Abstract
The use of cannabidiol (CBD) as an adjuvant in the treatment of trigeminal neuralgia (TN) and postherpetic neuropathy has shown beneficial effects in patients refractory to conventional treatments. This case study describes a 57-year-old patient diagnosed with TN in 2019, initially treated with low-power laser therapy and oxcarbazepine. In 2021, she developed vesicular-bullous lesions on the right side of the supraorbital region, accompanied by severe pain confirmed by positive serology for shingles. Following the diagnosis of postherpetic neuropathy, the drug dose was adjusted and combined with laser therapy. However, the pain remained significant and reduced quality of life. In 2023, treatment was started with CannaMeds CBD Full Spectrum – 3000 mg/30 ml + CannaMeds CBG Isolate 1500 mg/30 ml. After 15 days, the patient appeared pain-free, allowing the laser to be discontinued and the drug dose to be reduced. CBD is a treatment option for patients who do not respond to conventional treatments.
Keywords: Cannabidiol (cannabidiol), neuralgia and cannabidiol (trigeminal neuralgia and cannabidiol), postherpetic neuralgia (postherpetic neuralgia), trigeminal neuralgia (trigeminal neuralgia)
Introduction
Trigeminal neuralgia (TN) causes brief, painful episodes of electric shock in the trigeminal nerve, while postherpetic neuralgia (PHN) is chronic pain following shingles.[1,2] Carbamazepine and oxcarbazepine are effective for PNS but have side effects.[3] Treatment for PHN includes tricyclic antidepressants, serotonin and norepinephrine reuptake inhibitors, pregabalin, gabapentin, tramadol, and capsaicin and lidocaine patches.[4] Neuropathic pain is difficult to treat due to the variability in drug response and adverse effects.[5]
Faced with these challenges, cannabinoid therapy is considered an adjunct, effective when conventional treatments fail.[6] Less invasive modalities, such as photobiomodulation, are also proposed.[6,7]
Objective
The objective of this study was to report a case of a patient with TN and postherpetic neuropathy in the face being treated with cannabidiol (CBD) and cannabigerol as an adjuvant.
Case Report
In 2019, a 57-year-old female patient presented at Christus University Center School of Dentistry with a neurologist’s diagnosis of TN. On physical examination, she exhibited allodynia and hyperalgesia in the V1 branch (ophthalmic) on the left side, severe pain rated grade 8 on the Visual Analog Scale (VAS), and difficulty performing daily activities. Treatment included oxcarbazepine 300 mg twice daily and low-intensity photobiomodulation therapy (4–6 joules) using infrared light with the DMC Therapy PLUS Laser at 11 points: 3 in the frontal region, 4 in the supraorbital region, and 3 near the scalp on both sides.
Over the next 20 months, the patient showed satisfactory pain control with a VAS pain score reduced to 0. In 2021, she returned with vesicular-bullous lesions in the left supraorbital region [Figure 1] accompanied by intense pain rated grade 9 on the VAS. Positive herpes zoster serology (IgG and IgM anti-varicella-zoster virus) led to a prescription of oral acyclovir 400 mg five times daily. It was noted that the patient had never received the herpes zoster vaccine. The initial diagnosis of TN was revised to postherpetic neuropathy due to persistent pain.
Figure 1.
Clinical photograph showing lesions of herpes zoster in the supraocular region (a). Clinical photograph showing lesions of herpes zoster recurrence in the supraocular region. Clinical photograph showing application points for low-power laser (b)
Treatment was adjusted to oxcarbazepine 300 mg three times daily along with low-intensity laser therapy (4J) after lesion resolution. However, inadequate pain control prompted referral to an infectious disease specialist. Treatment was revised to include acyclovir 400 mg for 90 days, cashew root extract, and laser therapy (6J) on the ophthalmic nerve. After 3 months, pain reduced to zero on the VAS with relief of pruritus from vesicular-bullous lesions.
Capsaicin 0.25 mg + lidocaine 2% was prescribed locally, and oxcarbazepine was reduced to twice daily while maintaining 4J laser therapy. Despite combination therapies, the patient reported insufficient pain control (VAS grade 7), leading to the addition of pregabalin 75 mg and reinstatement of oxcarbazepine three times daily.
In March 2023, the patient reported intense spontaneous and provoked pain, indicating a need for promising adjuvant therapy. Herbal therapy with CannaMeds CBD Full Spectrum (3000 mg/30 ml) and CannaMeds CBG Isolate (1500 mg/30 ml) was initiated, administered sublingually as prescribed.
The patient was encouraged to engage in water aerobics classes. After 15 days, she returned with no pain complaints, allowing discontinuation of photobiomodulation, pregabalin, and capsaicin. Oxcarbazepine dosage was reduced to twice daily. She reported effective pain control, improved quality of life, sleep, reduced nervousness, and anxiety attacks. The patient experienced no adverse effects from cannabis use.
On December 9, 2024, the patient received the first dose of the herpes zoster vaccine and reported zero pain on the VAS [Table 1].
Table 1.
Dates and events
| Date | Event |
|---|---|
| 2019 | Diagnosed with TN Symptoms: Severe pain (8/10 on the VAS) with allodynia and hyperalgesia in the left ophthalmic branch of the trigeminal nerve Treatment: Oxcarbazepine (300 mg twice daily) and received low-intensity photobiomodulation therapy with infrared light at 11 targeted points on the face and scalp |
| 2021 | Outcome: Initially experienced satisfactory pain control, with a pain score reduced to zero on the VAS New episode: Returned with vesicular-bullous lesions in the left supraorbital region, reporting intense pain rated as 9 out of 10 on the VAS Diagnosis: Was revised to PHN, confirmed by positive herpes zoster serology Treatment: Prescribed oral acyclovir (400 mg 5 times daily). The treatment was subsequently adjusted to include oxcarbazepine (300 mg 3 times daily) and low-intensity laser therapy (4 joules) after the lesions resolved |
| 2022 | Evaluation: Reported inadequate pain control, leading to a referral to an infectious disease specialist Revised treatment: Tas adjusted to include acyclovir (400 mg for 90 days), cashew root extract, and laser therapy (6 joules) on the ophthalmic nerve Outcome: After 3 months, the patient’s pain was reduced to zero on the VAS, with relief from the itching associated with the vesicular-bullous lesions New prescription: The patient was prescribed capsaicin (0.25 mg) combined with lidocaine 2% for local application. Oxcarbazepine was reduced to twice daily, and 4 joules of laser therapy were maintained Evaluation: Despite the combination of therapies, the patient reported insufficient pain control, with pain rated as 7 out of 10 on the VAS, leading to the addition of pregabalin (75 mg) and the reinstatement of oxcarbazepine 3 times daily |
| 2023 | Resume condition: Experienced intense spontaneous and provoked pain, necessitating an effective adjuvant therapy New treatment: Commenced an adjuvant herbal therapy with CannaMeds CBD Full Spectrum (3000 mg per 30 mL) and CannaMeds CBG Isolate (1500 mg per 30 mL), administered sublingually as prescribed Activities: Was encouraged to participate in water aerobics classes Outcome: After 15 days, the patient reported no pain, leading to the discontinuation of photobiomodulation, pregabalin, and capsaicin, and a reduction in oxcarbazepine dosage to twice daily. The patient experienced effective pain control, improved quality of life and sleep, and decreased nervousness and anxiety attacks. There were no adverse effects from the cannabis use |
| 2024 | Vaccination: The patient received the first dose of the herpes zoster vaccine and reported zero pain on the VAS |
TN: Trigeminal neuralgia; VAS: Visual Analog Scale; PHN: Postherpetic neuropathy; CBD: Cannabidiol; CBG: Cannabigerol
Discussion
For NT, initial treatment involves antiepileptic drugs; in refractory cases, invasive surgical approaches are considered.[6] In post-herpetic neuralgia, the immediate use of antivirals such as acyclovir, valacyclovir, or famciclovir is recommended, even after the first 96 h of the eruption.[8]
Chronic pain is often associated with symptoms of depressed mood, which increases refractoriness to treatment. Patients on NPH often experience a significant decrease in quality of life, accompanied by increased anxiety and sleep disturbances.[6,9] As presented by the patient in this case, in addition to worsening quality of life, her autonomy and the performance of daily, social, family, and financial activities were affected.
In 2014, the Canadian Pain Society began recommending cannabinoids as a third-level therapy for chronic neuropathic pain. Cannabinoids act mainly on G protein-coupled cannabinoid receptors, which are widely distributed throughout the body. In this way, they can modulate orofacial pain both peripherally by acting on peripheral and central trigeminal nociceptive fibers and in regions involved in endogenous analgesia mechanisms, as well as in pain perception.[10]
CBD has several therapeutic actions, including anti-inflammatory effects demonstrated by inhibiting leukocyte migration, suppressing the COX1 and COX2 pathways, and reducing the production of pro-inflammatory cytokines. In addition, its antioxidant properties provide neuroprotection. CBD also acts on serotonin receptors, providing additional anxiolytic and anti-nausea effects.[6]
With regard to adverse reactions to CBD, the majority of patients had no adverse effects and some had mild effects: dry mouth, dizziness, abdominal pain, constipation, and daytime sleepiness, but the symptoms reversed after a few days. Cannabidiol (CBD) demonstrates a more favorable safety and tolerability profile in terms of adverse effects when compared to other pharmacological agents.[9]
Studies indicate that physical activity exerts an analgesic effect through modulation of the endocannabinoid system, increasing endocannabinoid levels and promoting hypoalgesia.[10] In the case report, the patient reported clinical improvement after starting water aerobics. Although this practice promotes well-being and helps modulate pain, it is an adjuvant intervention, with no potential to replace specific pharmacological or neurological therapies.
The patient in this case did not experience any adverse effects related to the use of cannabinoids. After starting the treatment, she reported resuming her daily activities, including cleaning – an activity she greatly enjoyed – and no longer had fears about traveling due to concerns about crises. Managing the case was challenging, as the patient had been under follow-up since 2019. Although the use of cannabinoids proved effective, it is an expensive treatment, which limits the ability of many patients to afford it.
Conclusion
It is difficult to find an effective treatment for these conditions, because over time patients no longer respond to treatment. Therefore, the use of CBD and cannabigerol could be an adjuvant treatment option for patients who do not respond to conventional treatment for neuropathic pain.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Conflicts of interest
There are no conflicts of interest.
Funding Statement
Nil.
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