Drug-induced dizziness is a common adverse drug effect. The patient may experience any of 4 basic sensations (subtypes): vertigo (a spinning sensation or false sense of motion), disequilibrium (feeling wobbly or off-balance), presyncope (a feeling of impending loss of consciousness, which may lead to true syncope), or lightheadedness (feeling of disconnect with environment). These symptoms can be indistinct and occur together. Any of these may be accompanied by other symptoms, including nausea or mental fogginess.

While many drugs may be implicated in causing dizziness (see Drug Reaction Data below), the following are the most frequent culprits:

• Aminoglycoside antibiotics (gentamicin, streptomycin) and other ototoxic drugs (eg, cisplatin) may induce vertigo or disequilibrium.
• Antihypertensive and diuretic drugs may cause lightheadedness and presyncope by mechanism of inducing postural hypotension and reduced cerebral blood flow.
• Anticonvulsant drugs (carbamazepine, phenytoin, primidone) and alcohol may cause acute (reversible) disequilibrium or chronic (irreversible) disequilibrium, resulting from cerebellar dysfunction.
• Sedating drugs (barbiturates, benzodiazepines, and tricyclic antidepressants) can cause a nonspecific dizziness that is possibly related to central nervous system depression.
• Several drugs can produce a distinctive drug-intoxication syndrome, presenting with disorientation, memory and cognitive impairments, gaze-evoked nystagmus, and gait disturbances. This is especially important to distinguish from drug-induced dizziness as it can be confused with more serious conditions.
• Alcohol may cause central nervous system (CNS) depression and cerebellar toxicity, which may result in dizziness from ingestion.