19 August 2009

More sting connoisseurship

Here's a nice little interview vignette with Justin Schmidt whose 'Justin O. Schmidt's 'Sting Pain Index' I've mentioned before.

On reflection, it is quite funny how much power a drop of venom gives a little tiny bug over us:

Oh, Sting, Where Is Thy Death? - Happy Days Blog - NYTimes.com: The pain index came into being, he said, because he wanted to understand the two ways stinging can be of defensive value to an insect. ‘One is that it can actually do serious damage, to kill the target or make it impaired. The other is the whammy, the pain.’ He could quantify the amount of venom injected and its toxicity, but he had no way to measure pain other than through direct experience. So the pain index gave him a tool for interpreting an insect’s overall defensive strategy.

In fact, most insect stings do no damage at all, except to the two percent of people who suffer an allergic reaction. They just scare the wits out of us. And this is why they fascinate Schmidt: We typically outweigh any insect tormentor by a million times or more. We can outthink it. ‘And yet it wins,’ said Schmidt, ‘and the evidence that it has won is that people flap their arms, run around screaming, and do all kinds of carrying on.’ It wins ‘by making us hurt far more than any animal that size ought to be able to do. It deceives us into thinking serious damage is being done.’ And that’s generally enough to deliver the insect’s message, which is: Stay away from me and my nest."

At least, its funny when a harvester ant whose sting “felt like somebody was putting a knife in and twisting it” makes the point. Less so, when it comes from sterner teachers
A wasp known in the American Southwest as the “tarantula hawk” made him lie down and scream: “The good news is that by three minutes, it’s gone. If you really use your imagination you can get it to last five.” On the other hand, the sting of a bullet ant in Brazil (4-plus on the pain index) had him “still quivering and screaming from these peristaltic waves of pain” twelve hours later, despite the effects of ice compresses and beer.

Redheads need more drugs


The Pain of Being a Redhead - Well Blog - NYTimes.com:
A growing body of research shows that people with red hair need larger doses of anesthesia and often are resistant to local pain blockers like Novocaine. As a result, redheads tend to be particularly nervous about dental procedures and are twice as likely to avoid going to the dentist as people with other hair colors, according to new research published in The Journal of the American Dental Association.

Researchers believe redheads are more sensitive to pain because of a mutation in a gene that affects hair color. In people with brown, black and blond hair, the gene, for the melanocortin-1 receptor, produces melanin. But a mutation in the MC1R gene results in the production of a substance called pheomelanin that results in red hair and fair skin.

The MC1R gene belongs to a family of receptors that include pain receptors in the brain, and as a result, a mutation in the gene appears to influence the body’s sensitivity to pain. A 2004 study showed that redheads require, on average, about 20 percent more general anesthesia than people with dark hair or blond coloring. And in 2005, researchers found that redheads are more resistant to the effects of local anesthesia, such as the numbing drugs used by dentists.

It's also nice to hear that the research came from taking this sort of common experience seriously, rather than simply dismissing it:
Dr. Daniel I. Sessler, an anesthesiologist and chairman of the department of outcomes research at the Cleveland Clinic, said he began studying hair color after hearing so many colleagues speculate about redheads requiring more anesthesia.

‘The reason we studied redheads in the beginning, it was essentially an urban legend in the anesthesia community saying redheads were difficult to anesthetize,’ Dr. Sessler said. ‘This was so intriguing we went ahead and studied it. Redheads really do require more anesthesia, and by a clinically important amount.’

If I had red hair, I would bring a copy of the paper with me to the dentist/doctor to help them take my needs seriously.*

*Just as I would, for example, show literature on the usefulness of pre-incision lidocaine in lowering post-surgicial pain to my surgeon.

I might also post articles on the problems with using morphine in patients with kidney problems on the wall by an elderly relative's hospital bed.

Methadone prescribers' network

The astonishing recent rise in opioid overdoses (many involving methadone) has finally forced me to agree that our (at least in the US) opioid policies and practices need some revision. Thus this expansion of a program available to buprenorphine prescribers seems welcome.

A New Service For Health Care Providers Who Prescribe Methadone To Treat Chronic Pain Or Opioid Addiction: "
A new service for health care providers prescribing methadone to treat chronic pain or opioid addiction -- the Physician Clinical Support System for Methadone (PCCS-M) -- opens this week with a mechanism to connect prescribers of methadone with experienced clinicians for one-to-one mentoring regarding the use of this medication.

Methadone is an inexpensive opioid medication that has several unique properties that make it particularly well suited to the treatment of chronic pain or opioid addiction, but it also has side effects and the potential for overdose and requires specific information for its proper use.

The new service is one in a number of federally-funded projects that address the need within the nation's health care system to provide safe and effective care of patients with chronic pain and opioid addiction while, at the same time, protecting the public from prescription drug abuse and diversion of medications. Using this new service, prescribers can contact a mentor, a knowledgeable colleague, by phone or e-mail with specific questions about the use of methadone for treating chronic pain or opioid addiction.

Source: American Society of Addiction Medicine "

As a general rule, I think drug policy should (strongly) promote the responsible clinician's ability to prescribe opioids as she sees fit . So, insofar as this sort of program can help stem diversion and accidental overdose, I'd much rather see more of these than more restrictive drug policies.

15 August 2009

Coral for neuropathic pain

Not as cool as sea-snail venom, but still worth filing under 'cool things from the sea'

New Hope Of Relief For Neuropathic Pain: "New Hope Of Relief For Neuropathic Pain

A compound initially isolated from a soft coral (Capnella imbricata) collected at Green Island off Taiwan, could lead scientists to develop a new set of treatments for neuropathic pain - chronic pain that sometimes follows damage to the nervous system.

Recent research suggests inflammation in the nervous system is a major causative factor for this condition. Inflammation activates supporting cells, such as microglia and astrocytes, that surround the nerve cells. These activated cells release compounds called cytokines that can excite nerves carrying pain sensation (nociceptive pathways) and cause the person to experience mildly uncomfortable stimuli as very painful (hyperalgesia), or stimuli that would normally induce no discomfort at all as painful (allodynia). Thus, cold drafts or lightly brushing the skin can produce intense pain, severely affecting the person's quality of life.


Although the chemical they studied, capnellene, was originally isolated in 1974, it is only recently that scientists have started to appreciate its potential. Capnellene is interesting because its structure is very different from pain-relieving drugs currently in use. Initial experiments suggested that it may have pain-relieving properties. Working with Yen-Hsuan Jean MD, PhD and other colleagues, Dr Wen tested capnellene and a second very similar compound, in isolated microglial cells and in experimental models of the condition in rats.

They found that the compounds significantly reduced pain-related activities in isolated microglia, and that these compounds also significantly reversed hyperalgesic behaviour in the experimental rats.