SOLARAZE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SOLARAZE (SOLARAZE).
Solaraze (diclofenac sodium) is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2) enzymes, reducing prostaglandin synthesis, which mediates inflammation and pain. In actinic keratosis, it may also induce apoptosis and decrease keratinocyte proliferation.
| Metabolism | Diclofenac undergoes hepatic metabolism primarily via CYP2C9, with minor contributions from CYP3A4. Major metabolites include 4'-hydroxydiclofenac and 5-hydroxydiclofenac, which are excreted in urine and bile as glucuronide and sulfate conjugates. |
| Excretion | Solaraze (diclofenac sodium 3% gel) is primarily eliminated via hepatic metabolism followed by renal excretion of metabolites. Approximately 65% of a dose is excreted in urine as conjugated metabolites, with less than 1% as unchanged drug. About 35% is eliminated in feces via biliary excretion of metabolites. |
| Half-life | Following topical application, the terminal elimination half-life of diclofenac from plasma is approximately 12 hours (range 8-15 hours). This reflects the slow absorption and distribution from the skin depot, with clinical relevance for twice-daily dosing. |
| Protein binding | Diclofenac is highly protein-bound (99.7%), primarily to serum albumin. |
| Volume of Distribution | Volume of distribution (Vd) after topical application: Apparent Vd is approximately 0.17 L/kg (range 0.1-0.2 L/kg). The small Vd reflects extensive plasma protein binding and limited tissue distribution. Clinical meaning: Diclofenac is confined primarily to the vascular compartment and well-perfused organs, with minimal deep-tissue penetration. |
| Bioavailability | Systemic bioavailability of diclofenac from Solaraze gel is approximately 10% (range 5-15%) compared to oral diclofenac, due to limited percutaneous absorption. After repeated application, steady-state plasma concentrations are about 1/20th of those achieved with oral dosing. |
| Onset of Action | Onset of action for actinic keratosis clearance: Clinical improvement may be noted after 4-8 weeks of twice-daily application. Complete clearance typically requires 60-90 days of continuous therapy. |
| Duration of Action | Duration of action: The pharmacodynamic effect on lesion clearance persists after treatment cessation, with sustained clearance for several months. However, drug levels decline with a half-life of 12 hours, requiring twice-daily application to maintain therapeutic skin concentrations. |
Apply 0.5 mL (1 unit dose) topically to actinic keratoses twice daily for 2 to 4 weeks, then 1 week off, repeat for a total of 3 treatment cycles.
| Dosage form | GEL |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | No dose adjustment required for hepatic impairment. |
| Pediatric use | Safety and efficacy in pediatric patients have not been established; not recommended for use in children. |
| Geriatric use | No specific dose adjustment; skin sensitivity may increase with age; monitor for local adverse reactions. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SOLARAZE (SOLARAZE).
| Breastfeeding | Topical diclofenac has negligible systemic absorption (plasma levels <5 ng/mL), resulting in low transfer into breast milk. The M/P ratio is not established for topical use, but based on oral diclofenac (M/P ~0.3), infant dose via milk is <0.1% of maternal weight-adjusted dose. Use is generally considered compatible with breastfeeding, but avoid application to breast area to prevent direct infant exposure. |
| Teratogenic Risk | SOLARAZE (diclofenac sodium 3% gel) is a topical NSAID. Systemic absorption is minimal (approximately 1-2% of applied dose), but NSAIDs are associated with fetal risks. First trimester: Risk of spontaneous abortion and congenital malformations (cardiac defects, gastroschisis) from systemic NSAIDs; however, topical exposure is considered low risk. Second trimester: No documented specific adverse effects with topical use; risk of oligohydramnios from systemic NSAIDs is theoretical but unlikely due to low absorption. Third trimester: Systemic NSAIDs cause premature closure of ductus arteriosus, oligohydramnios, and fetal renal impairment. Topical use should be avoided due to potential risk of ductal closure, especially after 30 weeks gestation. |
■ FDA Black Box Warning
NSAIDs cause an increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal. This risk may increase with duration of use. Patients with cardiovascular disease or risk factors may be at greater risk. Solaraze is contraindicated in the setting of coronary artery bypass graft (CABG) surgery.
| Serious Effects |
["History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs.","In the setting of CABG surgery.","Known hypersensitivity to diclofenac or any component of the product."]
| Precautions | ["Cardiovascular thrombotic events: Increased risk of MI and stroke.","Gastrointestinal risk: Serious GI adverse events including bleeding, ulceration, and perforation.","Hepatic effects: Elevations in liver enzymes; monitor liver function.","Renal effects: Impaired renal function; use with caution in patients with renal impairment.","Skin reactions: Photosensitivity; avoid sun exposure. Local skin reactions may occur."] |
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| Fetal Monitoring | No specific fetal monitoring is required for topical diclofenac use in pregnancy. However, if used inadvertently in the third trimester, consider prenatal ultrasound to assess amniotic fluid volume and ductus arteriosus patency. |
| Fertility Effects | Topical diclofenac is not expected to impair fertility due to negligible systemic effects. Systemic NSAIDs may cause reversible ovulation suppression, but topical application at recommended doses (3% gel) is unlikely to have a significant impact on fertility. |