Melatonin is a naturally occurring hormone produced by the pineal gland that coordinates circadian rhythms and regulates sleep/wake cycles. It also has well-documented anti-tumor effects. In many different tumor cell lines, melatonin inhibits cell division, promotes differentiation, and in some cases, even induces apoptosis. Some papers claim that melatonin suppresses invasiveness and thereby decreases the likelihood of cancer metastasis. It also supposedly increases sleep quality and has positive effects on the immune system, all of which are attractive properties for any cancer patient. It is commonly used as an adjuvant to decrease negative side effects of chemotherapy. My path-breakers for beating brain cancer, Cheryl Broyles and Ben Williams, both take 10 mg of melatonin daily, and a number of clinical trials have been conducted on the anti-tumor effects of melatonin, with doses ranging from 10-20 mg daily.
This seemed like a good addition to my anti-cancer regimen. So, I went to the local Walgreens and bought the most credible-looking melatonin pills I could find. I was aiming for a dose of 15 mg daily, but I started with 5 mg with plans to ramp upwards gradually. In retrospect, I can’t justify my confidence, but since I had read dozens of papers on melatonin, I assumed that I would tolerate it without any difficulties. I was very much mistaken. The next day, after one dose, I was groggy and light-headed the entire morning. Jing tells me I was irritable as well. Light-headedness is an unpleasant feeling if you don’t have complete confidence in your neurological fitness, or if you’ve recently had a stay in a rehab hospital. It felt like a big step backwards; hence my (justifiable) irritability. Jing, the rational physician, assured me it must be the melatonin — the only new chemical introduced that week — rather than something worrisome. So I discontinued it. Oddly, the light-headedness and sleepiness persisted for days afterwards, although it did progressively improve toward the end of the week. This particularly was vexing to me, since the half-life of melatonin in plasma really ought to be less than an hour, unless the circadian field has seriously misjudged things. I spoke with a few colleagues who use melatonin routinely, and one (of about the same build as me) typically uses a dose of 250 micrograms nightly (40X less than what I was taking at max). He insists that doses greater than 1 mg leave him groggy for hours after waking, which was reassuring. My other colleague uses 0.5 to 1.0 mg nightly with no problems. So, I thought I really ought to be able to tolerate the much lower doses, and still hopefully derive some anti-tumor benefits. Wrong again. 250 micrograms left me feeling like over-cooked asparagus the next day. No good to man or beast. I needed 2 cups of strong tea and a brisk mile-long walk before I felt like my normal, crispy self.
This is all very unsettling, because I have lots of things to do in order to fight vigorously against this illness, and it simply won’t do to spend my days in a mental haze. I’ve done that before, and it’s not much fun. So why does everyone tolerate melatonin better than me? The best theory I have is that it’s interacting in some interesting way with the Keppra that I’m taking, which also caused sleepiness and mental sedation for quite a while until I acclimated. I’ve done a few casual Google searches to see if anyone has reported on interactions between Keppra and melatonin, and I don’t see it documented anywhere. So I’m putting it on (electronic) paper for the betterment of the human race. In case others notice synergies between Keppra and melatonin, you’re not alone. I have no idea about the underlying mechanism, but perhaps some enterprising pharmacologist could learn something interesting about one or both drugs by figuring out what’s going on.
In terms of melatonin’s anti-cancer properties, Jing tells me that I need to just have some faith that I’m doing enough as is. More on that topic tomorrow.
UPDATE: July 15, 2015
After careful consideration, I think it’s more likely that melatonin interacts with Ganoderma, not Keppra.