DRUG DESCRIPTION. NAMENDA XR is an orally active NMDA receptor antagonist. The chemical name for memantine hydrochloride is 1-amino-3,5-dimethyladamantane hydrochloride with the following structural formula: The molecular formula is C12H21Nâ¢HCl and the molecular weight is 215.76.
There are three main parts to the ear, including the inner ear, middle ear and outer ear. In order for hearing to occur, there is a sequence of actions that must occur to transform waves of sound in the air into electrical impulses. These impulses are transmitted to the brain by the auditory (hearing) nerve.
With the middle ear acting as an impedance-matching device, a majority of the energy of a sound wave moves on to the inner ear. In the case of a sound that is too loud, muscles attached to the ossicles can tense to decrease the proportion of the sound that is transferred and help to prevent damage to the inner ear. Connecting the middle ear to the throat s a short, narrow passage called the eustachian tube (Figure 1).