Final answer:
The first-line drug choice for treating Trigeminal Neuralgia is Carbamazepine, which is an anticonvulsant that directly targets the neuropathic pain mechanism of the disease.
Step-by-step explanation:
The first choice for drug therapy in treating Trigeminal Neuralgia (TN), which is a form of neuropathic pain, is Carbamazepine. This medication is an anticonvulsant that is effective in alleviating the pain associated with TN by stabilizing neural membranes and reducing the nerve impulse transmission which triggers the pain. Unlike acetaminophen, which is typically used for osteoarthritis (OA) and carries a lower risk of serious side effects when used as prescribed, or non-steroidal anti-inflammatory drugs (NSAIDs) that may be associated with gastrointestinal bleeding and other risks, Carbamazepine targets the neuropathic pain mechanism directly. Opioids, such as Morphine, are usually reserved for when other medications fail or serious side effects occur, due to the risks of addiction and recommendation for short-term use. Gabapentin, another anticonvulsant, is also commonly used for neuropathic pain but may be considered as an alternative if Carbamazepine is not suitable or ineffective.