Ah, I did not know that one! But I have a patient for whom that information will be of extreme interest; thanks for sharing.
+1
“Go off of food”? 
Cold turkey??
I’m surprised you didn’t know this; topirimate is actually used in combination with a stimulant (I don’t remember the name) in a prescription weight loss medication called Adipex. The weight loss effects of Topamax (topirimate) are fairly well known.
I agree with those saying that early satiety and losing weight without trying are legitimately concerning symptoms which deserve a workup. While there are definitely other possible explanations, it is true that such symptoms can sometimes be the first signs of cancer, unfortunately, especially in an older person.
In hindsight, my family realized that my own mother’s first inkling that something was wrong when she developed terminal ovarian cancer was that she had started to lose weight without trying. It turned out that the reason she was no longer hungry was because her intestines were being encased by malignant cells. Unfortunately, I was just a med student time who had not yet learned that unexplained weight loss is a big deal in older people. If I had known then what I know now, I would have definitely made sure she went to a doctor much sooner.
If I were you, I would definitely get in to see your PCP, explain that you’re very worried about what this weight loss means since you haven’t been trying to lose weight, ask him to explain to you what workup he’s done for this and what the test results mean. If he has no explanation for what is causing these symptoms then I’d probably try to get in to see a gastroenterologist as the next step. At the very least, if you haven’t had a colonoscopy lately and have a family history of colon cancer, I think a GI doc would likely want to scope you.
I apologize for all my shortcomings.
Weight loss medication is not commonly prescribed in my patient population. I’ve never seen it on a medication list, in fact.
It’s anti-epilepsy drug, commonly used for Migraines (which is what I use it for), however, it’s also used, off-label (kinda), for weight loss.
No need for snark, I was simply surprised.
Yes, I’ve got someone just put on it for seizures, and she’s been complaining that everything tastes funny. I’ve let her doctor know, but they didn’t give me any new orders. Now that I know that, I can tell her it might be the culprit. 
I don’t know about the taste thing (common as it is) since I never had it, but some of the side effects (speficailly pins and needles) will go away, at least to a point. I still get them once in a while.
Once she’s ramped up to the full dosage, it’s probably (IIRC) about 6 weeks for paresthesia to die down to a manageable level or at least a level where you can decide if the pros of the drug outweigh the cons.
It’ll come back each time the doctor bumps the dosage up as well. Also, for me, it’s worse in winter.
Topamax also can have the side effect of causing difficulty thinking and understanding (relatively) complex concepts, earning it the nickname “Dopamax”. Just an FYI.
Just to clear up a miscommunication WRT weight loss medication:
Adipex=phentermine (NOT a combination medication)
Topamax=topiramate
Qsymia=phentermine/topiramate
Qsymia was developed because it was noted that patients on topiramate were losing weight and it was thought that combining it with a stimulant weight loss medication would boost this effect. Since the first two are generic and Qsymia is very expensive, it is often more cost effective to prescribe the generics although Qsymia has a lower dose of topiramate than is otherwise available.
In terms of unexpected weight loss-I agree that you need an evaluation. Make sure you get your thyroid checked and that you are up to date on routine cancer screenings. While most people tend to think that cancers cause weight loss despite eating well, loss of appetite can be a sign of a malignancy (particularly pancreatic cancer) as well as other disease.
Yep. Hie thee to a doctor. Demand tests.
I’ve shed a substantial amount of weight in the last 18 months, and every physician I’ve seen (and I’ve been to several specialists for various things) has immediately inquired as to whether my weight loss has been intentional.
Ahh yes, it’s Qsymia. I had it a bit mixed up. I just knew that topirimate is used in a stimulant/combination medication.
It could be from a thyroid imbalance , did you have this checked out?
Well if you do a little googling there is a lot of results about topamax causing hyperthyroidism so maybe it is the medication.
When this happened to my mother she found out it was likely due to untreated diabetes. She had blood taken many, many times because she had congestive heart failure but I guess nobody ever thought to check for that.
Indeed; that’s what caused my sudden weight loss.
Diabetes check was my first thought, hyperthyroid my second. Please keep pestering doctors and let us know how it’s going for you.
My family has thyroid issues. My brother and cousin have both had this issue. My brother’s weight went lower than it was when he was a skinny 16-year-old before they got it under control.
Do you have copies of all your bloodwork and other reports?
Without knowing the OP’s weight before and current, it’s hard to say.
Losing 75 pounds over a few years is no cause for concern really, unless you wound up very thin at the end.
Even 13 pounds over a month’s time isn’t extreme. Dieters are told to lose 2.5 pounds a week and not more than 5 pounds per week. So that puts you well within the acceptable range for dieting weight loss.
Sometimes you just get sick of food. For instance, I never was a big meat eater and for about five years I lost all interest in eating meat and didn’t eat any. I have no disagreement against eating meat, but it didn’t appeal to me. Then one day I wanted a hamburger so I ate it.
Today I don’t eat much meat just every so often, when I feel like it.
Unless your weight is going down to dangerous levels for your weight/height ratio, it’s hard to say.
Did you read the OP? He’s not dieting. He specifically stated that “it hasn’t been any part of a plan or deliberate acts.”