpropion (Tenuate, Tepanil) - It’s also called Diethylpropion and Amfepramone. It has a stimulant effect on the Central Nervous System which increases the blood pressure. It has been found to be potentially neurotoxic that it causes long-term depletions of 5-HT, a receptor that acts in CNS which controls behaviour like feeding, sleep, and thermoregulation. It is manufactured in 25mg tablets and 75mg controlled-release tablets.
- Sibutramine (Meridia, Reductil) - It’s indicated for patients with BMI of equal to or greater than 30kg/sqm or with BMI of equal to or greater than 27kg/sqm who have obesity related risk factors like type2 diabetes or dyslipidemia. Dosage is 10mg once daily initially and may be increased to 15mg daily. Duration of treatment should be 1 year maximum. It is contraindicated to patients with psychiatric conditions like bulimia or anorexia nervosa, serious depressions; hypertension, hyperthyroidism, impaired kidney and liver function; children below 18 or elderly, and pregnant women or lactating. Loss of appetite, constipation, insomnia, hypertension, dizziness, or taste disturbances may be experienced by patients.
- Rimonabant (Acomplia, Riobant, Slimona, Rimoslim, Zimulti) - It is a CB1 receptor antagonist which suppresses appetite as a result. It is given to individuals with BMI greater than 30kg and with medical risk conditions, together with an exercise program and low calorie diet. FDA approval is still pending.
- Orlistat (Xenical) - It is used for long term treatment of obesity to patients with risk factors such as high cholesterol, hypertension, or type 2 diabetes mellitus. It should not be given to persons below 18 years, pregnant women, or lactating. Increased defecation may be experienced with fatty or oily stool. It should not be taken with drugs that are fat soluble as it inhibits their absorption.
The following are appetite depressants:
- Benfluorex - It is an anorectic and lipid-lowering drug (hypolipidemic). It also shows to improve diabetes management and decreases insulin resistance.
- Diethylcathione. the same as Diethylpropion
- FG 7142 - It is an anorectic that works as a partial benzodiazepine receptor antagonist.
- Norpseudoephedrine (Cathine) - A monoamine alkaloid found in the shrub Catha edulis (khat). The Convention on Psychotropic Substances classified Cathine as a Schedule III drug, and as a Schedule IV controlled substance in the United States.
- Phenylpropanolamine (PPA) - It is used as a decongestant and as an appetite suppressant. In the US, prescription is needed to avail this drug due to increased risk of stroke in younger women.
- Phenmetrazine - It’s a stimulant of the CNS indicated as an anorectic. The trade name Preludin was replaced by the weaker analogue Phendimetrazine (Bontril) after it was removed in the market. Other replacements are Defenmetrazin, Fenmetrazin, Phenmetraline, and Oxazimedrine.
- Pyroglutamyl-histidyl-glycine - is an anorectic.
- Phendimetrazine (Bontril, Prelu-2, Plegine, Obex) - It is indicated as a treatment for obesity. Its actions include CNS stimulation and elevation of blood pressure. Caution should be made with patients with mild hypertension. Allergic reactions, including bronchial asthma, may be experienced. It should not be given to children 12 years and below, to patients with a history of drug abuse, or to patients taking CNS stimulants including monoamine oxidase inhibitors.
- Benzphetamine (Didrex) - It is an anti obesity drug that the main function is to reduce hunger, therefore reduces caloric intake. It should not be given to patients with advanced arteriosclerosis, moderate to severe hypertension, cardiovascular disease, glaucoma, and who are in agitated state or who have a history of drug abuse.
- Oxyntomodulin - It suppresses appetite and can be used as a weight loss treatment. It is not well understood how it works but it is known as naturally occurring 37 amino acid peptide hormone found in the colon.
- Methylphenidate (Ritalin, Concerta) - It stimulates the CNS, reducing impulsive behaviour, and helps on work concentration. It has been reported that it increased the ability of adults with ADHD to focus on tasks and organize their lives.
- Fenfluramine (Pondimin) - It is a part of the Fen-Phen anti-obesity drug (the other part is Phentermine). It causes the release of the neurotransmitter serotonin, a chemical that regulates mood, appetite, and other functions. It reverses serotonin transporter function which results to a feeling of fullness. In 1997, this drug was withdrawn from the US market after reports of heart disease conditions and pulmonary hypertension.
- Mazindol (Sanorex, Mazanor) - It is a CNS stimulant used as short term treatment to exogenous obesity. It is indicated as adjunct to a weight reduction program in patients with body mass index of 30kg/sqm or those with medical risk factors such as hypertension, diabetes, or hyperlipidemia.
The amount of weight loss associated with the use of an anorectic drug varies from trial to trial. Patients taking this drug should be warned of the tolerance to the anorectic effect which usually develops within a few weeks. When this occurs, the recommended dose should not be increased in an attempt to feel the effect but instead, the medication should be discontinued.
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