Weight Loss Drugs (cont.)
Louise Chang, MD
Dr. Chang completed her undergraduate degree at Stanford University and attended medical school at New York Medical College. She completed her internal medicine residency at Saint Vincent's Hospital in New York City, where she also served as a chief resident from 2001-2002. Dr. Chang is board-certified in internal medicine.
In this Article
- What are weight loss drugs and how do they work?
- Who is a good candidate for weight loss drugs?
- What are the different types of weight loss drugs?
- What are the side effects of weight loss drugs?
- What are the warnings with weight loss drugs?
- What are the drug interactions with weight loss drugs?
- What are some examples of weight loss drugs?
- What are OTC diet pills?
- What do I need to know about OTC diet supplements?
- Here are some common ingredients seen in OTC diet supplements:
What are the warnings with weight loss drugs?
Before starting any medication, let your doctor know your full medical history such as drug allergies, medical conditions, current medication use, and whether you are pregnant, trying to become pregnant, or nursing.
Because patients can develop tolerance to this type of prescription diet pill within weeks, they are indicated for short-term use.
Using this type of weight loss medication may also result in drug dependence and abuse. Side effects seen with chronic use include irritability, personality changes, insomnia, even psychosis similar to schizophrenia. Sudden withdrawal may result in severe depression.
Operating a motor vehicle or machinery may be more difficult while using these weight loss drugs. People with heart disease, high blood pressure, thyroid problems, glaucoma, or epilepsy may not be able to take these medications.
Phentermine (Adipex-P, Fastin)
Pulmonary hypertension is a rare and potentially fatal blood vessel disease of the lungs that has reportedly occurred when the amphetamine-like drug phentermine was used in combination with two now-withdrawn weight loss products: dexfenfluramine (Redux) and fenfluramine (Pondimin). Rarely, it has occurred in those taking phentermine alone. Symptoms include trouble breathing, chest pain, fainting, and edema.
Similarly, regurgitant cardiac valvular disease, or a leaky heart valve, has been linked to phentermine use in combination with dexfenfluramine and fenfluramine, but this effect possibly could occur from phentermine use alone.
People who are already taking medications or have medical conditions such as high blood pressure and diabetes need to talk to their doctor about risks of taking phentermine.
High doses may result in hallucinations; toxic psychosis is also possible with excessive or even proper use.
Diethylpropion may increase the risk of convulsions in epileptics.
Sibutramine can substantially raise blood pressure and/or pulse rate in some patients. Because of this, sibutramine users should have their blood pressure and pulse rate monitored regularly. The drug should be used with caution, if at all, in patients with a previous history of hypertension, stroke, heart disease, or severe kidney or liver disease.
Patients with narrow angle glaucoma should not use sibutramine because it causes dilation of the pupils (mydriasis). Sibutramine may interact with other medications, so it is important to talk to a doctor about current medications before starting sibutramine.
Orlistat (Xenical, Alli)
High-fat diets or meals may increase side effects from orlistat. Orlistat inhibits absorption of fat-soluble vitamins. Patients should take a multivitamin containing fat-soluble vitamins with two hours' separation from the orlistat dose.
Orlistat may increase the risk of gallbladder and kidney stones. People taking medications for diabetes, thyroid disorders, or other medical problems should talk to their doctor about possible drug interactions before taking orlistat.
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