Treatment with gefitinib should be initiated and supervised by a physician experienced in the use of anticancer therapies.
Posology: The recommended posology of gefitinib is one 250 mg tablet once a day. If a dose is missed, it should be taken as soon as the patient remembers. If it is less than 12 hours to the next dose, the patient should not take the missed dose. Patients should not take a double dose (two doses at the same time) to make up for a forgotten dose.
Paediatric population: The safety and efficacy of gefitinib in children and adolescents aged less than 18 years have not been established. There is no relevant use of gefitinib in the paediatric population in the indication of NSCLC.
Hepatic impairment: Patients with moderate to severe hepatic impairment (Child-Pugh B or C) due to cirrhosis have increased plasma concentrations of gefitinib. These patients should be closely monitored for adverse events. Plasma concentrations were not increased in patients with elevated aspartate transaminase (AST), alkaline phosphatase or bilirubin due to liver metastases (see Pharmacology: Pharmacokinetics under Actions).
Renal impairment: No dose adjustment is required in patients with impaired renal function at creatinine clearance >20 ml/min. Only limited data are available in patients with creatinine clearance ≤20 ml/min and caution is advised in these patients (see Pharmacology: Pharmacokinetics under Actions).
Elderly: No dose adjustment is required on the basis of patient age (see Pharmacology: Pharmacokinetics under Actions).
CYP2D6 poor metabolisers: No specific dose adjustment is recommended in patients with known CYP2D6 poor metaboliser genotype, but these patients should be closely monitored for adverse events (see Pharmacology: Pharmacokinetics under Actions).
Dose adjustment due to toxicity: Patients with poorly tolerated diarrhoea or skin adverse reactions may be successfully managed by providing a brief (up to 14 days) therapy interruption followed by reinstatement of the 250 mg dose (see Adverse Reactions). For patients unable to tolerate treatment after a therapy interruption, gefitinib should be discontinued and an alternative treatment should be considered.
Method of administration: The tablet may be taken orally with or without food, at about the same time each day. The tablet can be swallowed whole with some water or if dosing of whole tablets is not possible, tablets may be administered as a dispersion in water (non-carbonated). No other liquids should be used. Without crushing it, the tablet should be dropped in half a glass of drinking water. The glass should be swirled occasionally, until the tablet is dispersed (this may take up to 20 minutes). The dispersion should be drunk immediately after dispersion is complete (i.e. within 60 minutes). The glass should be rinsed with half a glass of water, which should also be drunk. The dispersion can also be administered through a naso-gastric or gastrostomy tube.