Is 20g of cyclobenzaprine too much in one night? If you just started taking it?

I've taken 20 mg a few times as I suffer from back pain. make sure you have plenty of sleep time as it will likely make you drowsy, if you don't get enough sleep you'll wake up groggy and need an energy drink to get you going

Usual Adult Dose for Muscle Spasm
Initial dose: 5 mg orally 3 times a day.
Based on individual patient response, the dose may be increased to either 7.5 mg or 10 mg 3 times a day.

Alternate doses include the 15 mg extended release capsule or 30 mg extended release capsule orally once a day.

Usual Geriatric Dose for Muscle Spasm
Because most muscle relaxants and antispasmodic drugs can cause anticholinergic adverse events, sedation, and weakness, and because their effectiveness at doses tolerated by elderly people is questionable, cyclobenzaprine meets the Beers criteria as a medication that is potentially inappropriate for use in older adults.

The manufacturer suggests an initial dose in the elderly of 5 mg, titrating slowly upward based on individual patient response.

Extended release formulations are not recommended for use in elderly patients.

Usual Pediatric Dose for Muscle Spasm
Pediatric patients 15 years of age and older:
Initial dose: 5 mg orally 3 times a day.
Based on individual patient response, the dose may be increased to either 7.5 mg or 10 mg 3 times a day.

Renal Dose Adjustments
Data not available

Liver Dose Adjustments
Mild hepatic impairment:
Immediate release: Initial dose: 5 mg, titrating slowly upward
Extended release: Not recommended

Moderate to severe hepatic impairment:
Not recommended

Precautions
Safety and effectiveness have not been established in pediatric patients less than 15 years of age.

Dialysis
Data not available

Other Comments
Use of cyclobenzaprine for periods longer than 2 to 3 weeks is not generally recommended.

https://www.drugs.com/dosage/cyclobenzaprine.html

Always consult with your Dr. first.-