Prescribing wisely
Special populations & cautions
The right drug at the wrong dose, for too long, or in the wrong patient does harm. Three questions govern safe prescribing: for how long, in the elderly, and in pregnancy.
Duration of use
Vestibular suppressants — antihistamines, anticholinergics, benzodiazepines and dopamine antagonists — should generally be limited to 3–5 days in acute vestibular syndromes such as neuritis or labyrinthitis. Their role is to blunt disabling vertigo and nausea in the initial phase; beyond that they impede vestibular compensation, the neuroplastic process by which the brain recalibrates balance.1
Early withdrawal of suppressants and prompt start of vestibular rehabilitation therapy speeds recovery: patients who stop suppressants early and begin rehabilitation regain postural control faster than those on prolonged courses. The clinician must therefore balance acute symptom control against long-term functional outcome.1
The elderly
Older people are far more sensitive to these medicines. Sedating drugs can cause confusion, unsteadiness and falls, so they are used at the lowest dose for the shortest time — or avoided.
Age-related changes in drug handling, blood–brain barrier permeability and CNS sensitivity make the elderly high-risk. Sedatives — benzodiazepines and anticholinergics — can precipitate delirium, confusion, urinary retention and orthostatic hypotension, substantially increasing falls, hospitalisation and morbidity, compounded by polypharmacy.2
Among suppressants, meclizine and dimenhydrinate are comparatively safer at the lowest effective dose, while benzodiazepines and scopolamine should be avoided or reserved for exceptional, supervised cases. The American Geriatrics Society Beers Criteria explicitly list first-generation antihistamines and benzodiazepines as potentially inappropriate medications in older adults.3 Pair any prescribing with balance retraining and home-safety measures.
Pregnancy
Pharmacotherapy in pregnancy must weigh maternal symptom severity against fetal risk. The best-studied agents are first-generation antihistamines:
- Meclizine — FDA category B, with a long safety record in motion sickness and hyperemesis gravidarum; a reasonable first-line option for vestibular complaints in pregnancy.4
- Dimenhydrinate — also commonly used, though more sedating.
- Benzodiazepines — cross the placenta and are associated with cleft lip/palate, hypotonia and neonatal withdrawal; generally contraindicated, especially in the first trimester.5
- Anticholinergics (scopolamine) — not recommended owing to limited safety data.
Favour non-pharmacological measures — hydration, vestibular exercises, reassurance — where possible, and involve the obstetric team before starting any drug.
Key points
- Limit suppressants to 3–5 days, then start rehabilitation — prolonged use delays compensation.
- The elderly are high-risk: prefer low-dose meclizine/dimenhydrinate; avoid benzodiazepines and scopolamine (Beers Criteria).
- In pregnancy, meclizine (category B) is first-line; benzodiazepines and anticholinergics are avoided.
- Lean on non-pharmacological measures in vulnerable groups and involve the relevant specialist.