Drilldown: Medicines

Fluorouracil (5-FU) (1) · Primidone (1) · Riboflavin (vitamin B2) (1) · Tretinoin (all-trans retinoic acid, ATRA) (1)

Efudex (topical), Carac (topical), Fluoroplex (topical); generic IV (1) · Many generics/OTC (1) · Mysoline (1) · Retin-A, Renova, Atralin, Avita, Tretin-X, Refissa, Altreno; Vesanoid (oral, APL) (1)

APL)]] (1) · [[:Category:Anticonvulsants|Anticonvulsant]] (1) · [[:Category:Antimetabolites|Antimetabolite (pyrimidine analog)]] (1) · [[:Category:Antineoplastics|Antineoplastic (oral (1) · [[:Category:Antineoplastics|Antineoplastic]] (1) · [[:Category:B-vitamins|B-vitamin]] (1) · [[:Category:Barbiturates|Barbiturate (parent compound)]] (1) · [[:Category:Retinoids|Retinoid]] (1) · [[:Category:Topical_retinoids|Topical retinoid]] (1) · [[:Category:Tremor medicines|Tremor medicine]] (1) · [[:Category:Vitamins|Vitamin]] (1)

None (2) · '"`UNIQ--vote-00000013-QINU`"' Strong CYP3A4 induction via the phenobarbital metabolite produces many interactions (reduces oral contraceptives, warfarin, many psychotropics). Essential-tremor efficacy is the unique pharmacological selling point'"`UNIQ--ref-00000014-QINU`"'. (1) · '"`UNIQ--vote-0000124C-QINU`"' The 400 mg/d dose for migraine prophylaxis is supported by randomized trials (Schoenen 1998) and remains a low-risk evidence-based supplement option. Characteristic bright-yellow urine fluorescence with high-dose oral supplementation. (1)

'"`UNIQ--vote-00000015-QINU`"', '"`UNIQ--vote-00000016-QINU`"' (1) · '"`UNIQ--vote-00000BA0-QINU`"', '"`UNIQ--vote-00000BA1-QINU`"', '"`UNIQ--vote-00000BA2-QINU`"' (1) · '"`UNIQ--vote-000011BA-QINU`"', '"`UNIQ--vote-000011BB-QINU`"', '"`UNIQ--vote-000011BC-QINU`"', '"`UNIQ--vote-000011BD-QINU`"' (1) · '"`UNIQ--vote-0000124D-QINU`"', '"`UNIQ--vote-0000124E-QINU`"', '"`UNIQ--vote-0000124F-QINU`"' (1)

Migraine prophylaxis: 400 mg PO daily; deficiency replacement 5-30 mg/d (1) · Seizures: 100-125 mg PO at bedtime x 3 days, then BID, then TID, escalating to 750-1500 mg/day. Essential tremor: 25-50 mg PO at bedtime, titrate slowly to 250-750 mg/day (1) · Topical: 0.5-5% cream/solution to lesions BID × 2-4 weeks; systemic IV: regimen-specific in cancer chemotherapy (1) · Topical: pea-sized amount to dry face at bedtime, building from 2-3×/week to nightly as tolerated; oral APL: 45 mg/m²/d in divided doses (1)

0.5% (Carac), 1% (Fluoroplex), 5% (Efudex) topical creams/solutions; 50 mg/mL IV (1) · 25, 50, 100, 250, 400 mg tablets; OTC (1) · Tablets 50, 250 mg (1) · Topical 0.01-0.1% creams, gels, micropsheres, lotions; oral 10 mg capsules (Vesanoid) (1)

2 g/day (seizures); typically much lower for essential tremor (1) · No strict ceiling for water-soluble vitamin; UL not set (1) · Topical: nightly; oral APL: 45 mg/m²/d (1) · Topical: nightly; systemic: regimen-specific (1)

IV (1) · IV (rare) (1) · Oral (2) · oral (APL only) (1) · Topical (2)

Anticonvulsant effect emerges with slow titration over weeks; tremor effect over weeks (1) · Migraine effect after 1-3 months of daily use (1) · Topical: inflammation, erythema, crusting at 2 weeks; complete response weeks to months after course (1) · Topical: irritation within days; acne improvement 6-12 weeks; oral APL response within days (1)

None · 24 hours · 4-6 hours · 12 hours · 6-8 hours · Daily dosing · 8-12 hours · 12-24 hours · Hours · Hours per application · 24 hours (HS dosing) · 24 hours (once-daily dosing) · 24 h · N/A · N/A (replacement) · Variable · ~7-8 hours · 3-5 hours · 4-6 hours (IR); 24 hours (ER) · 6-12 hours

Other values:

Search

Primidone 5-15 hours; '''phenobarbital active metabolite 50-150 hours'''; PEMA (phenylethylmalonamide) active metabolite 16 hours'"`UNIQ--ref-00000017-QINU`"' (1) · ~0.5-2 hours (oral)'"`UNIQ--ref-00000BA3-QINU`"' (1) · ~1-2 hours plasma (riboflavin itself); FAD/FMN tissue cofactors are continuous (1) · ~10-20 minutes systemically (rapid hepatic and erythrocyte dihydropyrimidine dehydrogenase clearance)'"`UNIQ--ref-000011BE-QINU`"' (1)

Topical: minimal systemic absorption (oral systemic 5-FU not used due to poor and variable absorption)'"`UNIQ--ref-000011BF-QINU`"' (1) · Topical: minimal systemic absorption with normal skin; oral: variable, induced metabolism with repeated dosing'"`UNIQ--ref-00000BA4-QINU`"' (1) · ~50-60% (oral; food enhances) (1) · ~90% (oral)'"`UNIQ--ref-00000018-QINU`"' (1)

None (1) · Safe at replacement and supplement doses.<sup class="pcp-cn" title="This claim needs a citation.">&#91;[[Pharmacopedia:Citation needed|citation&nbsp;needed]]&#93;</sup> (1) · Substantial teratogenic signal (barbiturate class effects including neonatal withdrawal and hemorrhagic disease of newborn).<sup class="pcp-cn" title="This claim needs a citation.">&#91;[[Pharmacopedia:Citation needed|citation&nbsp;needed]]&#93;</sup> (1) · Topical: avoid; systemic: contraindicated in pregnancy.<sup class="pcp-cn" title="This claim needs a citation.">&#91;[[Pharmacopedia:Citation needed|citation&nbsp;needed]]&#93;</sup> (1)

OTC in US (1) · [[USLegal:Prescription only|Rx-only]] in US (2) · [[USLegal:Prescription only|Rx-only]] in US. '''Federally non-controlled despite being a barbiturate''', a paradoxical situation given that its primary active metabolite phenobarbital is Schedule IV'"`UNIQ--ref-00000019-QINU`"' (1)