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All price changes →Indications & Uses
Primaquine Phosphate is indicated for the symptomatic relief of allergic conditions, including radical cure of vivax and ovale malaria, use as a gametocytocidal drug in P. falciparum infections, and terminal prophylaxis after leaving a malarious area.
Pharmacology
Primaquine Phosphate is an 8-aminoquinoline derivative. It's given by mouth to produce radical cure and to prevent relapse of vivax and ovale malarias after treatment with a blood schizontocide. It has also been used to prevent transmission of falciparum malaria by people returning to areas where there is a potential for re-introduction of malaria.
Presystemic metabolism is extensive. The plasma half-life ranges from 4 to 10 hours, with a mean of 6 hours. The tmax is about 1 to 2 hours, and plasma protein binding is high.
Dosage Reference
Reference Information Only
Dosages shown are general references from official sources. Always consult your doctor or pharmacist for personalized dosing.
Adults:
The dose of primaquine depends on why it is being used and on the patient's glucose-6-phosphate dehydrogenase (G6PD) status. Terminal prophylaxis with primaquine is only for a selected group of travellers, for example those who have had prolonged exposure in malaria endemic areas. For the radical cure of vivax and ovale malaria, primaquine should be given after appropriate treatment with chloroquine. The usual adult dose to prevent relapse is 15 mg base daily for 14 days. A higher dose of 30 mg base daily for 14 days can be given for less sensitive strains of the parasite, as long as the patient's G6PD is normal, but this higher 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 caused by primaquine is less when the medicine is given at intervals instead of daily. So the preferred regimen is 45 mg base once weekly for 8 weeks, or 30 mg base once weekly for 15 weeks, depending on the type of G6PD deficiency. Strict medical supervision is essential. As a gametocytocide in P. falciparum, adults are given a single dose of 30 to 40 mg base. Because primaquine is relatively toxic, it should not be given to children under one year of age. Older children can receive it, but only under careful medical supervision.
Side Effects
Side effects from primaquine at normal therapeutic doses are usually minimal. Abdominal pain and gastric distress are more common when primaquine is taken on an empty stomach. Larger doses may cause nausea and vomiting. Methaemoglobinaemia may occur occasionally. People with a deficiency of G6PD can develop haemolytic anaemia. Other uncommon effects are mild anaemia and leucocytosis. Hypertension and cardiac arrhythmias have been reported on rare occasions.
Cautions & Contraindications
Warnings & Precautions
Use Primaquine Phosphate with caution in patients who have a systemic disease with a tendency to granulocytopenia, and in those with known or suspected G6PD deficiency. If signs of haemolysis or methaemoglobinaemia appear, stop the medicine. The blood count should also be checked from time to time.
Contraindications
Primaquine phosphate must not be used during pregnancy or while breastfeeding. It is also not suitable during acute flare-ups of systemic diseases that tend to cause granulocytopenia, for example rheumatoid arthritis and lupus erythematosus. And it should not be taken together with other drugs that might cause haemolysis or bone marrow depression.
Pregnancy & Breastfeeding
Primaquine Phosphate must not be used in pregnancy. It can cross the placenta and reach a foetus that is G6PD-deficient, and this may cause haemolytic anaemia in utero. The medicine also enters breast milk, so mothers who are taking it should not breast-feed.
⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
Overdose
An overdose of Primaquine Phosphate can cause abdominal cramps, vomiting and a burning discomfort in the upper stomach (epigastric area). It can also disturb the central nervous system and the cardiovascular system, including cardiac arrhythmia and QT interval prolongation. Other effects are cyanosis, methemoglobinemia, moderate leukocytosis or leukopenia, and anemia.
The most striking symptoms are granulocytopenia, and acute hemolytic anemia in patients with G6PD deficiency. Acute hemolysis does occur, but patients recover completely if the dosage is stopped.
⚠️ In an emergency call 999 or go to the nearest hospital emergency department.
Drug Interactions
Common questions about P Phos 15 mg
What is P Phos 15 mg Tablet?
P Phos 15 mg Tablet is a medicine that contains Primaquine Phosphate. It is made by Hudson Pharmaceuticals Ltd. It belongs to the Anti-malarial drugs group of medicines.
What is P Phos used for?
Primaquine Phosphate is indicated for the symptomatic relief of allergic conditions, including radical cure of vivax and ovale malaria, use as a gametocytocidal drug in P. falciparum infections, and terminal prophylaxis after leaving a malarious area.
What are the side effects of P Phos?
Side effects from primaquine at normal therapeutic doses are usually minimal. Abdominal pain and gastric distress are more common when primaquine is taken on an empty stomach.
Can I take P Phos during pregnancy or while breastfeeding?
Primaquine Phosphate must not be used in pregnancy. It can cross the placenta and reach a foetus that is G6PD-deficient, and this may cause haemolytic anaemia in utero. Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
What happens if I take too much P Phos?
An overdose of Primaquine Phosphate can cause abdominal cramps, vomiting and a burning discomfort in the upper stomach (epigastric area). It can also disturb the central nervous system and the cardiovascular system, including cardiac arrhythmia and QT interval prolongation. In an emergency call 999 or go to the nearest hospital emergency department.
Can I take other medicines with P Phos?
Some medicines can interact with Primaquine Phosphate, for example: Chloroquine. Tell your doctor or pharmacist about every medicine you take.
Is there a cheaper medicine with the same ingredient?
P Phos is already among the lowest-priced brands of Primaquine Phosphate at this strength.
Do I need a prescription for P Phos?
P Phos is a prescription (Rx) medicine. Take it as your doctor advises.