Chronic
orofacial pain is a rapidly evolving and challenging field that deals with the management of
pain originating from neurogenic, osseous, muscular, or vascular structures of the head and neck. The challenge lies in the accurate diagnosis of
orofacial pain conditions, which may be difficult to differentiate in many clinical situations. As
pain cannot be "seen" or precisely located or its intensity measured with any device, clinicians must rely heavily on the patient's own description of type, duration and location of
pain, and thus, history plays a crucial role in diagnosis. Advances in neuroscience, pharmacology, and
pain management have made medications one of the primary therapeutic modalities in the management of
pain including
orofacial pain conditions. Despite this, these medications will not help patients if the origin and nature of
pain is not accurately diagnosed. Hence, diagnosis is critical for successful management of
orofacial pain conditions. Experience and knowledge of practice in
pain management have led clinicians to devise several clinical diagnostic tests using medications in various forms (topical, oral,
injections, intravenous infusions) to differentiate certain
orofacial pain disorders where the nature of
pain is unclear and the presentation of
pain is at multiple sites. Although the diagnostic tests are not 100 percent accurate, they are very effective in many clinical scenarios, especially in
orofacial pain conditions. Topical medications such as
anesthetics and
anti-inflammatories, oral medications such as anti-inflammatory drugs and
skeletal muscle relaxants,
injections such as
local anesthetics and
corticosteroids, and vapocoolant sprays are some examples of the modalities used by clinicians to manage
orofacial pain conditions. These medications may also be used for diagnostic tests to aid in accurate diagnosis of some
orofacial pain conditions. In addition, there are special cases where medications such as
triptans,
carbamazepine and
indomethacin may be used as diagnostic tests to confirm diagnosis of
migraines,
neuralgias, or stabbing
headaches, respectively. Based on the concept of using medications to predict which treatment would be best for certain
pain conditions or to aid in better diagnosis, diagnostic
intravenous infusions of
lidocaine,
morphine, and
ketamine have been studied to test the response to adjuvant
analgesics and oral
dextromethorphan. Paradoxically, taking the patients off their current medications can be of diagnostic significance in conditions like
medication overuse headache and
serotonin selective reuptake inhibitor-induced clenching. In summary, this paper focuses on the use of medications in different forms as useful diagnostic tests for differential diagnosis of
orofacial pain conditions that are difficult to diagnose or are refractory to past or current treatment.