Moderate
Alprazolam × citalopram
Benzodiazepines. Short-to-medium-acting anxiolytics×SSRI (selective serotonin reuptake inhibitor)
Mechanism
Additive CNS depression. Citalopram does not inhibit CYP3A4 — no pharmacokinetic interaction with alprazolam. The effect adds up at GABA and serotonin receptors.
Symptoms
Sedation, fatigue, slowed reactions, impaired coordination. In older patients: fall and fracture risk. Driving and operating machinery: accident risk.
Management
On starting the combination, begin alprazolam at the minimum dose. In older patients, cap citalopram at 20 mg/day (QT risk) and alprazolam at 0.5 mg/day. For long-term anxiety treatment, plan CBT as the core therapy with gradual benzodiazepine taper.