Active ingredient: Phentermine - Brands, Medical Use, Clinical Data

Brands, Medical Use, Clinical Data

Drug Category

• Adrenergic Agents
• Appetite Depressants
• Central Nervous System Agents
• Anorexigenic Agents
• Stimulants

Dosage Forms

• Capsule (30 mg)

Brands / Synonyms

(alpha,alpha)-Dimethylphenethylamine; Adipex-P; Duromine; Fastin; Inoamin; Ionamin; Linyl; Lipopill; Lonamin; Mirapront; Normephentermine; Obenix; Obestin-30; Oby-Trim; Omnibex; Ona Mast; Ona-Mast; Phentercot; Phentermine Hcl; Phentermine Hydrochloride; Phentermine Resin 30; Phentride; Pre-Sate; Pro-Fast; Qsymia; Suprenza; Teramine; Tora; Uritone; Wilpo; Wyamine Sulfate; Zantryl

Indications

For the treatment and management of obesity.

Pharmacology

Phentermine is indicated in the management of exogenous obesity as a short term (a few weeks) adjunct in a regimen of weight reduction based on caloric restriction. Phentermine hydrochloride is a sympathomimetic amine with pharmacologic activity similar to the prototype drugs of this class used in obesity, the amphetamines. Actions include central nervous system stimulation and elevation of blood pressure. Tachyphylaxis and tolerance have been demonstrated with all drugs of this class in which these phenomena have been looked for.

Mechanism of Action

Phentermine is an amphetamine that stimulates neurons to release or maintain high levels of a particular group of neurotransmitters known as catecholamines; these include dopamine and norepinephrine. High levels of these catecholamines tend to suppress hunger signals and appetite. Phentermine (through catecholamine elevation) may also indirectly affect leptin levels in the brain. It is theorized that phentermine can raise levels of leptin which signal satiety. It is also theorized that increased levels of the catecholamines are partially responsible for halting another chemical messenger known as neuropeptide Y. This peptide initiates eating, decreases energy expenditure, and increases fat storage.

Absorption

Phentermine is rapidly absorbed after oral ingestion.

Toxicity

LD₅₀ is adult monkeys is 15 to 20 mg/kg. Symptoms of overdose include delirium, mania, self-injury, marked hypertension, tachycardia, arrhythmia, hyperpyrexia, convulsion, coma, and circulatory collapse.

Biotrnasformation / Drug Metabolism

Hepatic.

Contraindications

Advanced arteriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension, hyperthyroidism, known hypersensitivity, or idiosyncrasy to the sympathomimetic amines, glaucoma.

Agitated states.

Patients with a history of drug abuse.

During or within 14 days following the administration of monoamine oxidase inhibitors (hypertensive crises may result).

Drug Interactions

Concomitant use of alcohol with phentermine hydrochloride may result in an adverse drug interaction.