Phendimetrazine (Bontril, Adipost, Anorex-SR, Appecon, Melfiat, Obezine, Phendiet, Plegine, Prelu-2, Statobex) is a stimulant drug of the morpholine chemical class used as an appetite suppressant. Pharmacology
Phendimetrazine functions as a prodrug to phenmetrazine; approximately 30 percent of an oral dose is converted into it. Phendimetrazine can essentially be thought of as an extended-release formulation of phenmetrazine with less potential for abuse. Phendimetrazine is an anorectic drug which acts as a norepinephrine-dopamine releasing agent (NDRA).As an amphetamine congener, its structure incorporates the backbone of methamphetamine, a potent CNS stimulant. While the addition of an N-methyl group to  amphetamine significantly increases its potency and bioavailability, methylation of phenmetrazine renders the compound virtually inactive. However, phendimetrazine is a prodrug for phenmetrazine which acts as the active metabolite. Phendimetrazine possesses preferable pharmacokinetics over phenmetrazine as a therapeutic agent because its metabolization by demethylases produces a more steady and prolonged exposure of active drug within the body. This decreases abuse potential as the peak blood-concentration of active phenmetrazine thats produced from a single dose of phendimetrazine is lower than a single therapeutically equivalent dose of phenmetrazine. Indicated as a short-term secondary treatment for exogenous obesity, phendimetrazine immediate-release 35mg tablets are typically consumed one hour before meals, not to exceed three doses daily. Phendimetrazine is also manufactured as a 105mg extended-release capsule for once daily dosing, typically consumed 30 to 60 minutes before a morning meal. Whereas the immediate-release formulation has a maximum daily dosage of 210mg (6 tablets), the extended-release capsules have a maximum daily dosage of 105mg (one capsule).
It may present with bilaterally symmetrical symptoms, or asymmetrically, with one ear developing the condition after the other or not at all. The time frames for progress of the disease vary greatly and symptoms of hearing loss may be temporary or permanent.The vestibule and semi-circular canal are inner-ear components that comprise the vestibular system. Together they detect all directions of head movement. Two types of otolith organs are housed in the vestibule: the saccule, which points vertically and detects vertical acceleration, and the utricle, which points horizontally and detects horizontal acceleration. The otolith organs together sense the heads position with respect to gravity when the body is static; then the heads movement when it tilts; and pitch changes during any linear motion of the head. The saccule and utricle detect different motions, which information the brain receives and integrates to determine where the head is and how and where it is moving. The semi-circular canals are three bony structures filled with fluid. As with the vestibule, the primary purpose of the canals is to detect movement. Each canal is oriented at right angles to the others, enabling detection of movement in any plane. The posterior canal detects rolling motion, or motion about the X axis; the anterior canal detects pitch, or motion about the Y axis; the horizontal canal detects yaw motion, or motion about the Z axis. When a medication is toxic in the vestibule or the semi-circular canals, the patient senses loss of balance or orientation rather than losses in hearing.