Phentermine is a stimulant similar to an amphetamine. It acts as an appetite suppressant for influencing the central nervous system.
Phentermine is not for overweight people and is especially recommended for those with a body weight of over 300 pounds.
It is used along with diet and exercise to treat obesity (overweight) in people with risk factors such as hypertension, high cholesterol or diabetes.
It is a prescription medication and should not be used without a doctor’s consent.
Mechanism of action:
It is an appetite suppressant in the middle of the hypothalamus, and the adrenal glands stimulate norepinephrine release. This neurotransmitter signals a flight or flight response and reduces hunger. It also acts peripherally to break down stored fat. The most important mechanism, however, is to reduce need. Phentermine also causes the release of dopamine and serotonin, but much less than norepinephrine.
Side effects of Phentermine:
It can cause side effects like
- Dry mouth
- Unpleasant taste
- Threw up
Some side effects can have serious consequences
- Elevation of blood pressure
- Chest pain
- Swelling of the legs and ankles
- If you have difficulty exercising, you could do
Phentermine is not a good option if you have heart disease, hyperthyroidism, glaucoma, or high blood pressure.
It is not safe if you are pregnant, pregnant, or breastfeeding. It is important to note that it should not be combined with other drugs for weight loss.
Do not use Phentermine if you have a monoamine oxidase in the last 14 days (MAO) have taken. A dangerous interaction could occur. MAO inhibitors include Isocarboxazid, linezolid, phenelzine, Rasagiline, Selegiline, and tranylcypromine.
Phentermine Precautions and Warnings
Phentermine is a prescription medication commonly used to assist with weight loss by suppressing appetite. While it can be effective for some individuals, several necessary precautions and warnings must be considered before starting this medication. Understanding these factors is crucial to ensure the safe and appropriate use of Phentermine. Here are some key points to keep in mind:
- Medical History Evaluation: Before starting Phentermine, you must provide your healthcare provider with a comprehensive medical history. Inform them about any existing medical conditions, including heart problems, high blood pressure, diabetes, thyroid issues, history of drug abuse, or mental health disorders. These conditions influence the safety and effectiveness of Phentermine in your case.
- Contraindications: Certain medical conditions may contraindicate the use of Phentermine. This means that using the medication could pose serious risks. Contraindications can include a history of heart disease, uncontrolled high blood pressure, hyperthyroidism, glaucoma, and drug abuse. If these conditions apply to you, your healthcare provider might recommend an alternative weight loss approach.
- Drug Interactions: Phentermine can interact with other medications, potentially causing adverse effects or reducing the effectiveness of either medication. Inform your doctor about all your medicines, supplements, and herbal products to ensure no potentially harmful interactions.
- Cardiovascular Risk: Phentermine can increase heart rate and blood pressure, which may concern individuals with pre-existing heart conditions. Regular monitoring of blood pressure and heart rate is recommended while taking Phentermine. If you experience chest pain, shortness of breath, or any concerning heart-related symptoms, seek medical attention immediately.
- Central Nervous System Stimulation: Phentermine acts as a stimulant, affecting the central nervous system. This can lead to side effects such as restlessness, insomnia, anxiety, and irritability. Individuals with a history of anxiety or other mental health disorders should be cautious when using Phentermine, as it might exacerbate these conditions.
- Pregnancy and Breastfeeding: Phentermine is generally not recommended during pregnancy or breastfeeding. Its safety for the developing fetus or the nursing infant has not been well established. Discuss alternative weight loss options with your healthcare provider if you are pregnant, planning to become pregnant, or breastfeeding.
- Tolerance and Dependence: Phentermine has the potential to become habit-forming if used for prolonged periods. Tolerance to the medication may also develop, leading to reduced effectiveness over time. Follow your healthcare provider’s prescribed dosing instructions carefully to prevent dependence and ensure optimal results.
- Withdrawal Effects: Abruptly discontinuing Phentermine after prolonged use can lead to withdrawal symptoms such as fatigue, depression, and mood changes. To avoid these issues, your healthcare provider will likely guide tapering off the medication when it’s time to stop.
- Age Considerations: Phentermine is typically prescribed for adults. Its safety and effectiveness in children and adolescents have yet to be well established, so a healthcare professional should carefully evaluate and monitor its use in these populations.
Remember, Phentermine is just one component of a comprehensive weight loss plan that should include a balanced diet and regular physical activity. To make an informed decision about using Phentermine, have an open and thorough discussion with your healthcare provider, considering your medical history, current health status, and potential risks. Your safety and well-being are paramount.
Dosage of Phentermine:
The recommended dose is 15-37.5 mg once a day.
Phentermine is administered approximately 1-2 hours after breakfast.
The lowest effective dose should be used, and the evening doses should be avoided as It causes insomnia.
Phentermine Drug Interactions
Like many medications, Phentermine can interact with other drugs, potentially affecting their effectiveness or increasing the risk of adverse effects. Before starting Phentermine, it’s crucial to inform your healthcare provider about all the medications, supplements, and herbal products you’re taking. Here are some notable drug interactions to be aware of:
- Monoamine Oxidase Inhibitors (MAOIs): Phentermine should not be taken concurrently with MAOIs or within 14 days of discontinuing MAOI therapy. Combining Phentermine and MAOIs can lead to a potentially life-threatening condition called serotonin syndrome, characterized by symptoms like high fever, agitation, rapid heartbeat, and increased blood pressure.
- Selective Serotonin Reuptake Inhibitors (SSRIs): There is a potential for interactions between Phentermine and SSRIs, a class of antidepressants. Combining these drugs may increase the risk of serotonin syndrome. If your doctor prescribes both medications, they will closely monitor you for any adverse effects.
- Serotonergic Medications: Beyond MAOIs and SSRIs, other medications that affect serotonin levels, such as certain antidepressants and migraine medications (e.g., triptans), could interact with Phentermine and result in serotonin syndrome. Close medical supervision is necessary if these combinations are prescribed.
- Other Stimulants: Combining Phentermine with other stimulant medications, like caffeine, decongestants, or amphetamines, can amplify the stimulant effects and increase the risk of cardiovascular side effects like increased heart rate and high blood pressure.
- Antihypertensive Medications: Phentermine can raise blood pressure and heart rate, so combining it with antihypertensive drugs might counteract the desired effects of both medications. Adjustments in dosage or careful monitoring might be required.
- Guanethidine: Phentermine’s stimulant effects can counteract the blood pressure-lowering effects of guanethidine, potentially reducing its effectiveness.
- Insulin and Oral Diabetes Medications: Phentermine might affect blood sugar levels and insulin sensitivity. People with diabetes taking insulin or oral diabetes medications should have their blood sugar levels closely monitored when starting Phentermine, and adjustments to their diabetes treatment plan may be needed. We have discussed Insulin in detail in this article.
- Antidepressants and Antipsychotics: Certain medications used to treat depression and mental health disorders can interact with Phentermine, affecting its effectiveness or causing adverse effects. Always consult your doctor if you’re taking these medications alongside Phentermine.
- CYP2D6 Inhibitors: Phentermine is metabolized by the CYP2D6 enzyme. Drugs that inhibit this enzyme (e.g., certain antidepressants, antipsychotics, and antiarrhythmics) could potentially increase the levels of Phentermine in the body, leading to an increased risk of side effects.
- Herbal Supplements and Over-the-counter Drugs: Even herbal products and medications can interact with Phentermine. St. John’s Wort, for instance, is known to interact with many medicines, including Phentermine.
You can learn more about medicine and supplements at DrugsBank.