Brief Answer:
Dizitac may cause such side effect.

Detailed Answer:
Hello,
I am Dr Dhananjay Chavan, MD. I am a geriatric psychiatrist.
Dizitac contains dimenhydrinate and cinnarizine. Both are antihistamines. Dimenhydrinate has anti-cholinergic properties too. Therefore it is used with caution in the elderly.
Dizziness is a common side effect of dimenhydrinate. Seizures is also a known side effect.
Cinnarizine sometimes causes acute extrapyramidal side effects. Up-rolling eyes may be a part of this acute side effect. It is commoner in elderly women.
Both these medications are to be used with caution in the elderly.
Vertin which was the medication prescribed first is known to cause headache. But otherwise it is probably associated with lesser side effects.
Even assuming that there is not much to choose between efficacy of these two medications, in my opinion, it would be better to stick to Vertin. This is because Dizitac is actually a combination of two medications. General principle and especially important in the elderly is to avoid multiple medications. You may start with Vertin 8 mg thrice a day and see how it affects your mother. If she is drowsy, she should not drive car. It is possible that she will not to be too drowsy on 8 mg of Vertin. It is worth a try. Give it regularly. The vertigo that you describe has a tendency to come in waves or clusters. She may not need the medication for long.
Two more important tips:
1. Simple exercises for vertigo are quite helpful and come without side effects! You may find these on youtube. Try very gently at first. (You may also consult a physiotherapist or a Ear Nose Throat specialist or a Neurologist to learn this simple exercises. But these are easily found on the net).
2. Encourage your mother to step out of the house regularly. Elderly run the risk of becoming increasingly afraid of falls or other accidents outside; and thus become housebound. They must remain active for psychological reasons as well.
I hope I have answered your question. If you have any further queries, I will be happy to help.

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Brief Answer:
Stop Stemetil. Continue Vertin for a few days.

Detailed Answer:
You should stop Stemetil as it has several side effects. It acts on Central Nervous System. Once Vertin takes care of Vertigo, nausea will also decrease. No need, if we can avoid, of yet another medicine for nausea.
If at all needed, Domperidone is a better option than Stemetil for nausea as it has far lesser action on central nervous system.
You should continue Vertin for a couple of more days at least even after she feels completely normal - free of vertigo. After that, if Vertigo recurs, you can always restart Vertin.
If you do not have any clarifications, you may close the discussion and rate the answer. Wish you good health. Take care.

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