Medication Related Neuropathy

Today's post from nytimes.com (see link below) is a general look at how neuropathy can be caused by certain drugs you are taking. We all underestimate the toxicity of drugs over the long term but some of the ones listed here may surprise you. That said, by no means all people who take these drugs as prescribed, get neuropathy - it's mostly the exception rather than the rule but if you and your doctor are searching for reasons why you have neuropathic problems, it may be worth while looking at your medications to see if there's a possible link there.

Neuropathy Secondary to Drugs Reference from A.D.A.M. New York Times Health

Neuropathy secondary to drugs is a loss of sensation or movement in a part of the body due to nerve damage from a certain medicine.

Causes

The damage is caused by the toxic effects of certain medications on the peripheral nerves (nerves that are not in the brain or spinal cord). There may be damage to the axon part of the nerve cell, which interferes with nerve signals.

Most commonly, many nerves are involved (polyneuropathy). This usually causes sensation changes that begin in the outside parts of the body (distal) and move toward the center of the body (proximal). There may also be changes in movement, such as weakness.

Many medications may affect the development of neuropathy, including:
 
Heart or blood pressure medications
Amiodarone
Hydralazine
Perhexiline
Drugs used to fight cancer
Cisplatin
Docetaxel
Paclitaxel
Suramin
Vincristine
Drugs used to fight infections
Chloroquine
Isoniazid (INH) -- used against tuberculosis
Metronidazole (Flagyl)
Nitrofurantoin
Thalidomide (used to fight leprosy)
Drugs used to treat autoimmune disease
Etanercept
Infliximab
Leflunomide
Drugs used to treat skin conditions (Dapsone)
Anticonvulsants (phenytoin)
Anti-alcohol drugs (disulfiram)
Drugs to fight HIV
Didanosine (Videx)
Stavudine (Zerit)
Zalcitabine (Hivid)
Arsenic
Colchicine
Gold

Symptoms
Numbness, loss of sensation
Tingling, abnormal sensations
Weakness

Sensation changes usually begin in the feet or hands and move inward.

Exams and Tests

A brain and nervous system examination will be done.

Other tests include:
Blood tests to check levels of the medication (even normal blood levels of certain drugs may be toxic in elderly or certain other persons)
EMG and nerve conduction test of the electrical activity of nerves and muscles

Treatment

Treatment is based on the symptoms and how severe they are. The medication causing the neuropathy may be stopped, reduced in dose, or changed to another medication. (Never change any medication without first talking to your health care provider).

The following medications may be used to control pain:
Over-the-counter pain relievers may be helpful for mild pain (neuralgia).
Phenytoin, carbamazepine, gabapentin, pregabalin, duloxetine, or tricyclic antidepressants such as nortriptyline may reduce the stabbing pains some people experience.
Opiate pain relievers, such as morphine or fentanyl, may be needed to control severe pain.

Whenever possible, avoid or reduce medication use to lessen the risk of side effects.

If you have lost sensation, you may need to take safety measures to avoid injury.

Outlook (Prognosis)

Many people can partially or fully return to their normal function. The disorder does not usually cause life-threatening complications, but it can be uncomfortable or disabling.

Possible Complications
Inability to function at work or home because of permanent loss of sensation
Pain with tingling in the area of the nerve injury
Permanent loss of sensation (or rarely, movement) in an area
When to Contact a Medical Professional

Call your health care provider if you have a loss of sensation or movement of any area of the body while taking any medication.
Prevention

Your health care provider will closely monitor your treatment with any medication that may cause neuropathy. The goal is to keep the proper blood level of medication needed to control the disease and its symptoms while preventing the medication from reaching toxic levels.

References
Katirji B, Koontz D. Disorders of peripheral nerves. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC. Bradley’s Neurology in Clinical Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 76.

Weimer LH, Sachdev N. Update on medication-induced peripheral neuropathy. Curr Neurol Neurosci Rep. 2009;9(1):69-75.

http://www.nytimes.com/health/guides/disease/neuropathy-secondary-to-drugs/overview.html

TALK THERAPY NOT MEDICATION BEST FOR SOCIAL ANXIETY DISORDER

While antidepressants are the most commonly used treatment for social anxiety disorder, new research suggests that cognitive behavioral therapy (CBT) is more effective and, unlike medication, can have lasting effects long after treatment has stopped.

Social anxiety disorder is a psychiatric condition characterized by intense fear and avoidance of social situations and affects up to 13 percent of Americans and Europeans. Most people never receive treatment for the disorder. For those who do, medication is the more accessible treatment because there is a shortage of trained psychotherapists.

The findings of the study, a network meta-analysis that collected and analyzed data from 101 clinical trials comparing multiple types of medication and talk therapy, are published online Sept. 26 in The Lancet Psychiatry.

"Social anxiety is more than just shyness," says study leader Evan Mayo-Wilson, DPhil, a research scientist in the Department of Epidemiology at the Johns Hopkins Bloomberg School of Public Health. "People with this disorder can experience severe impairment, from shunning friendships to turning down promotions at work that would require increased social interaction. The good news from our study is that social anxiety is treatable. Now that we know what works best, we need to improve access to psychotherapy for those who are suffering."

The research was a collaboration between the Johns Hopkins Bloomberg School of Public Health, Oxford University and University College in London, where Mayo-Wilson formerly worked.

For the study, Mayo-Wilson and his colleagues analyzed data from 13,164 participants in 101 clinical trials. The participants all had severe and longstanding social anxiety. Approximately 9,000 received medication or a placebo pill, and more than 4,000 received a psychological intervention. Few of the trials looked at combining medication with talk therapy, and there was no evidence that combined therapy was better than talk therapy alone.

The data compared several different types of talk therapy and found individual CBT was the most effective. CBT is a form of treatment that focuses on relationships between thoughts, feelings and behaviors. It helps people challenge irrational fears and overcome their avoidance of social situations, Mayo-Wilson says.

For people who don't want talk therapy, or who lack access to CBT, the most commonly used antidepressants -- selective serotonin reuptake inhibitors (SSRIs) -- are effective, the researchers found. But they caution that medication can be associated with serious adverse events, that it doesn't work at all for many people, and that improvements in symptoms do not last after people stop taking the pills.

The researchers acknowledge that medication remains important but say it should be used as a second-line therapy for people who do not respond to or do not want psychological therapy. The group's analysis has already led to new treatment guidelines guidance in the U.K. and, Mayo-Wilson says, it could have a significant impact on policymaking and the organization of care in the U.S.

Social anxiety disorder typically begins in adolescence or early adulthood, and it can severely impair a person's daily functioning by impeding the formation of relationships, by negatively affecting performance at work or school, and by reducing overall quality of life. Because it strikes people at critical times in their social and educational development, social anxiety disorder can have important and lasting consequences.

"Greater investment in psychological therapies would improve quality of life, increase workplace productivity, and reduce healthcare costs," Mayo-Wilson says. "The healthcare system does not treat mental health equitably, but meeting demand isn't simply a matter of getting insurers to pay for psychological services. We need to improve infrastructure to treat mental health problems as the evidence shows they should be treated. We need more programs to train clinicians, more experienced supervisors who can work with new practitioners, more offices, and more support staff."