Here some snippets I extracted from the literature:
Carbamazepine
Diagnostic challenges of nonodontogenic toothache
Case
Tooth #45 responded within normal limits when tested with cold and electronic pulp tester.
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The presenting complaint was diagnosed as trigeminal neuralgia, and carbamazepine was recommended as the treatment of choice. 200 mg of carbamazepine, taken twice daily, was prescribed. The patient's symptoms resolved within 2 weeks.
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Clinical features of atypical odontalgia; three cases and literature reviews
Although carbamazepine had been prescribed at the otorhinolaryngology clinic, it was not effective. Gabapentin and pregabalin had been pre- scribed by the psychiatric department of the university hospital but they were also not effective.
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Treatment of chronic pain in dentistry using anticonvulsants
The carbamazepine is used since the 60s, but their prolonged use can alter liver function.
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The most common drugs used to treat this kind of chronic pain are anticonvulsants such as phenytoin, carbamazepine, gabapentin, topiramate and benzodiazepines like diazepam and clonazepam, which in addition to anxiolysis' activity, can also exercise anticonvulsant fuction3-4.
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Phenytoin and carbamazepine inhibit the function of sodium channels, whereas gabapentin inhibits the function of calcium channels4.
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In most cases the drug of first choice is Carbamazepine, being effective when prescribed in the dose of 300 milligrams, 3-4 times a day. Medications for the treatment of trigeminal neuralgia are effective in approximately 80% of cases.
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According to Mendes et al.7, carbamazepine has been used since the 1960s and demonstrated efficacy in approximately 60% to 80% of cases. However, its prolonged use triggers complications, including tremors, drowsiness, dizziness, diarrhea, epigastralgia and changes of liver function. It is indicated during the course of the drug therapy, periodic laboratory tests and serum levels of carbamazepine, due to the possibility of development of agranulocytosis and changes in liver function.
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Diagnostic Challenges of Neuropathic Tooth Pain
The oral surgeon prescribed carbamazepine, 200 mg 3 times daily. The patient’s symptoms resolved within 2 weeks. Against the surgeon’s advice, the patient discontinued the medication after 5 weeks believing that the problem was solved. Fortunately, the pain did not recur.
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Trigeminal Neuralgia or Toothache
Carbamazepine, commonly used in trigeminal neuralgia, may help for toothache as well, which adds even more confusion. Practicing neurology for years, I have seen removed teeth in trigeminal neuralgia, as well toothache treated as trigeminal neuralgia.
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https://paindata.org/documents/drugs-carbamazepine.pdf
Although carbamazepine is not licensed for the treatment of general chronic pain, it has been shown to be helpful in the management of certain types of pain, such as facial pain caused by Trigeminal Neuralgia. You are on this medicine to treat your pain.
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Carbamazepine works by changing the way that nerves send messages to your brain. If the messages are reduced, then the pain will be reduced.
How long will it take to work?
It may take 2 - 4 weeks before you feel any pain relief. It may take longer (up to 2 months) to get to the right dose for you and to allow the medicine to build up in your body. Carbamazepine does not work for everyone. If you do not feel any improvement in your pain after 6 – 8 weeks, do not suddenly stop taking the tablets but speak to your doctor, community pharmacist or nurse.
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In trials, most medicines for long-term pain provide on average a 30% reduction in pain. Some pains do not seem to respond to any painkilling medicines. Medicines work best if you combine them with other ways of managing symptoms such as regular activity and exercise and doing things that are satisfying or enjoyable, such as work, study and social activities. Setting goals to help improve your life is an important way to see if these medicines are helping.
When should I take it?
You should take carbamazepine two or three times a day, morning, afternoon and night. It is important to take your carbamazepine
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regularly, as prescribed for it to work properly. It is not a medication that you should use on an ‘as required’ basis. You usually start carbamazepine at a low dose and increase it slowly to find the best dose for you. You and your doctor, nurse or community pharmacist will decide between you how quickly you increase your medicine. Normally you need a minimum dose of 100mg twice a day to get any benefit and the dose may need to be increased to 200mg three times a day.
Most common side effects
Dizziness
Tiredness
Drowsiness
Unsteady on feet
Difficulty controlling movements
Nausea and vomiting
Skin reaction (Hives)
Changes in liver function
Not so common side effects
Fluid retention
Weight gain
Blurred vision
Dry mouth
Headache
Easy bruising
Low sodium levels
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Generally side effects are worse after starting carbamazepine or increasing the dose. It is important to persist in taking carbamazepine as these side effects are usually mild and will wear off after several days.
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Drowsiness is usually temporary. If you feel drowsy, you should not drive or operate machinery.
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Drowsiness may occur as you increase your dose. If you feel especially drowsy in the morning it may help to take the night time dose earlier in the evening.
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The risk of drowsiness may be increased if you are taking other medicines for pain such as other anticonvulsant medications, antidepressants or morphine like medicines.
Can I drink alcohol?
Alcohol and carbamazepine together cause sleepiness and poor concentration. You should avoid alcohol completely when you first start taking carbamazepine or when you increase your dose. You should also avoid alcohol if you are going to drive or operate machinery.
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Once you are on a stable dose, you should be able to drink modest amounts of alcohol, but only if the drowsiness has stopped.
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You must take care with alcohol if you are also prescribed other medications that can cause sleepiness and poor concentration.
