Welcome @miep, I'm sorry to hear that you had an adverse effect from the Pfizer vaccine. Hopefully members who have tried Clonazepam for BFS can share their experience with you. I did a search of Connect and only found one mention in this discussion by @captainanxiety8 here - https://connect.mayoclinic.org/comment/616427/. He shared another post on things that helped his BFS here - https://connect.mayoclinic.org/comment/312187/.

Here is some information I found on BFS that you might find helpful.

"Treatment for Fasciculations
Although some control of severe fasciculations can be achieved with beta-blockers and anti-seizure medications, no drug has ever been shown to alleviate the symptom consistently.

One of the most effective means of controlling BFS is relaxation and anxiety management. Anxiety has a cause-and-effect relationship with fasciculation; it can trigger an episode and aggravate its severity once it starts.

If anxiety is severe, it is best to seek help from a psychologist or psychiatrist who can provide stress-reduction training or prescribe anti-anxiety drugs if needed. Stimulants like caffeine should also be avoided."
-- Benign Fasciculation Syndrome: Causes and Treatment: https://www.verywellhealth.com/benign-fasciculation-syndromes-2488771

Did you report your adverse reaction to the COVID vaccine to VAERS ? - https://vaers.hhs.gov/reportevent.html

I developed peripheral neuropathy after the Pfizer vaccine. My symptoms include muscle fasciculations and spasms (in the beginning). The first medication I received was clonazepam, but I couldn't tolerate it. Fortunately, I eventually found the Neuro V Long-Haulers Facebook group. There are many members suffering from BFS associated with the Covid vaccines. There is a Danish physician who is helping us. His recommendations include a dietary supplement called palmitoylethanolamide (PEA) to reduce neuroinflammation. It is helping my nerve pain and fatigue. It might help with BFS. I recommend joining that group.

My twitches started after my vaccine too (about a year ago). I’m not sure if this is a link, but the only thing I can attribute it to. I was just recently diagnosed with CFS. However, I haven’t really had any cramps- just twitching everywhere randomly.

Lately, the twitches have been getting worse and my left leg has just felt ‘off’. Praying it doesn’t get worse or was a misdiagnosis. I do believe that my anxiety is contributing to the worsening symptoms.

I am also new to this group and was amazed at the amount of people, who suffer from this! This is new for me since February and I feel like my BFS is a result of the 3rd Moderna vaccine. I’ve been tested, poked, prodded and shocked (EMG), MRI from Brain to Lumbar spine, DNA complete genome test and ION micro nutrient tested. I’ve had zoom calls with the top neurologist in Tel Aviv and the Clevelend Clinic. Upon studying my full reports, they found nothing. I should be happy I suppose, that the bad diseases are ruled out, but this isn’t pleasant either! I’ve tweaked my supplements ( NAC, Mg, CoQ10, Omega 3, Glutathione, B12, Turmeric, Nicotinamide, Selenium, Iodine) 10 times, changed my BP meds and got off of the low dose of Nortryiptyline, I was taking for migraines. Nothing helps and I feel like Benadryl and melatonin make it worse. I cannot stop my Crestor as I have a stent in my LAD. Not sure if Crestor could be the culprit. Other generic Rosuvastatins caused muscle tremors initially, until I started taking Crestor. But Crestor is also Rosuvastatin, I don’t know. I would love to have one night’s sleep without waking from this. My neurologist prescribed Gabapentin, but that made it worse and the thought of trying Lyrica just scares me. I drink 2 liters of H2O daily and take probiotics, electrolytes plus extra 1000mg combo magnesium supplements. I eat healthy and watch my diet carefully. Does anyone have any other suggestions?