hi, I have read your question, You are experiencing one of the less serious side effects of Quinine , Generally this effect lasts for about 3-4 days after the discontinuation of the drug . You have not mentioned your age , Tinnitus (ringing in the ear) sometimes could affect to the people 60 and above .Tinnitus (=rinnging in the ear ) is not a disease, but a condition that can result from a wide range of underlying causes: neurological damage (multiple sclerosis), ear infections, oxidative stress,[1] foreign objects in the ear, nasal allergies that prevent (or induce) fluid drain, wax build-up and exposure to loud sounds. Withdrawal from benzodiazepines may cause tinnitus as well. In-ear earphones, whose sound enters directly into the ear canal without any opportunity to be deflected or absorbed elsewhere, are a common cause of tinnitus when volume is set beyond moderate levels. Tinnitus may be an accompaniment of sensorineural hearing loss or congenital hearing loss, or it may be observed as a side effect of certain medications. However, the most common cause is noise-induced hearing loss. If this issue persists I suggest you to consult an ENT specialist nearby. Wishing you a good health, DR.G.Gayatri devi.