Drilldown: Medicines

None (1) · Cetirizine (1) · Levothyroxine (1) · Loratadine (1) · Montelukast (1) · Thyroid (desiccated) (1)

Armour Thyroid, NP Thyroid, Nature-Throid, WP Thyroid (1) · Claritin, Alavert, Tavist ND (1) · Rexulti (1) · Singulair (1) · Synthroid, Levoxyl, Tirosint, Unithroid, Euthyrox (1) · Zyrtec, Zyrtec-D (1)

5HT1A activity than aripiprazole (1) · 5HT2A (1) · Atypical antipsychotic (1) · D2/5HT1A partial agonist with stronger α1A (1) · [[:Category:Antiasthmatic_agents|Antiasthmatic]] (1) · [[:Category:Antihistamines|Antihistamine]] (2) · [[:Category:H1_receptor_antagonists|Histamine H1 receptor antagonist (second-generation)]] (2) · [[:Category:Hormone_replacement|Hormone replacement]] (2) · [[:Category:Leukotriene_receptor_antagonists|Leukotriene receptor antagonist]] (1) · [[:Category:Thyroid_hormones|Thyroid hormone]] (2)

None (1) · Partial agonist at D2 and 5HT1A. Antagonist at 5HT2A, α1A, α1B, α2C. More potent 5HT2A antagonism, 5HT1A partial agonism, and α1 antagonism (relative to D2 partial agonism) than aripiprazole, proposed to reduce akathisia and enhance affective/cognitive effects. (1) · Synthetic T4 (thyroxine); peripherally deiodinated to T3 (triiodothyronine), the active hormone. '"`UNIQ--vote-00000031-QINU`"' Narrow therapeutic index; brand-to-generic switches can shift TSH and require re-titration'"`UNIQ--ref-00000032-QINU`"'. (1) · '"`UNIQ--vote-00000016-QINU`"' Brand-to-brand and lot-to-lot variability in T3:T4 ratio is greater than with synthetic levothyroxine, which is why endocrine guidelines prefer the synthetic'"`UNIQ--ref-00000017-QINU`"'. (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)

Schizophrenia (FDA-approved 2015). Adjunctive treatment of major depressive disorder (2015). '''Agitation associated with dementia due to Alzheimer disease''' (FDA-approved May 2023, first agent specifically approved for this problem). Investigational for PTSD (combined with sertraline). (1) · '"`UNIQ--vote-00000018-QINU`"', '"`UNIQ--vote-00000019-QINU`"' (1) · '"`UNIQ--vote-00000033-QINU`"', '"`UNIQ--vote-00000034-QINU`"', '"`UNIQ--vote-00000035-QINU`"' (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)

1.6 mcg/kg/d in young healthy adults; 25-50 mcg/d in elderly or cardiac disease, titrated by TSH at 6-8 weeks (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) · 30 mg PO daily (1/2 grain); titrate by TSH at 6-8 weeks; 60 mg desiccated thyroid is approximately equivalent to 88-100 mcg levothyroxine (1) · Schizophrenia: 1 mg PO daily × 4 days, then 2 mg daily × 3 days, then 4 mg daily. MDD adjunct: 0.5-1 mg daily, increase to 2 mg max. AD agitation: 0.5 mg daily, titrate to 2-3 mg daily. (1)

0.25 mg, 0.5 mg, 1 mg, 2 mg, 3 mg, 4 mg tablets (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) · 15, 30, 60, 90, 120, 180, 240, 300 mg tablets (1/4 to 5 grains; 1 grain = 60 mg) (1) · 25, 50, 75, 88, 100, 112, 125, 137, 150, 175, 200, 300 mcg tablets; oral capsule and IV/IM also available (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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IV (1) · Oral (6)

1-3 hours (slower onset than cetirizine; symptom relief somewhat less) (1) · 30-60 minutes (1) · Bronchodilation within 1-2 hours; full controller effect 1-2 weeks (1) · TSH normalization 4-8 weeks (1) · TSH normalization 4-8 weeks; symptomatic improvement weeks to months (1) · Weeks for psychosis/depression; AD agitation benefit emerges over weeks (1)

24 hours (3) · Daily dosing (1) · Steady-state at 4-6 weeks (2)

2.7-5.5 hours'"`UNIQ--ref-0000015E-QINU`"' (1) · 8-10 hours (longer in elderly and renal impairment)'"`UNIQ--ref-00000396-QINU`"' (1) · T4 ~7 days; T3 ~1 day'"`UNIQ--ref-0000001A-QINU`"' (1) · ~7 days (euthyroid); longer in hypothyroidism (~9-10 days), shorter in hyperthyroidism'"`UNIQ--ref-00000036-QINU`"' (1) · ~8 hours (parent); ~28 hours (desloratadine, the active metabolite, marketed separately as Clarinex)'"`UNIQ--ref-00000621-QINU`"' (1) · ~91 hours (1)

40-80% (oral); reduced by food, calcium, iron, PPIs, fiber; take fasting with water'"`UNIQ--ref-00000037-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) · Variable; reduced by food, calcium, iron, PPIs'"`UNIQ--ref-0000001B-QINU`"' (1) · ~64% (oral; not significantly affected by food)'"`UNIQ--ref-0000015F-QINU`"' (1) · ~95% (1)

First-line in pregnancy; dose typically increased 25-30% due to estrogen-driven rise in TBG and fetal demand. Lactation safe at physiologic doses.<sup class="pcp-cn" title="This claim needs a citation.">&#91;[[Pharmacopedia:Citation needed|citation&nbsp;needed]]&#93;</sup> (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; National Pregnancy Registry available (1) · Synthetic levothyroxine is the standard-of-care in pregnancy; desiccated thyroid use in pregnancy is not well studied.'"`UNIQ--ref-0000001C-QINU`"' (1)

OTC in US (2) · Rx (1) · [[USLegal:Prescription only|Rx-only]] in US (2) · [[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)