cns depression
15 interactions related to cns depression
diazepam + kava
Kava's kavalactones act on the GABA-A receptor, the same system diazepam enhances, so combining them produces additive central nervous system depression and excessive sedation. A published case report describes a man who became semicomatose within days of adding kava to a benzodiazepine. Kava also carries a separate, documented liver-safety signal.
lorazepam + valerian
Valerian root contains valerenic acid and related compounds thought to modulate GABA-A receptor activity. Lorazepam is a benzodiazepine that also enhances GABA signaling. Taking them together may produce additive central nervous system depression, with a theoretical increase in drowsiness, slowed thinking, and impaired coordination. The interaction is mechanism-based and flagged as a precaution; human reports of serious harm are lacking, so it is best treated as a reason for caution rather than alarm.
alprazolam + kava
Kava's active compounds (kavalactones) act on the brain's GABA-A receptor, the same inhibitory system that alprazolam, a benzodiazepine, enhances. Taken together they cause additive central nervous system depression. A published case report describes a previously healthy 54-year-old man who became semi-comatose after three days of combining kava with his prescribed alprazolam, recovering once the kava was stopped. Kava also carries an independently documented risk of liver injury.
zolpidem + valerian
Zolpidem is a Z-drug hypnotic that acts on the GABA-A receptor, and valerian's valerenic acid also has GABA-related sedative activity. In theory the two could add to each other's drowsiness, so it is sensible not to layer them. The best available review of valerian, however, found no evidence of clinically relevant interactions, and there is no human study of this specific combination.
alcohol + kava
Kava and alcohol both depress the central nervous system, producing additive sedation and impaired coordination. More importantly, both are hepatotoxic: kava is a well-documented cause of severe and occasionally fatal liver injury, and alcohol adds a second liver stressor.
diphenhydramine + valerian
Diphenhydramine (a sedating antihistamine) and valerian root both depress the central nervous system, through histaminergic and GABAergic pathways respectively. Taken together their sedative effects add up, increasing drowsiness, next-day impairment, and fall risk.
alcohol + zolpidem
Zolpidem (Ambien) and alcohol both increase activity at the GABA-A receptor, producing additive sedation, impaired psychomotor performance, and an elevated risk of complex sleep behaviors, falls, and — at higher levels of intoxication — respiratory depression. The combination is an additive pharmacodynamic effect; the FDA interaction study found no change in zolpidem blood levels from alcohol.
alcohol + alprazolam
Alcohol and alprazolam (Xanax) both depress the central nervous system by enhancing GABA-A receptor activity. Taken together they produce additive — and sometimes synergistic — sedation, slowed breathing, and impaired coordination, which substantially raises the risk of overdose and death even when neither is taken in a large amount.
alcohol + diazepam
Diazepam (Valium) and alcohol are both central nervous system depressants that act on the GABA-A receptor, producing additive and sometimes greater-than-additive sedation with a real risk of dangerously slowed breathing, loss of consciousness, and death. Diazepam and its active breakdown products linger in the body for days, so the dangerous window extends well beyond a single dose.
alcohol + trazodone
Trazodone and alcohol both depress the central nervous system, producing additive sedation, dizziness, orthostatic hypotension, and impaired coordination. The FDA label states trazodone may enhance the response to alcohol, and combining the two raises the risk of falls and accidents. Rarely, trazodone is associated with QT prolongation, orthostatic syncope, and priapism.
alcohol + mirtazapine
Mirtazapine and alcohol both depress the central nervous system, producing additive sedation, drowsiness, and impaired coordination and judgment. Mirtazapine's strong H1-antihistamine activity makes the sedative interaction with alcohol particularly pronounced, and the FDA label specifically advises avoiding alcohol during treatment.
valerian tea + benzodiazepines
Valerian (Valeriana officinalis) appears to act on the same GABA-A receptor system as benzodiazepines, so taking the two together may add to the sedative effect. The human evidence is largely theoretical and case-level, but the plausible result is extra drowsiness, slower reaction time, and more next-day grogginess.
alcohol + valerian
Valerian and alcohol both act on the GABA-A receptor system and are central nervous system depressants. Combining them carries a recognized possibility of additive sedation — more drowsiness, slower reactions, and impaired coordination than either alone. Most of this rests on shared mechanism and expert caution rather than large human outcome trials, but the practical concern is real: impaired driving and falls, particularly in older adults.
diphenhydramine + melatonin
Diphenhydramine and melatonin both promote sleepiness through different mechanisms (H1 antihistamine blockade and MT1/MT2 receptor activation). Used together they have an additive sedating effect, which can mean heavier-than-expected drowsiness, lingering next-day grogginess, slower reaction time, and a higher fall risk, especially in older adults.
thc + benzodiazepines
THC (the main psychoactive compound in cannabis) and benzodiazepines both depress the central nervous system, so combining them adds up to stronger sedation, impaired coordination, memory problems, and slowed breathing. Cannabinoids, especially CBD, can also inhibit the liver enzyme CYP3A4 that clears several benzodiazepines, raising and prolonging their levels.