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by Deborah H. Clark, RPh, FACVP, PCCA Clinical Compounding Pharmacist
Several post infection complications have been linked with SARS-CoV-2 (COVID-19) since the beginning of the 2020 pandemic. In addition to known effects on the respiratory-system, other complications can manifest in other organ systems such as the cardiovascular, gastrointestinal and neurologic systems post COVID-19 infection.1
Neurologic manifestations were widely reported and include anosmia (loss of smell), encephalopathy, encephalitis, headaches, vertigo, dizziness, Guillain-Barré syndrome, meningitis and stroke. Authors of a case study discussing the onset of vertigo in a post-COVID-19 patient defined vertigo “as a false sense of movement brought by the asymmetry in the vestibular system due to damage to the labyrinth, vestibular nerve, or central vestibular system of the brainstem or the cerebellum. Depending on the location of the pathology, it is classified as peripheral vertigo (vestibular components) or central vertigo (brain).”2
There are several studies that examined the role of viral infections in vertigo pathogenesis. Viruses that were studied included Epstein-Barr, cytomegalovirus, rubella, adenoviruses, influenza A & B and herpes simplex. Many of the studies propose direct vestibular nerve infection as a possible mechanism and potential cause of vestibular neuritis.3 A novel link between COVID-19 and newly diagnosed tinnitus, vertigo, hearing loss and otalgia was reported; however, this link has not been fully elucidated and requires further study.4
Nevertheless, some studies reported an association between recent COVID-19 infection and newly diagnosed vestibular neuritis. Vestibular neuritis is a benign, self-limiting condition normally presenting with vertigo, nausea, vomiting and gait abnormality. It is thought to be due to viral or post-viral inflammation of the vestibular component of the eighth cranial nerve.2 Patients who developed acute vertigo symptoms post-COVID 19 infection reported symptoms that lasted varying periods after their COVID recovery.
In addition to previously mentioned studies, there have been several case reports of patients entering the emergency room complaining of new onset vertigo associated with previous SARS-CoV-2 infection, with or without nausea and vomiting.1-3 These patients did not have any previous history of ear disease. Most of these patients were managed with either anti-vertigo agents, antihistamines, IV fluids or anti-nausea agents.
In one case, a 64-year-old patient reported to the emergency department with acute vertigo and without nausea and vomiting. The patient had a 9-day history of fever, cough, runny nose, dyspnea, myalgia and fatigue. After the patient was stabilized and several diagnostic tests performed, it was determined the patient had no neurologic or auditory disorders. The patient also reported contact with a confirmed COVID-19 patient who lived nearby. From the patient’s history of symptoms and lab confirmation, it was determined the patient was infected with SARS-CoV-2, which the practitioner determined to be the cause of vertigo. The physician prescribed betahistine 24mg daily as anti-vertigo medication. The patient was also prescribed other medications to treat COVID-19. The patient returned one month after recovering from COVID-19, reporting improvement of vertigo but not complete resolution. The physician continued betahistine therapy for a total of three months; vertigo resolved a month and a half after COVID-19 recovery.1
Another study discussed a patient who reported to the ER with vertigo, nausea and vomiting lasting for three hours. As with the previous case, the patient had a history of COVID-19 infection. The patient was tested for neurological and auditory deficits and none were found. The patient was treated with ondansetron and IV fluids to control nausea and vomiting. The patient’s vertigo was managed with betahistine 16mg and an antihistamine. The patient subsequently reported complete resolution of symptoms within seven days.2
Betahistine dihydrochloride is a structural analog of histamine, a weak agonist of H1 receptors and antagonist of H3 receptors. It is approved for use in the treatment of Ménière’s disease and symptoms of vertigo in more than 115 countries.
In animal models of vestibular dysfunction, betahistine was observed to improve vestibular compensation by increasing blood flow in the vestibulocochlear region and decreasing the excitatory response in vestibular cells by blocking the H3 receptor cells locally. Several clinical trials have shown that betahistine improved vertigo-related symptoms — including nausea and vomiting — and effectively reduced the frequency and severity of vertigo.5
Betahistine dihydrochloride is not commercially manufactured in the United States. Therefore, it must be compounded for patients. Compounding pharmacists may formulate this API in a capsule to meet a patient’s need. For example, PCCA Formula #10963 – Betahistine Dihydrochloride 16mg Capsules Size #1 (LoxOral®) — is an example of a formula that may be used to help patients with COVID-19-related vertigo.
Members with clinical services access may contact our Clinical Services team to discuss compounding betahistine for COVID-19 and other compounding-related concerns.