Bromides have been used to treat epilepsy for over 100 years. They are still used occasionally in severe cases, especially in children with underlying brain damage. Bromides have traditionally been given in a solution consisting of sodium, potassium and ammonium salts of bromide in equal amounts (by weight) of each. The usual preparation contains 1200 mg (400 mg of each salt) in 5 mL.
The base can be a syrup and water mix. A one month expiry date and refrigeration is suggested.

Recommended doses: children less than 6 years: 300 mg BD to 600 mg TID
children 6 years and older: 300 mg to 1000 mg TID

The half-life of bromide is about 12 days therefore steady state is not reached for about one month. Toxicity (bromism) can occur and plasma concentrations of bromide should be monitored. Increased sodium intake increases bromide clearance and vice-versa.
Nahata and Hipple (Pediatric Drug Formulations 4 th edition) describe Three Bromides Mixture prepared in a base of Ora-Plus. They suggest that this is stable for 12 months but state that this is based on experience rather than stability testing.

References
Levy R et al (eds) Antiepileptic Drugs, 3rd Ed. Raven Press, New York, 1989.
Martindale 31st Edition.