Types of pain
Depending on the cause of your facial pain, medication may significantly lower your pain. There are two main types of pain. Nociceptive is caused by tissue damage. Nociceptors are a type of receptor that detect potentially harmful stimuli. Examples of injuries that cause nociceptive pain are bone breaks, sprains, bruises, burns, and joint damage due to injury or arthritis.
In contrast, neuropathic pain is linked to the body’s nervous system. Examples of neuropathic pain include postherpetic neuralgia (a complication of shingles), entrapment neuropathies such as carpal tunnel syndrome, peripheral neuropathy, and facial pain due to neurological damage. This is an important concept, as certain medications work better for each type of pain.
Medication for neuropathic facial pain
Most drugs used for trigeminal neuropathic pain are used off-label. This means your doctor prescribed the drug for a different purpose than what the FDA approved. Oftentimes, people with neuropathic facial pain try combinations of drugs and change doses over time in attempts to find their medication “sweet spot”. The choice of a medication for facial pain is dependent upon multiple factors, some of which are individual to you.
Your pharmacist can make sure the medications you need are in stock for you, and can answer any questions you have about drug interactions and side effects. If your pharmacist knows you and your prescription needs, he or she will be less likely to question your medication before filling your prescriptions.
Trigeminal neuralgia and other forms of neuropathic facial pain are treated with classes of drugs referred to as antiepileptic medications (AEDs) or antidepressants (ADs). Drugs for nociceptive pain, such as acetaminophen or ibuprofen, are not effective for TN.
Medical treatment for facial pain
Ideally, the doctor and patient want the same thing: to control pain as soon as possible with a safe medication that works at a low dose and does not cause major side effects. It is often necessary to adjust the dose of the medication over time, trying to achieve a balance between pain control and safety.
For first line therapy, carbamazepine or one of its derivatives is often chosen. About 70 percent of patients experience significant pain relief, at least for the short term. There are a variety of other AEDs that have been tried to relieve TN pain, and many of them have been effective in certain patients. These include gabapentin, pregabalin, phenytoin, lamotrigine and topiramate. Some other non-AEDs that may be helpful include baclofen, nortriptyline and amitriptyline.
Medication side effects
What should you look out for from medical treatment of neuropathic facial pain? Adverse effects (AEs) may be divided into those that are dose-dependent, and idiosyncratic (dose independent). In general, dose dependent AEs are more common and can be mitigated with either a reduction in total daily dose, spreading the total daily dose into more frequent intervals, or if it exists, using a longer acting version of the same medication. Idiosyncratic AEs may occur at any dose, at any time, and require that the medication be discontinued.
The most common dose-dependent AEs from TN medications are those related to the nervous system and to the gastrointestinal system. Nervous system AEs may include dizziness, balance difficulties, double vision, memory problems or fatigue. Idiosyncratic AEs are rare. They are unpredictable, and while they are more common during the beginning of medication treatment, they may occur at any time. Some examples of these include severe skin rashes, low blood cell counts, and liver problems.
Drugs that are classified as anticonvulsants are known to be the most effective in treating trigeminal neuropathic pain. This is because they reduce the electrical conductivity of nerves throughout the body. By doing so they reduce the likelihood of shock-like pain occurring.
Stopping a medication
Stopping your medication can be as challenging as starting it. It is likely that, at some point in your facial pain journey, you will stop taking a drug. You may be switching from one drug to another. Your pain may have resolved through a surgical intervention. You may be in remission.
Unless your doctor tells you to stop abruptly because of a serious drug reaction or interaction, you must wean off the drug slowly, anywhere from a few days to a few weeks before making dose changes. There are uncomfortable, and sometimes dangerous consequences if you titrate off too quickly. Many people experience lightheadedness and nausea, or a rebound effect- a temporary return of the pain. Agitation, confusion, and disorientation can also occur. If you are taking more than one drug, stop one at a time.
What are the main drugs for facial pain?
If your doctor suspects that you have trigeminal neuralgia, you will likely be prescribed an anticonvulsant drug. If you have ‘classical’ trigeminal neuralgia, these medications will likely improve your pain, and you may not need further treatment. Over time, you may stop responding to this medication, or you may experience side effects. The role of anticonvulsant drugs in the treatment of neuropathic pain is evolving and has been clearly demonstrated with gabapentin and carbamazepine.
Why are anticonvulsants prescribed for facial pain?
Your doctor may refer to an anticonvulsant as an antiepileptic or an antiseizure agent, as these drugs are designed to treat epilepsy. Anticonvulsants, or anti-seizure medications, work as adjuvant analgesics. That means they can treat some types of chronic pain even though they are not designed for that purpose. In trigeminal neuralgia and several other forms of trigeminal neuropathic pain, the ‘lightning-like’ pain in brief attacks are not usually improved with analgesics such as aspirin, Tylenol, ibuprofen, and narcotics.
Carbamazepine (Tegretol) was traditionally the mainstay anti-seizure medication for neuropathic pain, especially for the treatment of trigeminal neuralgia (for which it is FDA approved). It’s also effective for diabetic neuropathy pain and postherpetic neuralgia.
Carbamazepine (Tegretol, Carbatrol, Epitol), the first anticonvulsant studied in clinical trials, alleviates pain by decreasing conductance (slowing the nerve’s conduction of pain signals) in sodium channels, which have a critical role in the development and maintenance of several pain syndromes, including inflammatory pain, neuropathic pain, and central pain associated with spinal cord injury. Beneficial results have also been reported in glossopharyngeal neuralgia.
Oxcarbazepine (Trileptal), lamotrigine (Lamictal) and phenytoin (Dilantin, Phenytek) are other anticonvulsants. They work by decreasing abnormal electrical activity in the brain. Other drugs, including clonazepam (Klonopin) and gabapentin (Neurontin, Gralise, others), also may be used.
Gabapentin is approved for the treatment of lasting postherpetic neuralgia. It is also effective for treating diabetic neuropathy. Gabapentin is used to relieve the pain of postherpetic neuralgia (PHN)- the burning, stabbing pain or aches after an attack of shingles). Gabapentin relieves the pain of PHN by changing the way the body senses pain. Gabapentin has the most clearly demonstrated analgesic effect for the treatment of neuropathic pain, specifically for treatment of painful diabetic neuropathy and postherpetic neuralgia.
Pregabalin is used to treat epilepsy and anxiety. It is also taken to treat nerve pain. Nerve pain can be caused by different illnesses including diabetes and shingles, or an injury. Pregabalin is indicated for pain associated with trigeminal neuralgia; beneficial results have also been reported in glossopharyngeal neuralgia; carbamazepine is not a simple analgesic and should not be used for the relief of trivial aches or pains. Pregabalin has also been found effective in the treatment of generalized anxiety disorder (GAD), which can aid people with chronic pain to relieve pain and improve sleep. Pregabalin can be a valuable addition to the limited options for the treatment of neuropathic pain. It may be more cost-effective than high-dose gabapentin and may be effective in patients who have previously failed to respond to gabapentin.
Side effects of anticonvulsants
Anti-seizure medications have relatively few side effects when compared to other long-term pain medication use, though a few are worth mentioning. The main side effects include:
Anti-seizure medications may also cause the following side effects:
- Confusion or trouble concentrating
- Loss of balance or trouble with coordination
- Double vision
- Slurred speech
- Loss of appetite
- Dry mouth