Nimodipine in otolaryngology: from past evidence to clinical perspectives.

As L-type voltage-gated calcium channels (VGCCs) control Ca(2+) influx and depolarisation of cardiac and vascular smooth muscle, they represent a specific therapeutic target for calcium channel blockers (CCBs), which are approved and widely used to treat hypertension, myocardial ischaemia and arrhythmias. L-type currents also play a role in calcium entry in the sensory cells of the inner ear. In hair cells of both cochlea and labyrinth, calcium cytoplasmic influx is the first physiological process that activates complex intracellular enzymatic reactions resulting in neurotransmitter release. Excessive calcium ion entry into sensory cells, as a consequence of L-VGCCs malfunction is responsible for over-activation of phospholipase A2 and C, protein kinase II and C, nitric oxide synthase and both endonucleases and depolymerases, which can cause membrane damage and cellular death if the cytoplasmic buffering capacity is overcome. Nimodipine, a highly lipophilic 1-4 dihydropyridine that easily crosses the brain-blood barrier, is generally used to reduce the severity of neurological deficits resulting from vasospasm in patients with subarachnoid haemorrhage. Moreover, due to its selective blocking activity on L-channel calcium currents, nimodipine is also suggested to be an effective countermeasure for cochlear and vestibular dysfunctions known as channelopathies. Indeed, experimental data in amphibians and mammalians indicate that nimodipine has a stronger efficacy than other CCBs (aminopyridine, nifedipine) on voltage-dependent whole-cell currents within hair cells at rest and it is the only agent that is also effective during their mechanically induced depolarisation. In humans, the efficacy of nimodipine is documented in the medical management of peripheral vestibular vertigo, sensorineural hearing loss and tinnitus, even in a pathology as complex as Ménière's disease. Nimodipine is also considered useful in the prophylaxis of damage to the facial and cochlear nerves caused by ablative surgery of cerebellopontine tumours; it has been recently hypothesised to accelerate functional recovery of recurrent nerve lesions during thyroid cancer surgery. Further trials with adequate study design are needed to test the efficacy of nimodipine in the treatment of vertigo due to cerebrovascular disease and vestibular migraine.

Effect of a fixed combination of nimodipine and betahistine versus betahistine as monotherapy in the long-term treatment of Ménière's disease: a 10-year experience.

Despite an abundance of long-term pharmacological treatments for recurrent vertigo attacks due to Ménière's disease, there is no general agreement on the their efficacy. We present the results of a retrospective study based on a 10-year experience with two long-term medical protocols prescribed to patients affected by Ménière's disease (diagnosed according to the American Academy of Otolaryngology-Head and Neck Surgery Committee on Hearing and Equilibrium guidelines) who completed treatments in the period 1999-2009. A total of 113 medical records were analysed; 53 patients received betahistine-dihydrochloride at on-label dosage (32 mg die) for six months, and 60 patients were treated with the same regimen and nimodipine (40 mg die) as an add-therapy during the same period. Nimodipine, a 1,4-dihydropyridine that selectively blocks L-type voltage-sensitive calcium channels, has previously been tested as a monotherapy for recurrent vertigo of labyrinthine origin in a multinational, double-blind study with positive results. A moderate reduction of the impact of vertigo on quality of life (as assessed by the Dizziness Handicap Inventory) was obtained in patients after therapy with betahistine (p < 0.05), but a more significant effect was achieved in patients treated by combined therapy (p < 0.005). In the latter group, better control of vertigo was seen with a greater reduction of frequency of attacks (p < 0.005). Both protocols resulted in a significant improvement of static postural control, although a larger effect on body sway area in all tests was obtained by the fixed combination of drugs. In contrast, no beneficial effect on either tinnitus annoyance (as assessed by the Tinnitus Handicap Inventory) and hearing loss (pure-tone average at 0.5, 1, 2, 3 kHz frequencies of the affected ear) was recorded in patients treated with betahistine as monotherapy (p > 0.05), whereas the fixed combination of betahistine and nimodipine was associated with a significant reduction of tinnitus annoyance and improvement of hearing loss (p < 0.005). It was concluded that nimodipine represents not only a valid add-therapy for Ménière's disease, and that it may also exert a specific effect on inner ear disorders. Further studies to investigate this possibility are needed.