Dosing and uses of Targretin (bexarotene)
Adult dosage forms and strengths
capsule
- 75mg
geL
- 1%
Cutaneous T-Cell Lymphoma
300 mg/sq.meter PO qDay with food; titrate based on response or toxicity
Topical: initial apply to lesions qOD x 1 week, THEN increase qWeek up to QId
Monitor: WBC, LFTs, lipids, thyroid function
Pediatric dosage forms and strengths
Safety & efficacy not established
Targretin (bexarotene) adverse (side) effects
>10%
Oral (CTCL trial)
- Peripheral edema (11-13%)
- Headache (30-42%), fever (5-17%), chills (10-13%), insomnia (5-11%)
- Exfoliative dermatitis (10-28%), rash (16-23%), alopecia (4-12%), dry skin (10-11%)
- Diarrhea (7-41%), nausea (8-16%), vomiting (4-13%), abdominal pain (4-11%)
- Bacterial infection (1-13%), flu syndrome (4-13%), infections (13-23%)
- Leukopenia (17-47%), anemia (6-25%), lactic dehydrogenase increased (7-13%), hypochromic anemia (4-13%)
- Hyperlipidemia (78-79%), hypercholesteremia (32-62%), hypothyroidism (29-52%)
- Back pain (2-11%)
TopicaL
- Rash (72%)
- Pruritus (36%)
- Pain (30%)
- Infection (18%)
- Contact dermatitis (14%)
- Headache (14%)
1-10%
OraL
- Hemorrhage, hypertension
- Hypothyroidism
- Pharyngitis, rhinitis
- Arthralgia
- Blephartis, corneal lesion
- Renal dysfunction
TopicaL
- Edema (10%)
- Hyperlipemia (10%)
- Asthenia (6%)
- Exfoliative dermatitis (6%)
- Leukopenia (6%), lymphadenopathy (6%), WBC changes (6%)
- Cough increased (6%), pharyngitis (6%)
- Sweating (6%)
Warnings
Black box warnings
Bexarotene is a retinoid
Retinoids are associated with birth control defects in humans and are contraindicated during pregnancy
Effective contraception must be in place 1 month before initiation of therapy, during therapy, and for at least 1 month after discontinuation of therapy
Contraindications
Hypersensitivity to retinoids
Pregnancy (use 2 forms of contraception)
Cautions
Do not use occlusive dressings w/ geL
Pregnancy and lactation
Pregnancy category: X
Lactation: It is not known whether bexarotene is excreted in human milk. Because of the potential for serious adverse reactions in nursing infants from bexarotene, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Targretin (bexarotene)
Half-Life: 7 hr
Peak Plasma Time: 2 hr
Protein Bound: >99%
Metabolism: by CYP3A4
Metabolites: 6- & 7- hydroxy- bexarotene, 6- & 7- oxo- bexarotene
Excretion: bile
Mechanism of action
Retinoid X receptor activator, regulates genes that control cell differentiation
