Prevalence of vitamin A deficiency. Vitamin A deficiency (VAD) is a lack of vitamin A in humans. It is common in poorer countries but rarely seen in more developed countries. Nyctalopia (night blindness) is one of the first signs of VAD.revalence of vitamin A deficiency. Vitamin A deficiency (VAD) is a lack of vitamin A in humans. It is common in poorer countries but rarely seen in more developed countries. Nyctalopia (night blindness) is one of the first signs of VAD.
Both lithium and valproate have been reported to increase rat CSF GABA levels. Regarding valproate, animal studies reported that it enhances GABA levels, GABA synaptic release, GAD activity, neuronal GABA responsiveness, and inhibits GABA-T in several brain regions.
Types of drugs that are known to interact with gabapentin and may cause problems include: 1  Opiate pain medications, including Vicodin and morphine, among others. 2  Naproxen (also known as the brands Aleve, Naprosyn, and others) 3  Medications used for heartburn, including Mylanta, Maalox, and cimetidine.