Venlafaxine improves primary erythromelalgia

[Guest guest]

Hi,

I believe this is article discusses a pilot study for treatment of

erythromelalgia, which is a condition that some in our group have. It

is also the subject of the Yahoo Groups discussion board called the

Red Hots.

Take care,

Matija

May 15, 2002

By: Cheryl Guttman

Dermatology Times

Venlafaxine improves primary erythromelalgia

New Orleans - Results from an open pilot study indicate venlafaxine

(Effexor), a combined norepinephrine and serotonin reuptake

inhibitor, may be a safe and effective treatment for primary

erythromelalgia, Ali Moiin, M.D., and Sharam S. Yashar, M.D., said at

the annual meeting of the American Academy of Dermatology.

They presented their experience using venlafaxine 37.5 mg BID to

treat 10 subjects. A diagnosis of primary erythromelalgia was

established after investigations to rule out other causes for the

patients' signs and symptoms, and all existing medications being used

for their condition were withdrawn.

At one week after starting treatment with venlafaxine, marked

improvement, in the range of 30 percent to 40 percent, was noted by

the investigators in the severity and extent of skin warmth and

erythema, and the patients reported reduction of symptoms of pain and

burning as well. Further benefit was gained with continued treatment,

and by two months, some patients were rated as improved 80 percent

from baseline.

These favorable responses occurred with minimal side effects. Two

patients developed nausea and one patient discontinued treatment due

to drowsiness. Currently, six patients are being followed on chronic

treatment that ranges from six months to four years in duration and

they are continuing to derive benefit and are very satisfied as well,

said Dr. Moiin, clinical assistant professor of dermatology, Wayne

State University, Detroit, and president, Comprehensive Dermatology

Center, Detroit.

" A variety of medications can be used to treat primary

erythromelalgia, including aspirin, gabapentin, opiates,

benzodiazepines, and amitriptyline. The response to those agents is

variable and importantly, they are associated with significant side

effects. Venlafaxine appears to perform well relative to those

options in terms of efficacy, but it has the advantage of offering a

more favorable safety profile with long-term use, " said Dr. Moiin. " No

conclusions can be drawn from this small, open-label trial, and we

cannot rule out the possibility of a placebo effect. However, based

on venlafaxine's promising potential for efficacy and safety, we plan

to conduct a randomized, double-blind, placebo-controlled study with

more objective measurements to document clinical improvement. The

limiting factor in conducting that trial will be our ability to

recruit patients with this relatively rare disorder. "

Venlafaxine is approved for the treatment of depression, and has been

used as well for the management of obsessive-compulsive disorder and

anxiety. The 75 mg/day dose that has been effective in the patients

with erythromelalgia represents the recommended starting dose for

antidepressant treatment with venlafaxine. Its maximum recommended

dose is 375 mg/day.

Dr. Moiin noted he was prompted to try venlafaxine to manage

erythromelalgia based on a published report describing success in two

patients. Previously, he had prescribed serotoninergic

antidepressants, including paroxetine (Paxil) and fluoxetine

(Prozac), for some patients with erythromelalgia, but found those

agents were ineffective. Based on that experience, Dr. Moiin and Dr.

Yashar postulate the noradrenergic activity of venlafaxine is

important in its efficacy.

" The pathogenesis of primary erythromelalgia is not known for

certain, but histologic studies of affected skin show evidence of

decreased sympathetic innervation and deficient sympathetic

regulation. By inhibiting norepinephrine reuptake, venlafaxine may

address those defects, " said Dr. Yashar, dermatology resident at

Henry Ford Hospital, Detroit.

Via its serotoninergic effects, venlafaxine could alter platelet

function and reduce platelet plug formation that might contribute to

symptoms of erythromelalgia.

Anticoagulant effects pull trigger

" There is thought that erythromelalgia-associated pain might arise

from clumping and coagulation of platelets in the small vessels of

the extremities. In fact, it is believed that the benefit associated

with aspirin treatment is due at least in part to its anticoagulant

effects. Studies with venlafaxine and selective serotonin reuptake

inhibitors show they can affect platelets, and perhaps the activity

of venlafaxine is mediated at that level as well, " Dr. Yashar said.

Dr. Moiin proposed that the mechanism of venlafaxine's efficacy might

also be secondary to some effects at the level of the central nervous

system and not due wholly to peripheral activity.

" Recent studies report a role of venlafaxine in treating hot flashes

in postmenopausal women and in men receiving hormonal ablation

therapy for prostate cancer. Those findings would suggest venlafaxine

can affect the peripheral vasculature through a central mechanism, "

Dr. Moiin said.

Effexor is a product of Wyeth-Ayerst. Neither Dr. Moiin nor Dr.

Yashar has any financial interest in the product. DT