What is neuropathic pain?
Neuropathic pain occurs when nerve cells do not work properly due to damage or irritation and spontaneously generate signals that we perceive as pain or discomfort. Such pain is often described as burning or electrifying, shooting, stabbing, unpredictable. Alongside back pain and headaches, neuropathic pain is one of the most common chronic pain problems.
Neuropathic pain often feels different to the pain we are familiar with from a strain or sprain. It can be caused by accidents, operations, amputations, long-term diabetes mellitus, shingles or diseases of the nervous system (e.g. multiple sclerosis). A common cause can also be nerve entrapment, e.g. due to a slipped disc.
There are various therapeutic options for treating neuropathic pain, with medication playing a major role. Conventional pain medication (paracetamol, anti-inflammatory drugs) is often of limited help. As the cause of the pain does not lie in a muscle, bone or joint, but directly in the damaged/irritated nerve, other active substances are used. These usually belong to the group of antidepressants or anti-epileptics, as these substances target the nervous system more specifically than classic painkillers do.
At the beginning of a treatment
Targeted drug treatment of neuropathic pain is only considered if it can be assumed that neuropathic pain is present. At the beginning, the expected benefits of the therapy and the possible side effects are discussed.
The existing pain problem and the patient's other medical situation play an important role in the selection of a particular medication.
“Off-label” treatments
The term “off-label treatment” is used when a medication is used to treat a condition for which it has no official approval. For neuropathic pain in particular, many drugs that were originally approved for a different purpose have proven to be effective. In particular, these are drugs for depression or epilepsy. Only experience gained after approval has shown that these substances can also be effective against neuropathic pain. Even if their efficacy has now been clinically confirmed, approval for the treatment of neuropathic pain is not mandatory. This is why some of these drugs are now being used “off label” for the treatment of pain.
The following medications are frequently used in pain medicine to treat neuropathic pain (list is not exhaustive):
- Tricyclic antidepressants (amitriptyline, trimipramine)
- Selective serotonin-norepinephrine reuptake inhibitors (mirtazapine, duloxetine, venlafaxine)
- Antiepileptic drugs (pregabalin, gabapentin, topiramate, carbamazepine, oxcarbazepine)
Determining the correct dose
Medication for neuropathic pain is usually started with a low dose, which is gradually increased over time. The aim is to determine the optimum dose with the maximum possible effect on pain with minimal side effects.
Sometimes the planned dose increase is not possible if the side effects of the medication are too severe. In this case, the treatment strategy must be reconsidered and, if necessary, a switch to another medication is discussed.
When can I expect a reduction in pain?
Drug treatment of neuropathic pain usually takes some time before the desired effect occurs. Sometimes it takes several weeks for the pain-reducing effect to be established.
In this context, it is also important to bear in mind that every person is different. The reactions to a particular drug treatment are therefore different. For some patients, anti-neuropathic medication helps from the very first day, while others require more patience.
The i.v. local anesthetic test as a guide
If there is uncertainty as to whether anti-neuropathic drug therapy should be attempted or continued, an outpatient intravenous local anesthetic test can be helpful. The recorded intravenous administration of the local anesthetic lidocaine can be used to determine whether or not a pain condition can be effectively treated with certain anti-neuropathic drugs.
What if the medication does not help?
If neuropathic pain persists despite drug therapy or if side effects make therapy impossible, the treatment strategy must be reconsidered. If necessary, a change to a different medication, possibly including interventional procedures, should be discussed.
Driving and operating machinery
During the first 1 - 3 weeks of therapy, during the adjustment phase, when increasing the dose or when switching to another anti-neuropathic medication, driving or operating machinery should be avoided. During this time, side effects are common which restrict the ability to react.
Alcohol should only be consumed with caution during treatment with anti-neuropathic medication. Alcohol further impairs the ability to react, so driving should be avoided after drinking alcohol.
