A retrospective review of 38 women who used 2% amitriptyline and 2% baclofen in a Lipoderm cream for localized vestibular pain found that 53% experienced an improvement in symptoms of at least 60%, but there was no change in the frequency of sexual intercourse.1
Do tricyclic antidepressants ease chronic pain?
Dr. Lonky: Let’s talk, for a moment, about the use of oral tricyclic antidepressants in the treatment of vulvar pain syndromes. What do we know?
Dr. Haefner: Tricyclic antidepressants are a common treatment for vulvar pain. This group of drugs (including amitriptyline [Elavil], nortriptyline [Pamelor], and desipramine [Norpramin]) has been used to treat many idiopathic chronic pain conditions. Published and presented reports indicate that these drugs elicit about a 60% response rate for various pain conditions. A trial by the National Institutes of Health (NIH) is under way, analyzing the use of antidepressants in women who have vulvar pain.
Although treatment with tricyclic antidepressants has generally been reserved for women who have generalized vulvodynia, recent reports have found these medications to be helpful in the treatment of vestibular pain as well. The mechanism of action is thought to be related to inhibition of the reuptake of transmitters—specifically, norepinephrine and serotonin. However, the mechanism of action may be more closely related to anticholinergic effects. Tricyclics affect sodium channels and the N-methyl-d-aspartate (NMDA) receptor.
If you choose to prescribe one of these medications, consider emphasizing to the patient its effect on the sensation of pain rather than its effect on depression.
Dr. Lonky: Are there any types of patients who should not take a tricyclic?
Dr. Haefner: Yes. A patient should not take a tricyclic if she is pregnant, breastfeeding, or planning to conceive. These medicines also add to the effects of alcohol and other central nervous system depressants.
Dr. Lonky: What dosage is recommended?
Dr. Haefner: The dosage for pain control varies, depending on the age of the patient and the particular agent used. Amitriptyline is often used as a first-line medication. I start the patient on 10 to 25 mg nightly and increase that amount by 10 to 25 mg weekly, not to exceed 150 mg daily. A sample regimen might be 10 mg at bedtime for 1 week. If symptoms persist, increase the dose to 20 mg at bedtime for another week, and so on. Once a dose is established that provides relief, the patient should continue to take that amount nightly. Advise the patient not to discontinue the drug abruptly. Rather, it should be weaned.
In patients who are 60 years or older, I give a starting dose of 5 to 10 mg and increase it by 10 mg weekly.
In all age groups, it is important to advise patients to avoid consuming more than one alcoholic beverage daily while taking this medication. And in reproductive-age women, contraception is critical.
Dr. Edwards: I call these drugs tricyclic medications rather than antidepressants. They are extremely useful in managing the neuropathic component of vulvar pain. Despite a recent, apparently well-conducted study showing a lack of benefit, my 25 years of personal clinical experience with tricyclics convince me that I should wait for follow-up studies before abandoning this therapy.3
The pain literature reports that higher doses than previously reported of tricyclic medications are needed for optimal management of neuropathic pain. Doses from 100 to 150 mg are often required for substantial improvement, and a major design flaw in many studies of the effect of tricyclic medications on vulvodynia is the use of an insufficient dose.
Because of their low cost and their effectiveness, tricyclic medications are my first-line therapy for women who do not suffer severe constipation or dry eyes. The effect on depression is a useful side effect, I find.
Dr. Gunter: Although adjuvant medications, such as antidepressants and anticonvulsants, are considered by more than 80% of practitioners to be effective for vulvodynia, it is important to understand that only one randomized, double-blind, placebo-controlled prospective study has evaluated this approach, and that study found a placebo response rate of 33%.3,7
Randomized studies indicate that low-dose amitriptyline (10–20 mg) and desipramine (150 mg) are ineffective for provoked vestibulodynia.3,8 Cohort and retrospective studies with higher doses of amitriptyline (40 to 60 mg/day) indicate that improvement in pain scores of 50% or more can be achieved for 47% to 59% of women who have localized provoked vestibulodynia and generalized unprovoked vulvodynia.9-11
Tricyclic antidepressants and anticonvulsants should be prescribed with caution for patients 65 years and older because they increase the risk of falls.