Note
Studied by 61 peoplePharmacological Management of Orofacial Pain
I. Types of Orofacial Pain
Nociceptive Pain: Caused by actual or threatened tissue damage. Common origins are odontogenic (teeth) and musculoskeletal (TMJ disorders).
Neuropathic Pain: Caused by a lesion or disease of the somatosensory nervous system. Examples include trigeminal neuralgia and burning mouth syndrome (BMS). Often involves central sensitization (CNS changes).
Nociplastic Pain: Pain without evidence of tissue damage, but with central sensitization. Fibromyalgia is a classic example; often mimics nociceptive and neuropathic pain.
Acute Pain: Short-term, associated with tissue damage.
Chronic/Persistent Pain: Long-lasting, not necessarily linked to ongoing tissue damage; more related to changes in the nervous system.
II. Pharmacological Management: Key Medications
Medication | Indication(s) | Mechanism of Action | Dosage (example) | Absolute Contraindications | Relative Contraindications | Adverse Effects |
Amitriptyline | TMD, neuropathic pain, headache disorders | Non-selective monoamine reuptake inhibitor; blocks Na+, K+, Ca2+ channels; enhances GABA. | 10-25mg OD (PM) | Heart block, MI aftermath, arrhythmias, bipolar mania, hypersensitivity | Diabetes, epilepsy, bipolar disorder, liver disease, hyperthyroidism, glaucoma, suicide risk. Careful use in elderly or those with cardiovascular disease. | Drowsiness, xerostomia, blurred vision, increased ocular pressure, urinary retention |
Nortriptyline | TMD, neuropathic pain | Inhibits noradrenaline reuptake; blocks Na+, K+, Ca2+ channels. | 10-25mg OD (PM) | Heart block, MI aftermath, arrhythmias, bipolar mania, hypersensitivity | Similar to Amitriptyline | Drowsiness (less than amitriptyline), xerostomia, increased appetite |
Gabapentin | Neuropathic pain, TMD | Interacts with α2δ Ca2+ channels; increases GABA synthesis & release. | Initially 300mg OD | Hypersensitivity | Diabetes, psychotic illness, substance dependence, seizures, low weight, pregnancy, elderly, respiratory compromise, neurological disease. | Confusion, weight gain, xerostomia, constipation, diarrhea, visual impairment, hypertension. Risk of substance misuse. |
Pregabalin | Neuropathic pain | Binds to Ca2+ channels; reduces Ca2+ influx; decreases neurotransmitter release (glutamate, substance P). | 150mg daily | Hypersensitivity | Epilepsy, glaucoma, hepatic or renal conditions, psychiatric illness, uncontrolled hypertension, substance dependence. | Confusion, weight gain, xerostomia, constipation, diarrhea, visual impairment, hypertension. Risk of substance misuse. |
Duloxetine | Neuropathic pain | Inhibits serotonin & norepinephrine reuptake. | 20-30mg OD (titrate) | Epilepsy, glaucoma, hepatic or renal impairment, psychiatric illness, uncontrolled hypertension, hypersensitivity | Elderly, hypovolemic patients, bleeding disorders, cardiac conditions | Nausea, vomiting, cardiovascular effects, hypertension, sexual dysfunction, hepatic damage |
Carbamazepine | Trigeminal neuralgia (first-line) | Na+ and Ca2+ channel blocker; metabolite limits repetitive neuronal firing. | 100mg OD-BD | Acute porphyrias, AV conduction abnormalities, bone marrow depression, hypersensitivity, HLA-B*1502 allele | Cardiac conditions, bleeding disorders, skin reactions, glaucoma, seizures, liver disease. | Weight gain, nausea, vomiting, dizziness, drowsiness, xerostomia, fatigue, blood abnormalities, SJS/TEN. |
Oxcarbazepine | Trigeminal neuralgia | Blocks Na+ channels. | 150mg OD (titrate) | Acute porphyrias, heart failure, cardiac conduction abnormalities, hyponatremia, hypersensitivity, HLA-B*1502 allele | Liver and renal impairment, breastfeeding, pregnancy. | Abdominal pain, nausea, dizziness, drowsiness, emotional liability, impaired concentration, SJS/TEN. |
Baclofen | Trigeminal neuralgia, TMD | GABAB receptor agonist; decreases neurotransmitter release; increases K+ conductance. | 5mg TDS (titrate) | Active peptic ulceration, hypersensitivity | Cardiovascular disease, diabetes, epilepsy, history of peptic ulcers, Parkinson’s disease, respiratory impairment. | Confusion, xerostomia, hypotension, nausea, dizziness, drowsiness, headaches. |
Lamotrigine | Trigeminal neuralgia | Na+ and Ca2+ channel blocker; stabilizes neuronal membranes; decreases glutamate; enhances GABAergic transmission | 25mg OD (titrate) | Hypersensitivity | Parkinson's disease, myoclonic seizures, hepatic/renal impairment. | Drowsiness, fatigue, nausea, headaches, xerostomia, agitation, sleep disorders, SJS/TEN. |
Alpha-Lipoic Acid | BMS | Antioxidant. | 200mg TDS | Hypersensitivity | Possible interactions with cisplatin, cyclophosphamide, gentamicin, and amikacin. | Low blood sugar, vision changes (rare), urticaria (rare). |
Lidocaine HCl | Acute rescue (trigeminal neuralgia), post-herpetic neuralgia | Amino-amide local anesthetic; reduces Na+ influx. | Topical application | Hypersensitivity | Inflamed/infected tissues, avoid near middle ear. | Hypotension, edema, irritation, nausea, vomiting, numbness, tingling, drowsiness, tremor, arrhythmia, methemoglobinemia |
Benzydamine HCl | Inflammatory conditions (oral) | Weak inhibitor of prostaglandin & TNF-α synthesis; membrane stabilizer. | 0.15% mouthwash | Hypersensitivity | Potential systemic interactions. | Angioedema, photosensitivity, respiratory disorders, skin reactions. |
Capsaicin | BMS | Activates TRPV1 receptors; depletes substance P. | Topical application | None known | Caution with hypertension or recent cardiovascular events. | Burning, abnormal sensations to the area of skin applied. |
Clonazepam | BMS | Enhances GABA activity. | 500µg, dissolve in mouth | Myasthenia gravis, acute pulmonary insufficiency, neuromuscular respiratory weakness, alcohol/drug dependence, respiratory depression, hypersensitivity | Personality disorders, elderly (reduced dose). | Drowsiness, increased oral burning, xerostomia. |
III. Additional Considerations
Medication Overuse Headache: Regular use of simple analgesics (paracetamol, NSAIDs) or codeine can lead to this condition.
Simple Analgesia: Paracetamol is usually first-line for acute, mild-to-moderate pain; NSAIDs (like ibuprofen) may be added if needed. Opioids are considered for short-term use only and usually as a last resort.
Combination Analgesics: Combining different analgesics (e.g., paracetamol and ibuprofen) may be more effective than using a single agent.
Off-label Prescribing: Many of the drugs are prescribed "off-label" for orofacial pain, meaning not specifically licensed for the condition. It is crucial for clinicians to document this, justify the rationale, and inform the patient.
Drug Interactions: Be aware of potential interactions with other medications a patient may be taking.
Driving: Many medications can impair cognitive function and driving ability; inform patients of the risks and requirements for reporting to driving regulatory bodies (like the DVLA in the UK).
Biopsychosocial Approach: A holistic approach is vital, including psychological and social factors in addition to the physical aspects.
Tapering Medications: When discontinuing long-term medications, especially those with dependence potential, gradually reduce the dose over several weeks to minimize withdrawal symptoms.