Caution should be exercised in people who have narcolepsy in comorbidity with postural orthostatic tachycardia syndrome (POTS). Modafinil, like other centrally acting stimulants prescribed for people with narcolepsy, increases POTS-related autonomic dysfunction and results in tachycardia/arrhythmia side effects in people with cardiovascular risk factors. Sodium oxybate, a metabolite of GABA, is a CNS depressant which makes it an alternative drug for stimulant-intolerant people with POTS.