P Phos Tablet

P Phos is indicated for the symptomatic relief of allergic conditions including:

• Radical cure of vivax and ovale malaria
• As a gametocytocidal drug in P. falciparum infections
• Terminal prophylaxis after leaving a malarious area

Each film coated tablet contains Primaquine Phosphate BP 26.4 mg (equiv. to Primaquine 15 mg)

contains Primaquine Phosphate, an 8-aminoquinoline derivative which is given by mouth to produce radical cure and prevent relapse of vivax and ovale malarias following treatment with a blood schizontocide. It has also been used to prevent transmission of falciparum malaria by those returning to areas where there is a potential for re-introduction of malaria.

• Presystemic metabolism: extensive
• Plasma half-life: range 4-10 hours, mean 6 hours
• t_max: about 1 - 2 hours
• Plasma protein binding: high

The dose of primaquine deployed depends upon the indication for use and the glucose-6-phosphate dehydrogenase (G6PD) status of the patient. Terminal prophylaxis with primaquine is indicated only for selected group of travellers e.g. those who have had prolonged exposure in malaria endemic areas. In the radical cure of vivax and ovale malaria, primaquine should be given after appropriate therapy with chloroquine. The conventional adult dose for prevention of relapse is 15 mg base daily for 14 days. Higher doses, 30 mg base daily for 14 days, can be given to deal with less sensitive strains of the parasites, provided the patients G6PD is normal; however, the higher dosage regimen should not be used routinely. A suggested dose for children is 200 to 300 mcg per kg body-weight daily for 14 days.

In patients with G6PD deficiency haemolysis due to primaquine is less when the drug is administered at intervals rather than on a daily basis, so that the preferred regimen is 45 mg base once weekly for 8 weeks, or 30 mg base once weekly for 15 weeks, according to the type of G6PD deficiency. Strict medical supervision is essential.

For use as a gametocytocide in P. falciparum, it is given as a sample dose of 30-40mg base for adults.

use in children: In view of the relative toxicity of primaquine, it should not be given to children under one year of age. Older children can receive primaquine, under careful medical supervision.

P Phos inhibits hepatic drug oxidation and is reported to inhibit the metabolism of chloroquine.

• Pregnancy and lactation.
• In acute exacerbations of systemic diseases, having a tendency to granulocytopenia, e.g. rheumatoid arthritis, and lupus erythematosus.
• Concomitant use with other drugs which might cause haemolysis or bone marrow depression.

Adverse effects with therapeutic doses of primaquine are usually minimal but abdominal pain and gastric distress are more common if administered on an empty stomach. Larger doses may cause nausea and vomiting. Methaemoglobinaemia may occur occasionally. Haemolytic anaemia can occur in persons with a deficiency of G6PD. Other uncommon effects include mild anaemia and leucocytosis. Hypertension and cardiac arrhythmias have been reported on rare occasions.

This drug is contraindicated in pregnancy, because it may be passed transplacentally to a G6PD-deficient foetus and cause haemolytic anaemia in utero. It enters breast milk, and mothers taking the drug should not breast-feed.

It should be used with caution in pateints with systemic disease with a tendency to granulocytopenia, known or suspected G6PD deficiency. P Phos should be withdrawn if signs of haemolysis or methaemoglobinaemia occur and blood count should be monitored periodically.

Symptoms of overdosage of P Phos include abdominal cramps, vomiting, burning epigastric distress, central nervous system and cardiovascular disturbances, including cardiac arrhythmia and QT interval prolongation, cyanosis, methemoglobinemia, moderate leukocytosis or leukopenia, and anemia. The most striking symptoms are granulocytopenia and acute hemolytic anemia in G6PD deficient patients. Acute hemolysis occurs, but patients recover completely if the dosage is discontinued.

Anti-malarial drugs

Store at 25° C. Protect from light.