I feel the experience over the weekend is worth outlining as it involves someone, myself, who thought they knew what they were doing yet had quite a close call.
A word of background about myself. Plenty of people have more experience of substances than do I but I would not consider myself a novice by now. For quite some time I've been a near daily user, altering use and combinations according to inclination and circumstance, primarily using crystal meth, crack cocaine, cocaine, GHB, and, most of all, mephedrone. Meth I limit to avoid addiction and have smoked roughly a dozen and a half times before.
The day in question, I began smoking at 2pm and stopped at about 7pm when difficulties began (I had smoked until 10am the night before). First mistake: I was attempting to finish what was on hand, but I didn't believe it amounted to much more than I'd taken often enough before without problems. Second mistake: I hadn't made allowance for the unusually high purity of the batch in question, which I'd been advised about, and had confirmed in the days before when I tested it. Third mistake: I had grown complacent with meth and didn't monitor myself while smoking as carefully as I used to do.
Around 7pm it quite suddenly became obvious that something was not right. Within what seemed like only a few moments, a strong high turned into something different and I noticed that my body was in difficulty. The intensity of the physical experience grew and grew from here on. My whole body seemed to be struggling and churning and although I managed to stand up every time I tried to do so it required focus and concentration. I took 1ml of ghb in the hope of calming the system and another an hour later but there was enough methamphetamine in play that the ghb had no discernible effect whatsoever and on advice I gave up that strategy, which may be inadvisable in any case.
I would struggle to describe the physical intensity of a meth overdose but it is not another type of high or an experience anyone would wish to know. About two hours after I had stopped smoking, the signs of approaching cardiac arrest became impossible to ignore. My heart was palpably out of control and between 160-190 bpm. The claminess arrived. My breath had been shortening since problems became obvious but was now quite difficult. Nausea. Dizziness. And most of all waves of chest pain. I was talking to the moderator of this forum at the time, fortunately, who advised in frank terms medical assistance and I called an ambulance despite extreme reluctance to do so.
Before the ambulance arrived, and it did take a certain amount of time, I reached a level of physical distress I hadn't ever imagined possible, with a degree of chest pain and the other symptoms that made me believe that I was either having a heart attack or on the very edge of having one. I made several further emergency calls during these minutes and after a sudden explosion of fire-like pain throughout my chest believed that I would die before help reached me. Paramedics arrived, ran an ecg, and then prepared for cardiac arrest during transit to hospital with the defilibrator on standby. At emergency, drugs were administered by iv to stabilise the heart, and not too long after this happened, heartrate fell under 150, and after four hours of observation I was allowed to discharge myself, although it was still between 100-120 bpm. I've been quite lucky as doctors were surprised that no lasting heart damage had occured, as can of course happen even without cardiac arrest.
The doctor was reluctant later to specify how close I came to cardiac arrest but I was treated until stabilised on the basis that it was possible at any moment. Once the necessary medicine was administered, I came out of the danger zone quite quickly. The two days since have been unpleasant if non-serious but only an idiot complains after getting himself into an overdose.
Two things I would suggest people try to take on board:
1. Don't believe the folk wisdom that you can't OD smoking meth. I wasn't new to it and did so without even initially noticing
2. If told to get medical help, do, immediately. If in physical distress, certainly with the warning signs of cardiac arrest, do so immediately.
A last word: not calling the ambulance when I did - on advice here - could have delayed medical attention beyond the point at which it could still be any use. I'm glad to be here still and I would suggest that people be aware of the importance of getting potentially life-saving treatment if overdosing, as not everyone who tries to ride it out is still here to write it up.