This article is one in a series on Medications for Pain…  what are your choices?  how do various medications work?  what are the pros and cons?  how about side effects?  (Discuss these ideas with your doctor.  Don’t make any changes to your treatment by yourself.)

The class of medication we’ll look at today is Anesthetics, which are medications used to prevent sensations, particularly pain.  Within this class, there are many different medications, and many ways to use these medications, including:

• Topical (through the skin), for example, the Lidoderm patch.  This delivers anesthetic to nerves near the skin which are irritated, and can stay on for 12 hours or more, so you get a much longer effect than a cream.

• By mouth in pill form.
• Injection – either at a local site (“local anesthesia”) or covering a broader area (“regional anesthesia”).  For injections, the anesthetic is often combined with a steroid medication.
• Intravenous (IV), for which an inpatient or outpatient hospital stay is needed.

Effect of Anesthetics:  Anesthetics work by stabilizing nerve membranes, so it’s more difficult to transmit nerve signals, including pain signals.

Uses of Anesthetics:  Although anesthetics are commonly used, there are few FDA-approved indications for anesthetics in specific pain disorders.  The Lidoderm patch is FDA-approved for the pain of shingles (“PHN” – Post Herpetic Neuralgia).  It’s also used for many other conditions, e.g. CRPS (Complex Regional Pain Disorder or RSD), the pain of diabetes (“DPN” – Diabetic Peripheral Neuropathy), low back pain, etc.  Local or regional injections are used for low back pain, other spinal pain, CRPS, etc.

Side Effects:

Anesthetics used on the skin can cause skin irritation, either because of the anesthetic itself or the adhesive in the patch.

Injections often cause temporary site irritation, either from the medication which is injected, or simply from injecting liquid inside your body.  By their very nature, injections are also imprecise, even when your doctor uses a type of picture (for example, a fluoroscope) to guide the needle.  Too far away from the right spot and the injection may not be effective.  Too close, especially to a major nerve, and more significant nerve irritation and pain can result.

IV anesthetics can cause a drop in blood pressure or heart beat irregularities, so these must be monitored during the infusion.

Cost and Insurance Coverage
The Lidoderm patch is an expensive product, but can help a great deal with irritation in the nerves near the skin.  For many disorders, it’s worth trying.

Insurance coverage for IV anesthetic treatment, for example, a Lidocaine or Ketamine infusion, can be very expensive.  The cost is primarily for the hospital charges rather than the medication itself.  There are some physicians who now use outpatient Ketamine infusions, which are much less expensive than an inpatient hospital stay.  However, Lidocaine is usually thought to be a more conservative treatment.  I’ve seen quite a number of patients whose insurance will pay for outpatient Ketamine, because it’s less expensive, rather than for inpatient Lidocaine, even if clinically that’s more appropriate.  I feel it’s a really unfortunate case of money winning over good medical care.

Next Monday, we’ll look at a particular anesthetic, Ketamine.  Other articles in this series:

• Medication 101:  What Are My Options For Pain Treatment
• NSAIDS:  Aspirin, Motrin, Celebrex
• Anticonvulsants
• Antidepressants
• Ketamine
• Muscle Relaxants
• Blood Pressure Medication
• Anti-Psychotics
• Narcotics (Opiates)
• Medication Advances Coming Soon
• Research Advances