Aa
Aa
A
A
A
Close
Avatar universal

Phentermine and Levothyroxine

I am a 40 year old female who weighed 125lbs. for the last 10 years. Between May and July I went from 125 to 146. I am now at 151lbs. No change in diet and I joined a gym 3 months ago and have worked out religiously but continue to gain.

The unexplained weight gain is especially in my abdomen, which is very distended. My internist ordered a CT scan and ultrasound to look for fibroids, cysts, etc. Results were one small fibroid.

She also tested my thyroid which revealed a TSH of 4.270 and free T4 of 1.12. Initially, she wanted to just retest in 6 weeks. However, I brought her an article from the AACE that recommends treatment over 3.0. She was receptive to this and agreed to start me on 25mcg. Levothyroxine and retest in 6 weeks.

In addition to the Levo, the exercise, and a healthy diet, I also started taking 30mg. Phentermine to help get this weight off. It's a prescription I had leftover from a couple of years ago. I started both meds 4 days ago.

Questions: Do you believe that a TSH of 4.270 could explain my rapid weight gain of 25lbs in 3 months? My internist cannot find anything else wrong with me, except for the one submucosal fibroid. Is 25mcg a high enough dose to effect any real change in my TSH? Is taking the Phentermine at the same time as the Levo okay to do? My doctor does not know I'm doing this. Also, since starting these two meds 4 days ago I haven't felt very well; kind of spacey and fatigued. Any opinion about that?

My doctor said depending on what my TSH shows in 6 weeks, she may order an MRI to look at my pituitary gland and possibly refer me to an endo. Thank you for your time.
3 Responses
Sort by: Helpful Oldest Newest
Avatar universal
This from wikipedia:

"Because phentermine acts through sympathomimetic pathways, the drug may increase blood pressure and heart rate. It may also cause palpitations, restlessness, and insomnia. Additionally, phentermine has the potential to cause physical and psychological dependence."

If you are overmedicated with thryoid meds, you can become hyperthyroid, which does not seem like a good combination with phentermine (the symptoms for hyperthyroid are almost identical--heart palps, insomnia...).  Talk to doctor, please! You might be able to try the phentermine once your TSH level is lowered.

Helpful - 0
Avatar universal
I would let your doctor know about the Phentermine. I'm not familiar with the drug and its interactions, but better safe than sorry!
Helpful - 0
Avatar universal
Ooops....I meant to post this in Dr. Lupo's forum. But if anyone here has any info for me, I'm all ears. Thanks!
Helpful - 0
Have an Answer?

You are reading content posted in the Thyroid Disorders Community

Top Thyroid Answerers
649848 tn?1534633700
FL
Avatar universal
MI
1756321 tn?1547095325
Queensland, Australia
Learn About Top Answerers
Didn't find the answer you were looking for?
Ask a question
Popular Resources
We tapped the CDC for information on what you need to know about radiation exposure
Endocrinologist Mark Lupo, MD, answers 10 questions about thyroid disorders and how to treat them
A list of national and international resources and hotlines to help connect you to needed health and medical services.
Herpes sores blister, then burst, scab and heal.
Herpes spreads by oral, vaginal and anal sex.
STIs are the most common cause of genital sores.