Drilldown: Medicines

Cetirizine (1) · Loratadine (1) · Montelukast (1) · Valacyclovir (1)

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

[[:Category:Anti-herpesvirus_agents|Anti-herpesvirus agent]] (1) · [[:Category:Antiasthmatic_agents|Antiasthmatic]] (1) · [[:Category:Antihistamines|Antihistamine]] (2) · [[:Category:Antivirals|Antiviral]] (1) · [[:Category:H1_receptor_antagonists|Histamine H1 receptor antagonist (second-generation)]] (2) · [[:Category:Leukotriene_receptor_antagonists|Leukotriene receptor antagonist]] (1) · [[:Category:Nucleoside_analogs|Nucleoside analog (prodrug)]] (1)

None (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-000005D0-QINU`"' Selectivity comes from the viral-kinase-only initial phosphorylation step, which is why uninfected cells generate minimal active drug'"`UNIQ--ref-000005D1-QINU`"'. Dose-adjust by renal function; rare crystalline nephropathy with rapid IV acyclovir. (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)

'"`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-000005D2-QINU`"', '"`UNIQ--vote-000005D3-QINU`"', '"`UNIQ--vote-000005D4-QINU`"', '"`UNIQ--vote-000005D5-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) · Initial genital herpes 1 g PO BID × 10 days; recurrent 500 mg BID × 3 days; suppression 500 mg-1 g PO daily; zoster 1 g TID × 7 days (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) · 5 mg, 10 mg tablets; 5 mg, 10 mg chewables; 1 mg/mL oral syrup; OTC (1) · 500 mg, 1 g tablets (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) · Bronchodilation within 1-2 hours; full controller effect 1-2 weeks (1) · Symptom relief within 24-48 hours (1)

24 hours (3) · 8 hours per dose (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) · ~3 hours (acyclovir, the active metabolite); longer in renal impairment'"`UNIQ--ref-000005D6-QINU`"' (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) · ~55% bioavailability of acyclovir after valacyclovir oral (vs ~20% from oral acyclovir directly)'"`UNIQ--ref-000005D7-QINU`"' (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) · Widely used in pregnancy when antiviral indicated; reassuring registry data.<sup class="pcp-cn" title="This claim needs a citation.">&#91;[[Pharmacopedia:Citation needed|citation&nbsp;needed]]&#93;</sup> (1)

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