Drilldown: Medicines
Use the filters below to narrow your results.
generic:
brand:
classes:
[[: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)
mechanism:
None (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-00000032-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-00000033-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)
uses:
'"`UNIQ--vote-00000033-QINU`"', '"`UNIQ--vote-00000034-QINU`"', '"`UNIQ--vote-00000035-QINU`"' (1) ·
'"`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)
starting dose:
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)
preparations:
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)
fda max: (Click arrow to add another value)
onset:
duration:
halflife:
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-00000036-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)
bioavailability:
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-00000037-QINU`"' (1) ·
~64% (oral; not significantly affected by food)'"`UNIQ--ref-0000015F-QINU`"' (1)
pregnancy:
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.">[[[Pharmacopedia:Citation needed|citation needed]]]</sup> (1) ·
Generally considered safe; pregnancy registries do not show increased major malformation risk.<sup class="pcp-cn" title="This claim needs a citation.">[[[Pharmacopedia:Citation needed|citation needed]]]</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.">[[[Pharmacopedia:Citation needed|citation needed]]]</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.">[[[Pharmacopedia:Citation needed|citation needed]]]</sup> (1) ·
Synthetic levothyroxine is the standard-of-care in pregnancy; desiccated thyroid use in pregnancy is not well studied<sup class="pcp-cn" title="This claim needs a citation.">[[[Pharmacopedia:Citation needed|citation needed]]]</sup> (1)
legal:
OTC in US (2) ·
[[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)
Showing below up to 5 results in range #1 to #5.