Phentermine HCl Capsules are a prescription medication used as a short-term aid in weight loss for individuals with obesity. Phentermine is classified as a sympathomimetic amine and functions as an appetite suppressant, helping individuals reduce caloric intake and manage weight in cases where obesity poses significant health risks. It is intended for short-term use due to its stimulant-like properties.

Phentermine stimulates the central nervous system by promoting the release of norepinephrine in the brain. This action activates the “fight or flight” response, leading to appetite suppression and increased energy expenditure. It may also have minor effects on dopamine and serotonin pathways, contributing further to appetite control. The drug’s anorectic effect supports weight loss by reducing hunger and helping patients adhere to dietary restrictions.

Phentermine is contraindicated in individuals with a history of cardiovascular disease, hyperthyroidism, glaucoma, agitated states, or a history of drug abuse. It should not be used in patients currently taking monoamine oxidase inhibitors (MAOIs) or within 14 days of MAOI therapy. Caution is advised in individuals with hypertension, diabetes, or psychiatric disorders. Due to its stimulant nature, phentermine has a potential for dependency and should be used under strict medical supervision.

Phentermine may interact with a range of medications, including MAO inhibitors, which can cause hypertensive crises if taken concurrently. Its combination with other weight-loss medications, such as fenfluramine or dexfenfluramine, has been associated with serious cardiovascular complications and is strongly discouraged. Caution is also advised when combining phentermine with insulin or oral hypoglycemics, as weight loss may alter glycemic control. The use of alcohol or other stimulants can amplify side effects such as nervousness or elevated blood pressure.

Common side effects include dry mouth, insomnia, increased heart rate, elevated blood pressure, nervousness, and constipation. Some patients may also experience dizziness, mood changes, or restlessness. In rare cases, more serious effects such as chest pain, palpitations, or shortness of breath may occur and require immediate medical attention. Due to its stimulating properties, abrupt discontinuation may lead to withdrawal symptoms in some individuals.

Phentermine is not recommended during pregnancy due to the risk of fetal harm and lack of safety data. Weight loss is not advised during pregnancy, even in individuals with obesity, as it may negatively impact fetal development. The presence of phentermine in breast milk is not well established; however, due to its potential to cause adverse effects in nursing infants, breastfeeding while using this medication is not advised. A healthcare provider should be consulted before use during pregnancy or lactation.

Store this medication at 68°F to 77°F (20°C to 25°C) and away from heat, moisture and light. Keep all medicine out of the reach of children. Throw away any unused medicine after the beyond-use date. Do not flush unused medications or pour down a sink or drain.

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