From the Guidelines
It is recommended to obtain a baseline EKG before starting phentermine for weight loss, especially in patients with a history of cardiovascular disease or uncontrolled hypertension, as phentermine can increase heart rate and blood pressure. Phentermine is a sympathomimetic amine that stimulates the central nervous system, and its use can be associated with adverse cardiovascular effects, such as palpitations and increased blood pressure 1. A baseline EKG can help identify any pre-existing cardiac abnormalities that might increase the risk of these adverse effects.
According to the most recent guidelines, phentermine should be used with caution in patients with a history of cardiovascular disease or uncontrolled hypertension, and it is generally recommended to avoid its use in these patients 1. The standard dosing of phentermine is typically 15-37.5 mg once daily, taken in the morning to avoid insomnia. During treatment, regular monitoring of blood pressure, heart rate, and any cardiac symptoms is important. If a patient develops chest pain, palpitations, fainting, or shortness of breath while on phentermine, they should seek immediate medical attention and discontinue the medication.
Some key points to consider when prescribing phentermine include:
- The medication should be used short-term (usually up to 12 weeks) as part of a comprehensive weight management program that includes diet and exercise 1
- Phentermine should not be used in patients treated with, or within 14 days of, monoamine oxidase inhibitors, or in patients with untreated hyperthyroidism 1
- Commonly reported adverse effects include constipation, dry mouth, palpitations, insomnia, and irritability 1
- Patients who have anxiety or insomnia might feel their condition is exacerbated by phentermine, and would not be ideal candidates 1
From the Research
Phentermine and Baseline EKG
- There is no direct evidence in the provided studies that suggests a baseline EKG is necessary before starting someone on phentermine for weight loss 2, 3, 4, 5, 6.
- The studies focus on the effects of phentermine on blood pressure, heart rate, and weight loss, as well as its safety and effectiveness for weight management 2, 3, 5.
- One study discusses the importance of considering cardiovascular risk when using phentermine and other weight-loss drugs, but it does not specifically mention the need for a baseline EKG 4.
- Another study examines the cardiovascular safety of phentermine and topiramate, but it does not address the issue of baseline EKGs 6.
Cardiovascular Monitoring
- Some studies suggest that monitoring blood pressure and heart rate is important when using phentermine, as it can affect these parameters 2, 5.
- However, the studies do not provide clear guidance on whether a baseline EKG is necessary before starting phentermine therapy.
- It is possible that a baseline EKG may be recommended in certain situations, such as in patients with pre-existing heart conditions, but this is not explicitly stated in the provided studies.