ISMO Retard prolonged-release tablet Ref.[49794] Active ingredients: Isosorbide mononitrate

Unless otherwise prescribed one ISMO 40 retard is taken once daily (equivalent to 40 mg isosorbide-5-mononitrate).

For patients with greater nitrate requirements, the dose can be increased to one ISMO 40 retard tablet twice daily (equivalent to 80 mg isosorbide-5-mononitrate).

With a daily regimen of 2 × 1 prolonged-release tablets (equivalent to 80 mg isosorbide-5-mononitrate), in order for the product to reach its full effect, the second dose should be taken no later than 6 hours after the first dose.

Method and Duration of Administration

The tablets should be taken whole (not chewed) with sufficient liquid (e.g. a glass of water).

Treatment should be initiated at a low dose and slowly titrated up to the required level.

Duration of use is decided by the treating physician. Any discontinuation of therapy with ISMO 40 retard should be gradual and not abrupt, as rebound phenomena cannot be excluded.

Symptoms

A fall in blood pressure with orthostatic dysregulation, reflex tachycardia and headache, asthenia, dizziness, stupor, flush, nausea, vomiting and diarrhoea may occur.

At high doses (more than 20 mg/kg body weight), methaemoglobin formation, cyanosis, dyspnoea and tachypnoea can be expected, as a result of the nitrite ion formed when ISMN is degraded.

At very high doses, increased intracranial pressure with cerebral symptoms may occur.

In cases of chronic overdose, increased methaemoglobin levels have been measured, the clinical relevance of which is debated.

Treatment

In addition to general procedures, such as gastric lavage and keeping the patient horizontal with the legs raised, vital parameters must be monitored under intensive care conditions and corrected where necessary.

In the event of marked hypotension and/or shock, volume replacement should be given; in exceptional cases, norepinephrine and/or dopamine can be infused as circulatory therapy. Administration of epinephrine and related substances is contraindicated.

For methaemoglobinaemia, the following antidotes are available, depending on the degree of severity:

1. Vitamin C: 1 g p.o. or, as sodium salt i.v.
2. Methylene blue: Up to 50 ml of a 1% methylene blue solution i.v.
3. Toluidine blue: Initially, 2-4 mg/kg body weight, strictly via the intravenous route; if required, administration of 2 mg/kg body weight can be repeated several times at 1-hourly intervals.
4. Oxygen therapy, haemodialysis, exchange transfusion.

The Poisons Information Centre, telephone number 0800 764 766 in New Zealand, should be contacted for advice on management.

3 years (36 months).

Do not use after the expiry date shown on the pack.

Store below 30ºC.

ISMO 40 retard is supplied in blister packs of 30 tablets.

No special precautions required.