Final answer:
First-line treatment for a 61-year-old man with intermittent shock-like spasms of pain in his right cheek, likely due to trigeminal neuralgia, is carbamazepine, which blocks pain signals at the nerve synapses.
Step-by-step explanation:
The 61-year-old man presenting with intermittent shock-like spasms of pain in his right cheek is likely suffering from trigeminal neuralgia, a chronic pain condition that affects the trigeminal nerve. Carbamazepine is the first-line treatment for trigeminal neuralgia. It helps in reducing or blocking the pain signals at the nerve synapses. Baclofen may also be used as a secondary option or alongside carbamazepine in some cases. Botulinum toxin injections could be considered for various muscle contraction disorders and have shown to improve patients' quality of life by causing flaccid paralysis of the muscles.
However, botulinum injections are not typically the first-line treatment for trigeminal neuralgia. Diazepam is generally not used as a first-line treatment in this condition. The likely diagnosis for the 61-year-old man with intermittent shock-like spasms of pain in his right cheek is trigeminal neuralgia. The first-line treatment for trigeminal neuralgia is carbamazepine. Carbamazepine is an anticonvulsant medication that can help relieve the pain caused by the condition.