CYP-induction or inhibition are not present in clinical use. Side effects such as nausea, anorexia and vomiting may be potentially porphyrinogenic through reduction in caloric intake.

Lomustine is a nitrosourea-derivative alkylating agent.

Lomustine is an antineoplastic agent used in the treatment of brain tumours and resistant or relapsed Hodgkins disease and other lymphomas. Also used to treat lung cancer, malignant melanoma, and various solid tumours. It is administered orally. Common adverse reactions of lomustine that can be confused with an acute porphyric attack are nausea and vomiting. Side effects such as nausea, anorexia and vomiting may be potentially porphyrinogenic through reduction in caloric intake.

Lomustine is extensively metabolized in the liver partly through CYP3A4-dependent hydroxylations giving rise to alkylation metabolites, and by reductive denitrosation via NADPH-cytochrome P450 reductase. Lomustine is a competative inhibitor of CYP2D6 (Rendic,2002; Le Guellec, 1993) and is listed as an inhibitor of CYP3A4 by Rendic (2002) and Zhou (2007). Lomustine significantly inhibited the biotransformation of vinblastine, a CYP3A4-substrate, in an in-vitro study using human liver microsomes (Zhou-Pan, 1993).Lomustine significantly inhibited vindesine biotransformation (A CYP3A4 substrate) (Zhou, XE, 1993). Human pharmacokinetics not fully elucidated. No interactions with CYP-metabolism of other drugs are reportec that could indicate CYP induction.