Sphingosine 1-Phosphate (S1P) Receptor Modulator. Indications: Multiple sclerosis: Treatment of relapsing forms of multiple sclerosis (MS) to reduce the frequency of clinical exacerbations and to delay the accumulation of physical disability.

Cautions: susceptibility to QT-interval prolongation (including electrolyte disturbances, concomitant use of drugs that prolong QT interval).

severe respiratory disease pulmonary fibrosis.

chronic obstructive pulmonary disease.

risk of macular oedema—eye examination recommended

3–4 months after initiation of treatment (and before initiation of treatment in patients with diabetes or history of uveitis)

monitor hepatic transaminases before treatment, then every 3 months for 1 year, then periodically thereafter. monitor full blood count before treatment, at 3 months, then at least yearly thereafter and if signs of infection— interrupt treatment if lymphocyte count reduced—. monitor for signs and symptoms of haemophagocytic syndrome (including pyrexia, asthenia, hepato- splenomegaly and adenopathy—may be associated with hepatic failure and respiratory distress also progressive cytopenia, elevated serum-ferritin concentrations, hypertriglyceridaemia, hypofibrinogenaemia, coagulopathy, hepatic cytolysis, hyponatraemia)—initiate treatment immediately; check varicella zoster virus status— for further information.

Contra-indications: immunosuppression; active infection; active malignancies (except cutaneous basal cell carcinoma). Hepatic impairment: use with caution in mild to moderate impairment and avoid in severe impairment.

Pregnancy: avoid (toxicity in animal studies): exclude pregnancy: before treatment and ensure effective contraception during and for at least 2 months after treatment.

Breast-feeding: avoid

Side Effects: Most common: Central nervous system: Headache. Gastrointestinal: Diarrhea. Hepatic: Increased ALT, increased AST. Neuromuscular & skeletal: Back pain Miscellaneous: Flu-like syndrome. Less common: Cardiovascular: Hypertension, bradycardia. Central nervous system: Depression, dizziness, migraine.

Dermatologic: Alopecia, eczema, pruritus. Endocrine & metabolic: Increased triglycerides. Gastrointestinal: Gastroenteritis, weight loss. Hematologic: Lymphopenia, leukopenia. Hepatic: Increased GGT. Neuromuscular & skeletal: Paresthesia, weakness. Ocular: Blurred vision, eye pain. Respiratory: Cough, bronchitis, dyspnea, sinusitis. Miscellaneous: Herpes infection, tinea infection.

Rare: (Limited to important or life-threatening): Asystole, AV block, death, lymphoma, macular edema (incidence increased in patients with uveitis or diabetes mellitus), QT prolongation, syncope.

Dose: ADULT over 18 years: 500 micrograms once daily.