It is about Respect
It is something that we take for granted, something we do not think about.
But even an over the counter medication can be deadly when abused.

Tylenol says in its commercials:
Stop.
Think.

for a reason. Daily I hear and see people take much more than the recommended dose. They do the same with medications like Advil and wonder why they are nursing a bleeding ulcer.

The recommended dose of Tylenol is two pills. Just two. No more. Less if possible.
Acetaminophen. It is the active ingredient. You can overdose, and this overdose is slow, and sometimes fatal.
What causes it?
It damages your liver, and as much of a beating as your liver can take, when too much assaults it, it will give up, and you sort of need your liver to you know, live. Hell, it is in the name.

How can you prevent overdose?
Read the labels; follow the directions.
This goes for over the counter and Rx's.
Look for interactions. This means talking to your doctor, and looking at the active ingredients in the medications you take.
Tylenol provides a list (though not entirely complete) of common medications that contain acetaminophen and therefore should not be combined with Tylenol.
Read up here

Also see information on Tylenol and NSAIDs as found in Advil, Motrin, and Aleve.

On Sleeping Pills
Over the counter sleeping pills generally contain an antihistamine such as diphenhydramine hydrochloride or doxylamine succinate.
Yes, antihistamines. They are depressants, which is why when you take a med for allergies you get tired.
So what do you think you should not take with them?
Oh! Yeah allergy medications.
ON top of that!
BY NO MEANS, NO MEANS, should you EVER mix OC and Rx! This means your Xanax and your Valium and of course never mix either of those with alcohol!
Yeah, so guys, stressed out, can't sleep? Don’t wash down your TylenolPM with your night cap and Vicodin.
Oh yeah, Vicodin, contains Tylenol.
Oh! Aspirin is not so innocent either. Acute overdose has a mortality rate of2%, but chronic ODing on it--low level over dose over a long period of time--25%.

Why am I going over this?
Because Heath Ledger died, and I am betting it turns out not to be a suicide, but an accidental overdose. He is not the first, and unfortunately, he will not be the last.
Look, I take a disgusting amount of pills a day, and yes, they interact, and conflict and you know, I feel like I am gambling every time I take a dose.
But I'm aware, and I forgo what I can, when I can.
I'm aware because I read the literature provided with each and every Rx, and the warnings and directions on every over the counter medication.
And most importantly:
I follow them.

Talk to your doctor, always before taking anything with your Rx's. Even herbals .
especially herbs
There are several that are literally aspirin, and many that cause toxicity if you take them.
Hell--Grapefruit!.
I can't have it. It blocks the metabolism of one of my medications and causes it to build up in my system, and on the dose I'm on, the backup will become toxic quickly.
If by some odd chance I want a drink. I don't take two of my medications, and I limit what I have severely because my remaining meds still interact with it and they depress my system anyway.

Assessment and Moderation
The last thing you can do is assess your pain or your sleep issue accurately and decide what you can safely take, and take as little as possible.
Only a slight headache? Skip the pills, get a heating pad instead, or a cup of soothing lavender tea.
Restless before bed? Try reading a book, or doing some stretching, or breathing exercises.
Sore? Take a hot bath or shower and stretch it out.
Toothache? GO TO YOUR DENTIST (and rinse with salt water--trust me!)
Use medications, all medications, as a last resort and with the utmost respect. Mild pain? There are ways around it without those little compressed pieces of chalk.
Try not to live out of a bottle. They are not the answer to everything, and it gets old, real fast.
Trust me.
Stop.
Think.
Educate yourself

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_{**Disclaimer: I am by no means advocating a position that would have you forgo all medication all the time. Moderate use of OTC drugs is by no means something to look down on. Take the medicines your doctor prescribes, and the way he instructs you to. They did not get a medical degree for nothing folks.}