Abbreviated Prescribing Information: Zonisamide 20mg/ml Oral Suspension
Consult Summary of Product Characteristics before prescribing. Presentation: White to off-white oral suspension with each 1 ml of suspension containing 20 mg of Zonisamide. Therapeutic Indications: Zonisamide oral suspension is indicated for use as monotherapy in the treatment of partial seizures, with or without secondary generalization, specifically in adults with newly diagnosed epilepsy. Furthermore, the formulation is indicated as adjunctive therapy for the treatment of partial seizures, with or without secondary generalization, in adults, adolescents, and children aged 6 years and above. Posology: Zonisamide oral suspension can be taken with or without food. For adult monotherapy, the usual maintenance dose is 300 mg (15 ml) once daily, which may be increased in 100 mg (5 ml) increments at two-week intervals up to a maximum of 500 mg (25 ml) per day. For adjunctive therapy, the maintenance range is 300 mg to 500 mg (15 to 25 ml) per day, given either once daily or in two divided doses. For adjunctive therapy, the titration should occur at one-week intervals in increments of 100 mg (5 ml). Paediatric population: In paediatric patients aged ≥6 years, zonisamide must be used as adjunctive therapy. For those weighing 20–55 kg, the recommended maintenance dose is 6–8 mg/kg/day. Dose titration should be in 1 mg/kg (0.05 mL/kg) increments: at weekly intervals when co-administered with CYP3A4-inducing agents, and at two-week intervals in their absence. For patients weighing >55 kg, the usual maintenance dose is 300–500 mg/day (15–25 mL/day). Method of Administration: For oral administration. Contra-indications: Zonisamide oral suspension is contraindicated in patients with hypersensitivity to zonisamide or to any of the excipients. Special Warnings and Precautions for use: Zonisamide should be initiated cautiously in elderly patients and in those with renal or mild-to-moderate hepatic impairment, with slower titration where appropriate; it is not recommended in severe hepatic impairment. Treatment must be discontinued immediately in cases of acute renal failure or sustained, clinically significant increases in serum creatinine, and withdrawn gradually in all patients to minimise the risk of seizure exacerbation. Zonisamide should be discontinued if an unexplained rash occurs; serious skin reactions, including Stevens–Johnson syndrome, have been reported. As a sulphonamide derivative, it may cause rare but potentially fatal immune-mediated reactions, including severe hypersensitivity and haematological disorders such as aplastic anaemia. Acute myopia with secondary angle-closure glaucoma has been reported and requires prompt discontinuation and management. Patients should be monitored for suicidal ideation and behaviour. Nephrolithiasis and metabolic acidosis (more frequent and severe in paediatric patients) may occur; serum bicarbonate should be monitored, and dose reduction or discontinuation considered as appropriate. Hyperammonaemia, with or without encephalopathy, has also been reported. Concomitant use with carbonic anhydrase inhibitors should be avoided in paediatric patients and used with caution in adults, and caution is advised with medicines predisposing to heat-related disorders, particularly in children due to risk of decreased sweating and hyperthermia. Monitor pancreatic enzymes and creatine phosphokinase if pancreatitis or rhabdomyolysis is suspected and discontinue if confirmed. Women of childbearing potential must use effective contraception during treatment and for one month after discontinuation; use is contraindicated in those not using effective contraception. Zonisamide may cause clinically significant weight loss; consider discontinuation if substantial weight loss occurs. Use caution in paediatric patients under 6 years of age or weighing less than 20 kg, and it is not recommended in underweight children or those with decreased appetite. Elevated liver enzymes and bilirubin have been reported in paediatric patients; liver function should be evaluated if dysfunction is suspected and discontinuation considered. A higher incidence of cognitive adverse effects has been observed in paediatric trials compared with placebo. Any warning from the MC, CHM CSM or MHRA: No. Black Triangle notice: not applicable. Very common, common and serious adverse reactions: very common: Agitation, anorexia, ataxia, confusional state, decreased bicarbonate, depression, diplopia, dizziness, irritability, memory Impairment, and somnolence. Common: Abdominal pain, affect lability, alanine aminotransferase increased, alopecia, anxiety, aspartate aminotransferase increased, blood creatinine phosphokinase increased, bradyphrenia, constipation, decreased appetite, diarrhoea, disturbance in attention, dyspepsia, ecchymosis, fatigue, hypersensitivity, influenza-like illness, insomnia, mood swings, nausea, nephrolithiasis, nystagmus, oedema peripheral, paraesthesia, pruritus, psychotic disorder, pyrexia, rash, speech disorder, tremor, vomiting and weight decreased. Serious: Agranulocytosis, amnesia, angle closure glaucoma, aplastic anaemia, blood creatinine increased, blood urea increased, cholecystitis, Cholelithiasis, coma, drug rash with eosinophilia and systemic symptoms, drug-induced hypersensitivity syndrome, erythema multiforme, grand mal seizure, hallucination, heat stroke, hepatocellular damage, hydronephrosis, hypersensitivity-type pneumonitis, leukopenia, leucocytosis, lymphadenopathy, major haematological disturbances, metabolic acidosis, myasthenic syndrome, neuroleptic malignant syndrome, pancreatitis, pancytopenia, pneumonia, renal failure, renal tubular acidosis, respiratory disorder, rhabdomyolysis, status epilepticus, Stevens-Johnson syndrome, thrombocytopenia and toxic epidermal necrolysis. Refer to the SmPC for full details of adverse reactions. Legal Category: Prescription only medicine. Pack Size and NHS Price: 150 ml- £109.14.
Marketing Authorisation Number: PL 00427/0257. Marketing Authorisation Holder: Rosemont Pharmaceuticals Ltd, Rosemont House, Yorkdale Industrial Park, Braithwaite Street, Leeds, LS11 9XE, UK. Date of Preparation: [February-2026]