Mekinist (Trametinib)

Mekinist acts on the MAPK/ERK signaling pathway in tumors with BRAF mutations.

• Metastatic melanoma with BRAF V600E/K mutation: improves progression‑free and overall survival in patients with this genetic profile.
• Non‑small cell lung cancer with BRAF V600E mutation: provides targeted inhibition of tumor growth in this subset of lung cancer.
• Combination therapy with dabrafenib for BRAF‑mutated melanoma: enhances response rates when used together with a BRAF inhibitor.

• Trametinib selectively inhibits the serine‑threonine kinases MEK1 and MEK2, which are key components of the MAPK/ERK pathway. By blocking MEK activity, the drug prevents downstream phosphorylation of ERK, thereby reducing cellular proliferation and survival signals in tumor cells that depend on this pathway for growth.

Common Side Effects

• Rash: mild to moderate skin irritation.
• Diarrhea: watery stools, may lead to dehydration.
• Fatigue: persistent tiredness affecting daily activities.
• Nausea: sensation of needing to vomit.
• Edema: swelling of extremities.
• Acneiform dermatitis: pimples resembling acne.

Serious or Rare Side Effects

• Interstitial lung disease: inflammation of lung tissue requiring immediate medical attention.
• Cardiomyopathy: reduced heart function that may lead to heart failure.
• Retinal disorders: visual disturbances including blurred vision or retinal vein occlusion.
• Severe skin reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Hepatic toxicity: elevated liver enzymes or hepatitis.
• Severe infections: opportunistic infections due to immune modulation.

Before initiating therapy, clinicians should evaluate baseline organ function and monitor throughout treatment.

• Cardiac monitoring: assess ejection fraction prior to and during therapy.
• Liver function tests: check ALT, AST, and bilirubin regularly.
• Ocular assessment: perform baseline eye exam and monitor for visual changes.
• Renal impairment: use with caution in patients with severe renal dysfunction.
• Pregnancy and lactation: safety unknown; avoid unless benefit outweighs risk.
• Store at ambient temperature: keep in original container, protect from moisture and light.

Trametinib may interact with several co‑administered medicines, requiring dose adjustments or monitoring.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampin): may markedly reduce trametinib exposure.
• Strong CYP3A4 inhibitors (e.g., ketoconazole): may increase trametinib plasma levels and toxicity.
• Concurrent use with other MEK inhibitors: additive toxicity risk.

Moderate Interactions (Monitor Closely)

• Anticoagulants (e.g., warfarin): potential increase in bleeding risk.
• QT‑prolonging agents: monitor ECG for arrhythmias.
• Immunosuppressants (e.g., cyclosporine): may alter trametinib metabolism.