Medication Treatment Options for those with Pudendal Neuralgia

When starting a new medication, it is important to have close contact with your doctor. There are no comprehensive studies on utilizing these medications with pudendal neuralgia. Most neuropathic pain studies are conducted on those with diabetic neuropathies, trigeminal neuralgia and other neuropathies like post herpetic neuralgia. While some medications may work better with certain types of neuropathy, some facts are included here about how each of these medications have helped or not helped those suffering from various neuropathies.

Pain is one of the most common reasons that people seek medical care. An estimated 50 million people suffer from chronic nonmalignant pain, or pain of greater than 3 months’ duration that is not related to cancer. Pain results in a staggering 40 million physician office visits per year, accompanied by approximately 4 billion lost work days, $65 billion in lost work productivity and $3 billion in over-the-counter analgesics. Above all, it results in a dramatically decreased quality of life for the person who experiences it. In a Gallop Poll, 69% of cancer patients stated they would consider suicide if they felt their pain was inadequately controlled.

Optimizing pain relief is crucial to helping a person regain control of his or her life.

Pathology of Neuropathic Pain:

According to the “gate control” pain theory, injury to peripheral nerves or nerves descending from the spinal cord results in disinhibition of the nerve’s impulses at the spinal cord “gate,” which results in pain. Mechanosensitivity, spontaneous activity and increased responsiveness to both beta-adrenergic agonists and sympathetic chain stimulation also contribute to the pain.

Medications can also result in neuropathies, sometimes with associated pain. Isoniazid and hydralazine induce neuropathy by depleting pyridoxine. Ironically, megadoses of pyridoxine also cause neuropathy. Other medications have reversible dose-related effects. These include amiodarone, statins, dapsone, nucleoside analogs, paclitaxel and vincristine. A dose-dependent neuropathy is associated with cisplatin, but may not resolve and possibly worsen with drug discontinuation.

Signs and Symptoms

Several features of neuropathy distinguish it from other types of pain. Pain is delayed in onset after the injury occurs. People often describe their pain as “electrical” or “burning.” Other descriptors include feelings of extreme cold, “like frostbite,” despite an absence of temperature changes upon physical exam. Sometimes people can experience numbness, tingling, or “needles and pins” sensations. Pain descriptors vary between people. PN sufferers report that their pain is worse in the evening and better during the morning. Most can’t wear tight clothing and opt to wear loose fitting clothing.

Pudendal neuralgia involves signs of sensory dysfunction on physical examination. There may be motor dysfunction as well, such as urinary or fecal incontinence. Pudendal neuralgia sufferers can also often develop secondary myofascial pain.

Certain physical examination techniques help to identify abnormal sensory perceptions. People may have allodynia, a painful response to a typically nonpainful stimulus. Allodynia is elicited by brushing the affected area with a fingertip or cotton swab, or by thermal stimulation with a cold or warm object. Patients sometimes experience hyperpathia, an exaggerated pain response to a minor painful response, such as pinpricks. The pain tends to increase with repeated exposure, may spread outside of the contacted area (summation), and may include painful after-sensations.

Pudendal Neuralgia clearly can impact a person’s ability to carry out his or her activities through out the day. Increased pain during the night interferes with sleep. A person may find themselves guarding the areas that hurt the most, limit social activities, or develop depression. Pain relief is important to improve the person’s quality of life.

What to Expect

While the first goal of therapy is to relieve pain, goals should be realistic. People often hope for a “cure,” but this is not always possible.. A more realistic goal is to decrease pain to a tolerable level. Successful treatment should improve your ability to take care of yourself, to do daily chores around the house and to be able to socialize with friends and family.

Non Medication Management

Some non medication management techniques include lifestyle changes, physical therapy, occupational therapy, cold laser therapy, radio frequency ablation, different types of nerve blocks ie..pudendal nerve block, ganglion impar block, biofeedback, relaxation therapy, meditation, acupuncture and hypnosis. Some people with pudendal neuralgia have also started using herbal treatments, with some success. It’s very important that you speak with your doctor first, before starting a herbal program, to make sure that there are no interactions with your current medication.

Medication Management

Topical Agents: Topical agents offer the advantage of local relief without systemic toxicity. Capsaicin cream, which contains an extract of chili peppers, is sometimes used to treat neuropathic pain. It may act on unmyelinated primary afferent nerves by depleting substance P, a peptide thought to be involved in pain transmission. Depletion requires repeated and consistent use of capsaicin. The most common side effect is a burning sensation that decreases with consistent use.

Lidocaine may be used topically. It comes in two forms, one is an ointment form and the other is a patch form.  There are also compounded topical agents that can be prescribe with various medications such as gabapentin and ketamine.

Antidepressants: Both tricyclic antidepressants and serotonin reuptake inhibitors are used to treat pudendal neuralgia.  Numerous clinical trials demonstrate the safety and efficacy of TCAs. Amitriptyline was the first tricyclic used to treat neuropathy, and it is still widely prescribed. Amitriptyline also has a high incidence of anticholinergic side effects. This can lead to delirium in elderly persons and should be avoided in that population. Desipramine and nortriptyline, which have the least anticholinergic activity of the TCAs, are equally efficacious substitutes. The pain-relieving properties of TCAs occur independently of their effect on mood.

Some of the side effects of TCAs have proarrhythmic effects. Anyone taking this medication should have a baseline ECG, with a repeat after achieving a therapeutic dose. The greatest risk for developing arrhythmias occurs as the medication dose goes higher. For desipramine, for doses over 70mg, an ECG should be ordered. Other risk factors include congestive heart failure, active ischemic heart disease, and bundle branch block. TCAs should also be avoided in people with closed-angle glaucoma, benign prostatic hypertrophy, uncontrolled seizure disorder, and bipolar disorder.

Serotonin specific reuptake inhibitors (SSRIs) have less consistent effects on people with pudendal neuralgia, although some have had great success with it. Again, there can be trial and error in finding the right medication. Some of the typical SSRI’s are Paxil, Zoloft, Lexapro, Celexa and Prozac.

The last type of antidepressant is called an SSNRI. This would include medications like Cymbalta and Effexor, with Cymbalta being widely used to treat pudendal neuralgia symptoms. They both combine the norepinephrine-reuptake inhibiting effects of TCAs with the serotonin-reuptake inhibiting effects of the SSRIs, without the anticholinergic side effects. It appears that serotonin reuptake inhibitors combined with norepinephrine reuptake inhibitors have a better effect on those suffering with pudendal neuralgia. Cymbalta is a newer form of antidepressant, which is now FDA approved to treat neuropathic pain. The side effects can include increased blood pressure and/or hypertension, irritability, insomnia, nausea, vomiting and constipation.

Anticonvulsants: Anticonvulsants are considered second-line therapy for most neuropathies. Carbamazepine (Tegretol), phenytoin (Dilantin), gabapentin (Neurontin), lamotrigine (Lamictal) and pregbalin (Lyrica) are all used to treat neuropathic pain. The ones most widely utilized for pudendal neuralgia are Lyrica and Neurontin.

Lyrica – Lyrica is now being used to treat Pudendal Neuralgia. It is FDA approved to treat neuropathic pain. There are some studies showing that the combination of Lyrica and Cymbalta may give pudendal neuralgia sufferers greater relief than utilizing one of them alone.

Carbamazepine: Carbamazepine is considered first-line therapy for trigeminal neuralgia. Clinical trials suggest its efficacy for treating diabetic neuropathy, but results are mixed for postherpetic neuralgia.

The most common side effects of carbamazepine are dizziness, giddiness and dyspepsia. These symptoms are dose-related, and can be minimized by starting with low doses. Carbamazepine carries a black box warning for blood dyscrasias, including agranulocytosis and aplastic anemia. Both of these side effects are idiosyncratic.

Gabapentin: Until recently, evidence for treating neuropathies with gabapentin was based on anecdotal information or case studies. However, objective evidence from randomized, double-blind trials is available. Gabapentin is more effective than placebo at reducing diabetic neuropathy and postherpetic neuralgia-associated pain. The most common side effects associated with gabapentin are asthenia, headache, dizziness and somnolence. Ironically, gabapentin has been reported to induce polyneuropathy.

Lamotrigine: Lamotrigine shows promise for decreasing pain associated with trigeminal neuralgia. However, it was no better than placebo when used to treat other types of neuropathic pain. The side effect of most concern is skin rash, including Steven-Johnson’s syndrome. To avoid this, therapy should be initiated with low doses and titrated slowly to a therapeutic dose.

Analgesics: Opioid treatment of neuropathic pain has been controversial over the past 10-15 years. Opioids were thought to be ineffective for treating neuropathic pain, but evidence is mounting for the use of opioids in patients who have failed other modalities. In addition, novel analgesics such as tramadol may offer new options in treating neuropathies.

Benzodiazepines:  Patients with tight pelvic floor muscles due to pudendal neuralgia may benefit from drugs such as diazepam (valium), lorazepam (ativan), or clonazepam (klonopin), drugs which act as muscle relaxers.  Exactly how benzodiazepines work is not known but they act on the neurotransmitter gamma aminobutyric acid (GABA), a substance that decreases nerve activity. Clonazepam has also been used as an anti-seizure drug.

Ambien is a non-benzodiazepine hypnotic that shares some of the same pharmacological characteristics as benzodiazepines.  Many pudendal neuralgia patients who have difficulty sleeping find ambien helpful in allowing them to sleep.

Flerxeril and soma are two other muscle relaxers that may be helpful in reducing the pelvic floor muscle tension associated with pudendal neuralgia.

Vagina or Rectal Suppositories: There are several types of suppositories that some patients with pudendal neuralgia have found helpful in relieving symptoms without as many systemic side effects as some of the oral medications.  These include belladonna and opioid suppositories and valium suppositories that help relax pelvic floor muscles.

NSAIDs: Neuropathic pain relief from NSAIDs has varied widely with the type of neuropathy and agent used. In particular, with pudendal neuralgia, if there is an inflammation of the nerve, utilizing medications like ibuprofen may be of help.

Tramadol: Interest in tramadol for treating neuropathic pain stems from its inhibition of norepinephrine reuptake and release of serotonin, similar to the tricyclic antidepressants. Its active metabolite, (+) M1, also binds to the mu-opioid receptor. Only a few small clinical studies have examined tramadol’s efficacy on neuropathic pain. In one study of 34 patients with polyneuropathy of varying etiologies, tramadol was superior to placebo at reducing both ongoing and touch-evoked pain The most common side effects of tramadol are somnolence, constipation, and headache. Tramadol should be avoided in patients with a history of seizures or substance abuse. In addition, there is a risk for serotonin syndrome if given with other serotonergic agents, such as SSRIs, MAO inhibitors, and triptans.

Opioids: A small body of evidence suggests that opioids may relieve neuropathic pain in a select population of patients. Opioid analgesia appears to be dose-dependent and related to serum levels when used to treat neuropathic pain. Intravenous fentanyl is more effective than placebo at reducing neuropathic pain, regardless of etiology. Controlled-release oxycodone may decrease pain and allodynia associated with postherpetic neuralgia when given at doses of 20-60 mg/day. Morphine has also been used to treat nerve injuries. In general, neuropathic pain relief with opioids remains controversial. Neuropathic pain may be less responsive to opioids than other types of pain, and often requires the addition of one of the previously discussed agents to provide relief. Many pudendal pain sufferers report that opioids help to keep the “edge off” of the pain, but do not totally take away the pain. If you feel that your pain is not being managed well with non opiod medications, then speaking to your doctor about medication management with opiods would be the next step in managing the pain.

Other Agents: Baclofen is used as a first-line agent to treat trigeminal neuralgia, with or without anticonvulsants. Baclofen blocks both presynaptic and postsynaptic GABA B receptors, which are concentrated in the spinal cord on the primary afferent neurons. This decreases the response of nerves to electrical stimulation and other pain stimuli. It may also inhibit the release of substance P. The most common side effect is drowsiness, which is partially avoidable by starting with a low dose and titrating slowly.

Ketamine, an N-methyl-D-aspartic acid (NMDA) receptor antagonist, has garnered increased interest for treating neuropathic pain in the past decade. New evidence suggests that NMDA receptors play a role in mediating neuropathic pain. In a comparative trial, ketamine, but not morphine, relieved continuous and lancinating pain, and allodynia in postherpetic neuralgia. Most studies done to date used short-term infusions of ketamine. Long-term parenteral use of ketamine can lead to painful indurations at the site of injection and psychomimetic effects. Ketamine is chemically related to phencyclidine (PCP), and causes sedation, slowed reaction times and hallucinations with long-term use.

Neuropathic pain remains a clinical challenge for treatment. Any medication used to treat neuropathy must be weighed for benefits and risks before using. It may take several trials to find an effective medication or combination of medications. People may need support throughout the process. Neuropathic pain often requires a combination of medication and nonpharmacologic modalities in order to achieve adequate pain relief.