This article is one in a series on Medications for Pain… what are your choices? how do various medications work? what are the pros and cons? how about side effects? (Discuss these ideas with your doctor. Don’t make any changes to your treatment by yourself.)
The medication we’ll look at today is Ketamine, an anesthetic. Anesthetics are drugs which prevent sensations, particularly pain. Ketamine is an “NMDA-receptor antagonist”. Also in this class is Dextromethorophan (which is an active ingredient in cough syrup). These medications can be used:
- Topically (through the skin)
- By mouth in pill form
- Intravenous (IV) low-dose infusion
- Intravenous (IV) at high doses – “ketamine coma”
Effect of Ketamine:
Ketamine and others in this class are called NMDA-receptor antagonists. This means they block nerve conduction at a specific (NMDA) neurotransmitter site.
Uses of Ketamine:
Ketamine is only approved as an anesthetic for surgical procedures, not for chronic pain. In chronic pain treatment, it’s used on the skin for nerve pain, and by IV for CRPS (Complex Regional Pain Syndrome or RSD). The concentration of Dextromethorophan in cough syrup is very low. When used for chronic pain, it’s given in concentrated pill form.
Side Effects:
Ketamine’s short term side-effects include anxiety and hallucinations. There’s been concern over unknown longer-term consequences, including cognitive (memory) problems. However, a recent study showed no decrease in attention, learning, and memory in 9 patients with CRPS who underwent Ketamine coma. However, we’re still at an early stage in learning how to use Ketamine more safely for chronic pain.
Also Interesting:
Ketamine’s other uses include in veterinary medicine, battlefield medicine, and as a recreational drug. You might also be interested in these articles about Ketamine Coma and CRPS.
Next Monday, we’ll look at Muscle Relaxants. Other articles in this series:
4 responses so far ↓
Jordan Lund // Oct 29, 2007 at 3:14 am
My painkiller of choice is Ketoprofin. It’s hard to find now since it’s OTC brand Orudis was taken off the market.
OTC strength was 12.5 mg, prescription versions which are still available come in 25, 50, 100 and 200 mg versions.
I have chronic joint pain in my knees and ketoprofin is the only thing that works for me.
How to Cope with Pain // Oct 29, 2007 at 7:22 am
Jordan, thanks for your comment. As you know, Ketoprofen is an anti-inflammatory medication. Just so others are aware, it has a similar name to Ketamine, but it’s a different class of medication. You might also want to check out the article in this series on anti-inflammatories.
Terry at Counting Sheep // Oct 30, 2007 at 7:11 pm
Actually, in the anesthesia world, ketamine produces dissociative anesthesia. In layman terms, it temporarily scrambles your brain, and induces intense analgesia. It can produce hallucinations and delirium, and should be administered with a benzodiazepine like midazolam, which is an anxiolytic.
How to Cope with Pain // Oct 31, 2007 at 7:46 am
Terry has an interesting blog - a nurse anesthetist, who writes about her field. And she’s right - use of short-term Ketamine for surgury is different from use in chronic pain.
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