Drilldown: Medicines

None (1) · Cetirizine (1) · Loratadine (1) · Montelukast (1)

Claritin, Alavert, Tavist ND (1) · Nuplazid (1) · Singulair (1) · Zyrtec, Zyrtec-D (1)

Selective 5HT2A inverse agonist (with weaker 5HT2C inverse agonism) (1) · [[:Category:Antiasthmatic_agents|Antiasthmatic]] (1) · [[:Category:Antihistamines|Antihistamine]] (2) · [[:Category:H1_receptor_antagonists|Histamine H1 receptor antagonist (second-generation)]] (2) · [[:Category:Leukotriene_receptor_antagonists|Leukotriene receptor antagonist]] (1)

None (1) · Selective inverse agonist at 5HT2A receptors with weaker activity at 5HT2C. Has no significant dopamine D2 affinity, unique among approved antipsychotics. Inverse agonism (rather than antagonism) reduces constitutive 5HT2A receptor activity below baseline. (1) · '"`UNIQ--vote-00000391-QINU`"' Minimal CYP metabolism; mostly renally cleared unchanged. Cetirizine is the active racemate; levocetirizine is the active R-enantiomer marketed separately'"`UNIQ--ref-00000392-QINU`"'. (1) · '"`UNIQ--vote-0000061E-QINU`"' Less reliably anticholinergic than first-generation H1s; minimal antiemetic effect. Desloratadine (Clarinex) is the active enantiomer-of-metabolite version marketed as a Rx alternative. (1)

Hallucinations and delusions associated with Parkinson's disease psychosis (PDP). Investigational for psychosis in other dementias and as augmentation for depression. (1) · '"`UNIQ--vote-0000015B-QINU`"', '"`UNIQ--vote-0000015C-QINU`"', '"`UNIQ--vote-0000015D-QINU`"' (1) · '"`UNIQ--vote-00000393-QINU`"', '"`UNIQ--vote-00000394-QINU`"', '"`UNIQ--vote-00000395-QINU`"' (1) · '"`UNIQ--vote-0000061F-QINU`"', '"`UNIQ--vote-00000620-QINU`"' (1)

10 mg PO once daily (1) · 10 mg PO once daily (5 mg in older adults or if sedation occurs) (1) · 10 mg PO once daily in the evening (adults); 4-5 mg in children (1) · 34 mg PO once daily (1)

10 mg tablets; 4 mg, 5 mg chewables; 4 mg granules (1) · 10 mg tablets; 5 mg ODT and chewables; 1 mg/mL oral syrup; combo Claritin-D (with pseudoephedrine, behind-counter) (1) · 10 mg, 34 mg capsules/tablets (1) · 5 mg, 10 mg tablets; 5 mg, 10 mg chewables; 1 mg/mL oral syrup; OTC (1)

None · Indication-specific · 40 mg/d · 10 mg/d · 20 mg/d · 80 mg/d · 10 mg/d (adults) · 100 mg/d · 4 g/d · 400 mg/d · 40 mg/d typical; up to 240 mg/d for Zollinger-Ellison · 5 mg/d · 50 mg/d · 600 mg/d · No fixed ceiling; titrate to clinical effect and tolerability with CDC opioid prescribing guidance constraints on morphine-milligram-equivalent (MME) totals · No fixed maximum; titrated to TSH target · TID per eye · Titrated to glucose; no fixed ceiling · Titrated to glucose; no fixed maximum · '''20 mg/day in adults >60 years''' per FDA's 2011-2012 QT-prolongation warning; 40 mg/day in adults ≤60

Other values:

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Oral (4)

1-3 hours (slower onset than cetirizine; symptom relief somewhat less) (1) · 30-60 minutes (1) · Benefit over weeks of dosing (1) · Bronchodilation within 1-2 hours; full controller effect 1-2 weeks (1)

24 hours (3) · Daily dosing (1)

2.7-5.5 hours'"`UNIQ--ref-0000015E-QINU`"' (1) · 8-10 hours (longer in elderly and renal impairment)'"`UNIQ--ref-00000396-QINU`"' (1) · ~57 hours (parent), ~200 h (active metabolite) (1) · ~8 hours (parent); ~28 hours (desloratadine, the active metabolite, marketed separately as Clarinex)'"`UNIQ--ref-00000621-QINU`"' (1)

High (oral); not significantly affected by food'"`UNIQ--ref-00000397-QINU`"' (1) · High (oral; food prolongs absorption modestly)'"`UNIQ--ref-00000622-QINU`"' (1) · Not characterized; oral dosing once daily (1) · ~64% (oral; not significantly affected by food)'"`UNIQ--ref-0000015F-QINU`"' (1)

Generally considered safe; pregnancy registries do not show increased major malformation risk.<sup class="pcp-cn" title="This claim needs a citation.">&#91;[[Pharmacopedia:Citation needed|citation&nbsp;needed]]&#93;</sup> (1) · Generally considered safe; widely used. Levocetirizine (the R-enantiomer) is an alternative with similar safety.<sup class="pcp-cn" title="This claim needs a citation.">&#91;[[Pharmacopedia:Citation needed|citation&nbsp;needed]]&#93;</sup> (1) · Generally considered safe; widely used. Loratadine and cetirizine are the most-recommended 2nd-gen H1s in pregnancy and lactation.<sup class="pcp-cn" title="This claim needs a citation.">&#91;[[Pharmacopedia:Citation needed|citation&nbsp;needed]]&#93;</sup> (1) · Limited data; avoid (1)

OTC in US (2) · Rx. FDA black-box warning for increased mortality in elderly patients with dementia-related psychosis (class warning shared with all antipsychotics) (1) · [[USLegal:Prescription only|Rx-only]] in US. '''FDA Boxed Warning (2020):''' neuropsychiatric events including agitation, depression, sleep disturbance, and suicidal thoughts; benefit-risk should be reassessed regularly'"`UNIQ--ref-00000160-QINU`"'. (1)