Table 10.
Olanzapine Dosage and Monitoring
| Guideline | Dose | Patient monitoring parameters | Specific side effects | Specific drug interactions |
|---|---|---|---|---|
| APA | 25 mg/d fluoxetine plus 6 mg/d olanzapine, 18 mg/d max | General AAP guidance only | General AAP guidance plus long-term weight gain | General AAP guidance only |
| BAP | 2.5–10 mg/d olanzapine | General AAP guidance only | General AAP guidance only | – |
| CANMAT | 2.5–10 mg/d olanzapine | – | – | Moderate potential for drug-drug interactions (1Ae substrate) and is also metabolized through the uridine diphosphate glucuronosyltransferase pathway. Increases serum levels of CYP1A2 CYP substrates and CYP2D6. |
| CPG-S | – | – | Weight gain, dry mouth, appetite increase, fatigue, drowsiness, headache, and edema occurring in ≥10% of patients (Trivedi et al., 2009) | – |
| ICSI | General AAP guidance only | – | – | – |
| MPG | 6.25–12.5 mg/d olanzapine plus 25–50 mg/d fluoxetine | Special precaution to be taken with plasma glucose, which should be checked at baseline, 1 month, and then every 4–6 months | Sedation, anticholinergic, caution advised in hepatic impairment. Reports of transient asymptomatic elevations in ALT and AST in physically healthy adults (Atasoy et al., 2007; Preskorn, 2012; Datapharm Communications Ltd, 2017; Truven Health Analytics, 2018). Very low risk (in relation to other AAPs) of akathisia and parkinsonism. Low relative risk of anticholinergic effects, hypotension, and prolactin elevation. Moderate relative risk of sedation, high relative risk of weight gain. Low relative risk of effects on QTc. Highest propensity for increasing plasma lipids (Chaggar et al., 2011). Prevalence of sexual dysfunction reported to be >50% (Serretti and Chiesa, 2011), priapism reported rarely (Dossenbach et al., 2006). | General AAP guidance/refer to guidelines |
| NICE | – | – | – | – |
| RANZCP | General AAP guidance and lower dose in elderly | General AAP guidance only | General AAP guidance, plus very sedating, increased appetite, metabolic syndrome | – |
| TMAP | 5–10 mg/d, titrated by 5 mg/d to 10–20 mg/d | General AAP guidance only | General AAP guidance, plus constipation, dizziness, dry mouth, glucose dysregulation, hyperlipidaemia, increased appetite, sedation, weight gain | Carbamazepine, fluvoxamine, rifampicin, smoking, St John’s wort |
| WFSBP | General AAP guidance only | – | – | – |
Abbreviations: . ., not reported by guideline; AAPs, atypical antipsychotics; APA, American Psychiatric Association; BAP, British Association of Psychopharmacology; CANMAT, Canadian Network for Mood and Anxiety Disorders; CPG-S, Clinical Practice Guidelines in the Spanish NHS; ICSI, Institute for Clinical Systems Improvement; NICE, National Institute for Health and Care Excellence; MPG, Maudsley Prescribing Guidelines; RANZCP, Royal Australian and New Zealand College of Psychiatrists; TMAP, Texas Medication Algorithm Project; WFSBP, World Federation of Societies of Biological Psychiatry.