Interferon beta-1b is a cytokine in the interferon family used to treat the relapsing-remitting and secondary-progressive forms of multiple sclerosis (MS). It is approved for use after the first MS event. Closely related is interferon beta 1a, also indicated for MS, with a very similar drug profile. Mechanism of action
Interferon beta balances the expression of pro- and anti-inflammatory agents in the brain, and reduces the number of inflammatory cells that cross the blood brain barrier. Overall, therapy with interferon beta leads to a reduction of neuron inflammation. Moreover, it is also thought to increase the production of nerve growth factor and consequently improve neuronal survival. Side effects
Interferon beta-1b is available only in injectable forms, and can cause skin reactions at the injection site that may include cutaneous necrosis. Skin reactions vary greatly in their clinical presentation. They usually appear within the first month of treatment albeit their frequence and importance diminish after six months of treatment. Skin reactions are more prevalent in women. Mild skin reactions usually do not impede treatment whereas necroses appear in around 5% of patients and lead to the discontinuation of the therapy. Also over time, a visible dent at the injection site due to the local destruction of fat tissue, known as lipoatrophy, may develop. Interferons, a subclass of cytokines, are produced in the body during illnesses such as influenza in order to help fight the infection. They are responsible for many of the symptoms of influenza infections, including fever, muscle aches, fatigue, and headaches.
Conductive hearing loss (CHL) occurs when there is a problem transferring sound waves anywhere along the pathway through the outer ear, tympanic membrane (eardrum), or middle ear (ossicles). If a conductive hearing loss occurs in conjunction with a sensorineural hearing loss, it is referred to as a mixed hearing loss. Depending upon the severity and nature of the conductive loss, this type of hearing impairment can often be treated with surgical intervention or pharmaceuticals to partially or, in some cases, fully restore hearing acuity to within normal range. However, cases of permanent or chronic conductive hearing loss may require other treatment modalities such as hearing aid devices to improve detection of sound and speech perception. Causes
Common causes of conductive hearing loss include:

External ear
Cerumen (earwax) or foreign body in the external auditory canal
Otitis externa, infection or irritation of the outer ear
Exostoses, abnormal growth of bone within the ear canal
Tumor of the ear canal
Congenital stenosis or atresia of the external auditory canal (narrow or blocked ear canal). Ear canal stenosis & atresia can exist independently or may result from congenital malformations of the auricle such as microtia or anotia. Acquired stenosis (narrowing) of the external auditory canal following surgery or radiotherapy

Middle ear
Fluid accumulation is the most common cause of conductive hearing loss in the middle ear, especially in children. Major causes are ear infections or conditions that block the eustachian tube, such as allergies or tumors.