Gliolan

Gliolan is a prescription‑only diagnostic agent that contains the active ingredient aminolevulinic acid hydrochloride. It is supplied as an oral formulation, though specific strength and dosage form are not detailed. Classified as a photosensitizer prodrug, Gliolan is used in the European market to aid intra‑operative visualization of malignant brain tumors through fluorescence guidance after oral administration before surgery and to support surgical decision‑making in the operating room.

Gliolan is indicated for fluorescence‑guided resection of malignant gliomas and other brain tumors during neurosurgical procedures.

- Oral administration of Gliolan prior to craniotomy to enable tumor fluorescence under blue light. - Use in conjunction with a surgical microscope equipped with a fluorescence filter to differentiate tumor tissue from normal brain. - Application in intra‑operative mapping to assist surgeons in achieving maximal safe resection while preserving functional areas. - Integration into multimodal imaging protocols, complementing MRI or PET data for surgical planning. - Potential use in research settings to evaluate fluorescence‑guided techniques for other solid tumors.

The safety profile of Gliolan reflects the pharmacologic activity of its metabolite, protoporphyrin IX, and the procedure‑related context of its use.

Common: - Transient skin photosensitivity, manifesting as mild redness or itching when exposed to bright light. - Nausea or mild gastrointestinal discomfort following oral intake. - Headache or dizziness during the peri‑operative period. - Temporary visual disturbances, such as altered color perception under the fluorescence filter. - Mild fatigue or somnolence reported in the hours after administration.

Serious: - Severe photosensitivity reactions, including blistering or burns on exposed skin. - Allergic reactions ranging from urticaria to anaphylaxis, though rare. - Elevated liver enzymes indicating hepatic stress in susceptible patients. - Seizure activity potentially precipitated by fluorescence illumination in patients with pre‑existing epilepsy.

When using Gliolan, clinicians should observe specific precautions to minimize risks associated with photosensitivity and the intra‑operative environment.

- Administer the drug in a dimly lit environment and advise patients to avoid direct sunlight for 24 hours after dosing. - Confirm the availability of a fluorescence‑compatible surgical microscope before the procedure. - Assess liver function prior to administration, as hepatic impairment may affect metabolite accumulation. - Screen for a history of photosensitivity disorders or porphyria before prescribing. - Monitor patients for allergic reactions during and after infusion, with emergency equipment on hand. - Document the timing of oral dose relative to surgical start to ensure optimal fluorescence intensity.

Gliolan may interact with agents that influence photosensitivity, hepatic metabolism, or the optical environment of the operating room.

Avoid: - Avoid concurrent use of strong photosensitizing drugs such as tetracyclines, sulfonamides, or psoralen derivatives. - Do not combine with other fluorescent dyes that emit at similar wavelengths, as this can obscure tumor visualization.

Use with caution: - Use caution when administering drugs metabolized by the hepatic cytochrome P450 system, including certain anticonvulsants. - Caution is advised with agents that may lower seizure threshold, especially in patients with epilepsy. - Exercise care when using anesthetic agents that affect cerebral blood flow, as this may alter fluorescence intensity. - Monitor for potential additive effects with other agents that cause skin photosensitivity, such as retinoids.