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Citalopram (Celexa)

SSRIprescriptionoral · inferred

Racemic SSRI — the S-enantiomer (escitalopram) provides the antidepressant activity while the R-enantiomer is essentially inactive. Clean CYP profile with fewer drug interactions than most SSRIs. FDA-mandated dose ceiling of 40 mg/day (20 mg in elderly/hepatic impairment) due to dose-dependent QTc prolongation. Metabolized by CYP2C19 and CYP3A4 to weakly active demethylcitalopram and didemethylcitalopram.

Projected serum levels — 20 mg, once daily

Citalopram (Celexa)
Citalopram (Celexa) modeled serum levels, 20 mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 4 days. 0 12.5 25 37.5 50 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 4
Citalopram (Celexa) modeled serum levels with a loading dose of 52.8 mg, then 20 mg once daily The first dose is larger so levels approach steady state faster. 0 12.5 25 37.5 50 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule

Maintenance schedule: 20 mg once daily (oral).

Loading schedule: 52.8 mg on day 1, then 20 mg once daily — reaching therapeutic levels sooner.

Modeled steady state after ~4 days: peak ≈ 38.9 mg, trough ≈ 25.9 mg body load. Population-based estimate over 15 days for a 20 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
SSRI
Route modeled
Oral
Model confidence
inferred
Half-life
35 h
Common dose
20 mg
Suggested maximum
40 mg/day
Reference dose range
10–40 mg (single dose)
Suggested cadence
once daily
Validated against
40 mg oral — Cmax 0.063 mg/L at 4 h

Documented interactions

  • danger
    1P-LSD (1-Propionyl-LSD) + Citalopram (Celexa) Serotonin risk

    1P-LSD (1-Propionyl-LSD) and Citalopram (Celexa) both have serotonergic activity. Risk of serotonin syndrome (hyperthermia, rigidity, autonomic instability, altered mental status).

  • danger
    25I-NBOMe + Citalopram (Celexa) Serotonin risk

    25I-NBOMe and Citalopram (Celexa) both have serotonergic activity. Risk of serotonin syndrome (hyperthermia, rigidity, autonomic instability, altered mental status).

  • danger
    2C-I (2,5-Dimethoxy-4-iodophenethylamine) + Citalopram (Celexa) Serotonin risk

    2C-I (2,5-Dimethoxy-4-iodophenethylamine) and Citalopram (Celexa) both have serotonergic activity. Risk of serotonin syndrome (hyperthermia, rigidity, autonomic instability, altered mental status).

  • danger
    2C-B (4-Bromo-2,5-dimethoxyphenethylamine) + Citalopram (Celexa) Serotonin risk

    2C-B (4-Bromo-2,5-dimethoxyphenethylamine) and Citalopram (Celexa) both have serotonergic activity. Risk of serotonin syndrome (hyperthermia, rigidity, autonomic instability, altered mental status).

  • danger
    4-AcO-DMT (Psilacetin) + Citalopram (Celexa) Serotonin risk

    4-AcO-DMT (Psilacetin) and Citalopram (Celexa) both have serotonergic activity. Risk of serotonin syndrome (hyperthermia, rigidity, autonomic instability, altered mental status).

  • danger
    4-MMC (Mephedrone) + Citalopram (Celexa) CYP inhibition

    Citalopram (Celexa) reversible_inhibitor of CYP2D6 predicted to change 4-MMC (Mephedrone) AUC by ~2.27x

Serum checks 289 modeled interaction pairings for citalopram (celexa) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Citalopram versus other antidepressive agents for depression: a Cochrane systematic review Cipriani A et al. · Cochrane Database of Systematic Reviews, 2012 DOI

    Cochrane review of 37 RCTs (6,000+ patients) found citalopram equally effective as other antidepressants for acute depression, with a tolerability profile similar to other SSRIs.

  2. Citalopram for major depressive disorder in adults: a systematic review and network meta-analysis Cipriani A et al. · Lancet, 2018 DOI

    Network meta-analysis of 522 trials found citalopram effective for depression with intermediate efficacy and acceptability among 21 antidepressants studied.

  3. Revised recommendations for citalopram: dose ceiling and QT prolongation risk FDA Drug Safety Communication · FDA Safety Communication, 2012 DOI

    FDA safety communication establishing 40 mg/day maximum dose for citalopram based on thorough QT study showing dose-dependent QTc prolongation of 8.5 ms at 20 mg and 18.5 ms at 60 mg.

3 published studies referenced in the app, each with a plain-language summary.