I need to ask few more questions before answering your query. Early consultations can prevent complications. Kindly contact me on whatsapp chat  (84960595 six five) Dr Faisal Zoheb MBBS , MD PAEDIATRICS , PGPN (BOSTON), FELLOWSHIP IN NEONATOLOGY ( Newborn and vaccination specialist )

Not to be used for kids

Make the child seat in front and avoid screen use .

Greetings Promethazine , are generally restricted or contraindicated for young children due to risks of severe side effects. Safer alternatives for motion sickness in young children include specific liquid antihistamines or dimenhydrinate. Non-medicinal strategies, such as keeping the car cool and encouraging the child to look ahead, can also be effective.

Don’t use anything

No need if avoidable

Instead of medicines, can use alternative methods like sitting in front ,avoiding screen