Ketamine + Gabapentin

[dalek dex]

I have done this combo dozens of times in the past, and I’m considering repeating it, but I just want to make sure I hadn’t been playing with fire. I’ve gone as high as 4,000mg Gabapentin with K-hole doses. Even at doses that high, the only negative side effect I experienced was nausea.

I know that both are CNS depressants, and mixing CNS depressants is a big no-no, but is it true that Gabapentin does not suppress breathing? If Gabapentin truly does not affect breathing, would this be a safe combination? I have a moderate Gabapentin tolerance, if that matters.

 

[VanWeyden]

I've never sone this combo and there isn't much clinical expertise about this afaik, but you shouldn't have a problem combining Gabapentin and Ketamine. Neither of them have any respiratory or circulatory-depressing properties. On the contrary, they both can cause a slight increase in breathing rate and circulation.

 

[pasha]

I have done this combo dozens of times in the past, and I’m considering repeating it, but I just want to make sure I hadn’t been playing with fire. I’ve gone as high as 4,000mg Gabapentin with K-hole doses. Even at doses that high, the only negative side effect I experienced was nausea.

I know that both are CNS depressants, and mixing CNS depressants is a big no-no, but is it true that Gabapentin does not suppress breathing? If Gabapentin truly does not affect breathing, would this be a safe combination? I have a moderate Gabapentin tolerance, if that matters.

Even though I don't recommend you take such a high dose of gabapentin with ketamine, I'm intrigued. Why do you do it? Is there some synergy? If so can you describe it in detail?

Here are my findings:

ketamine ↔ pregabalin
Applies to:ketamine and Lyrica (pregabalin)
MONITOR: Central nervous system- and/or respiratory-depressant effects may be additively or synergistically increased in patients taking multiple drugs that cause these effects, especially in elderly or debilitated patients.


MANAGEMENT: During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. Ambulatory patients should be counseled to avoid hazardous activities requiring mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

Case study:

Possible gabapentin and ketamine interaction causing prolonged central nervous system depression during post-operative recovery following cervical laminoplasty: a case report

http://www.jmedicalcasereports.com/content/5/1/167

Case study:

Together, gabapentin and ketamine could have con- tributed to the prolonged recovery. An online source relates that these drugs used together may have a syner- gistic effect and that the patient should be monitored for prolonged CNS and respiratory depression [6]. Sev- eral studies have shown how the use of ketamine with other CNS depressants can potentiate CNS depression

http://www.biomedcentral.com/content/pdf/1752-1947-5-167.pdf

I've never sone this combo and there isn't much clinical expertise about this afaik, but you shouldn't have a problem combining Gabapentin and Ketamine. Neither of them have any respiratory or circulatory-depressing properties. On the contrary, they both can cause a slight increase in breathing rate and circulation.

^If you've never done it and there are no clinical studies, on what basis can you say he shouldn't have a problem?

 

[dalek dex]

I've never sone this combo and there isn't much clinical expertise about this afaik, but you shouldn't have a problem combining Gabapentin and Ketamine. Neither of them have any respiratory or circulatory-depressing properties. On the contrary, they both can cause a slight increase in breathing rate and circulation.

That is interesting. I was not aware that neither has any respiratory or circulatory-depressing properties. Do you have a source confirming this? I would like to learn more about this.

Even though I don't recommend you take such a high dose of gabapentin with ketamine, I'm intrigued. Why do you do it? Is there some synergy? If so can you describe it in detail?

Taking 4,000mg Gabapentin was a one-time thing, which I would never recommend either. Typically, I would stay between 2,400mg and 3,200mg Gabapentin with 3 or 4 lines of K (which is still a bit high, but I'd already been taking Gabapentin for a few years).

The synergy between these two drugs is amazing. I have found that Gabapentin greatly amplifies Ketamine's effects. The euphoria and visuals (both OEVs and CEVs) are much more intense. Also, sometimes Ketamine gives the feeling of being on a slow moving roller coaster (for me at least), and Gabapentin makes this effect much more pronounced. Falling asleep is also made much easier. I have enough trouble falling asleep as it is, and Ketamine makes my insomnia worse.

I have read the case study regarding a patient experiencing prolonged CNS depression from this combo, but I did not think too much into it. The study only considers a single patient, and the patient may have experienced an adverse reaction from something else.

 

[pasha]

The synergy between these two drugs is amazing. I have found that Gabapentin greatly amplifies Ketamine's effects. The euphoria and visuals (both OEVs and CEVs) are much more intense. Also, sometimes Ketamine gives the feeling of being on a slow moving roller coaster (for me at least), and Gabapentin makes this effect much more pronounced. Falling asleep is also made much easier. I have enough trouble falling asleep as it is, and Ketamine makes my insomnia worse.

That's fascinating, I do a lot of ketamine, and I also have access to pregabalin, one may assume that it could have the same synergistic effects that you and one of my above studies mentions.

 

[paranoid android]

Well I'm prescribed 3200mg's of gabapentin a day and i have taken ketamine with about 800mg's of gabapentin in the past. I never found it to affect the high but it can cause more drowsiness though as some people pointed out i don't think gabapentin causes respiratory depression. However i wouldn't take high doses of gabapentin with ketamine as ketamine is so nice on it's own that i don't want to fuck up the high with the shitty feeling of taking too much gabapentin.

 

[bronson]

I just want to make sure I hadn’t been playing with fire. I’ve gone as high as 4,000mg Gabapentin with K-hole doses. Even at doses that high, the only negative side effect I experienced was nausea.

I know that both are CNS depressants, and mixing CNS depressants is a big no-no, but is it true that Gabapentin does not suppress breathing? If Gabapentin truly does not affect breathing, would this be a safe combination? I have a moderate Gabapentin tolerance, if that matters.

Gabapentin is a CNS depressent, just to a lesser extent than many other substances are. However when combined with other stronger CNS depressants a cumulative effect occurs. Just because you haven't had a bad experience with the combo thus far doesn't mean that it isn't a possibility. This is usually how overdoses eventually happen.

If you do continue with this the most important thing to bear in mind is your tollerance is going to rise, but you aren't going to be able to increase your doses of the two in order to keep up. Doing that would elevate the risk drastically.

Stay safe and all the best,
-bronson

 

[VanWeyden]

Even though I don't recommend you take such a high dose of gabapentin with ketamine, I'm intrigued. Why do you do it? Is there some synergy? If so can you describe it in detail?

Here are my findings:



Case study:




http://www.jmedicalcasereports.com/content/5/1/167

Case study:



http://www.biomedcentral.com/content/pdf/1752-1947-5-167.pdf




^If you've never done it and there are no clinical studies, on what basis can you say he shouldn't have a problem?

Neither of these drugs cause any type of respiratory or circulatory depression on their own. Ketamine can cause apnea in some cases, but only when dosed above 2,5mg/kg i.v., which no recreational user would ever do. Their pharmacological profiles do not suggest serious interactions, theoretically speaking.

When I said "there isn't much clinical expertise" I meant that this combination isn't as well studied as other recreationally used drugs, for example opiates and benzodiazepines, tramadol & stimulants or alcohol & barbiturates. There are studies on that combination, neither of them discovered additional serious side effects:

http://www.ncbi.nlm.nih.gov/pubmed/20495588
http://www.ncbi.nlm.nih.gov/pubmed/19734790

The case study you quoted twice is hardly significant - firstly the patient is afflicted with several comorbidities, secondly he is regularly prescribed 14 different meds, thirdly the incident happened after surgery with general anesthesia which adds five more drugs (midazolam, succinylcholine, propofol, fentanyl, ketamine) to the list. The paralysis might be an effect of gabapentin and ketamine, it might as well be an interaction of some of the other 17 drugs as well as symptomatic transitory psychotic syndrome, conversion disorder or whatever. Concluding that the combo is dangerous with this case report as only argument is a bit arbitrary, isn't it?

 

[VanWeyden]

That is interesting. I was not aware that neither has any respiratory or circulatory-depressing properties. Do you have a source confirming this? I would like to learn more about this.

The sympathomimetic effects of ketamine are well-established. That's the reason for it being a major anaesthetic in emergency medicine - when a patient is already in circulatory shock you may hesitate to use the "traditional" an aesthetics which tend to lower circulation even more. Respiratory depression occurs only when a bolus dose above 2,5mg/kg is administered. You can read this in every anaesthesia or emergency medicine textbook.
Gabapentin has no circulatory effects most of the time, but it is well-known to cause hypertonia as a side effect sometimes. Unfortunately I have no sources in English for that, I'm German and could only give you German Drug Information sheets.

 

[pasha]

^ The point of case studies is for the reader/conductor to draw data, theorize, hypothesize and claim a definite or indefinite conclusion. I merely presented the case study without drawing any conclusions, as opposed to you drawing a conclusion that ketamine and gabapentin possess no deppresant effects.

You claim you have the data to put this thesis to bed but until you can present that in fact, ketamine alone and/or in combination with gabapentin has no central depressive effects than I cannot draw a definite conclusion, making it safe to recommend that in the interest of harm reduction the combination should not be executed. You contradict yourself by saying there are no definitive clinical studies, than advising that the combination can be practiced safely.

Neither of these drugs cause any type of respiratory or circulatory depression on their own.

^This has not been fully established especially in respects to ketamine.

Effects on respiratory system
Ketamine is a mild respiratory depressant. It causes a shift of the CO2 dose-response curve to the right, in a dose-related manner, but does not change the slope of the curve. Respiratory drive to CO2 may be depressed as much as 15 to 22%. This effect is similar to that of opioids, but dissimilar from most sedative hypnotics and anaesthetics, suggesting that opioid receptors may play a role in the respiratory depressant effect. In clinical studies, the effects were observed only at high doses. Some case reports describe respiratory depression after rapid intravenous injection, but also after routine paediatric use of ketamine administered intramuscularly (Reich and Silvay, 1989; White and Ryan, 1996). At recreational doses respiratory depression is not likely to occur, but cannot wholly be excluded.

http://www.who.int/medicines/areas/quality_safety/4.3KetamineCritReview.pdf

Ketamine is not used as an anesthetic due to the absence of central effects, but more so because in can induce coma and anesthesia in patients in shock, purely because it is effective at doing such.

Your right only in saying that current studies are not definitive, with some claiming insignificant depressant effects, others claiming moderate, some claiming stimulant and bronchodilatory effects and also many claiming that ketamine in combination with a GABA agonist does cause significant depressant effects. None however have claimed no depressant/stimlant effects on ventilation and nervous system, at least from what i've reviewed.

Again if you have definitive data to dispute those claims i'd be more than grateful if you can pass that knowledge along (in English).

 

[dalek dex]

Thank you everyone for your input. Just to be safe, I probably won't be repeating this combination. If I do decide to try this again, I will stick to low doses of both drugs.

 

[nuke]

This combination is incredibly good at low doses of both. 450mg gabapentin (2 h stagger) and 40mg ketamine over 1.5 h is just all around great. The paranoia and anxiogenic effects of the ketamine are gone and it's turned into almost pure fun. Very recreational. No idea how safe it is, but the body seems okay and there are less side effects than with ketamine alone.

 

[downfallin]

That sounds like a combo that I would like hehe. No Idea how safe it is but gabapentin I don`t think decreases breathing all that much.