Primacin (Primaquine Phosphate)
Complete patient guide for uses, dosage, side effects, and safety information
Prescription RequiredQuick Facts
What Is Primacin Used For?
Primacin contains primaquine phosphate, an antimalarial medication that fights malaria parasites at different stages of their life cycle, both in your blood and liver.
Primary Uses
Primacin is used to treat vivax and ovale forms of malaria after an attack. It also helps in treating falciparum malaria. Your doctor may prescribe it for other reasons as well.
How It Works
Primacin works by killing the malarial parasite at different stages of its life cycle, targeting parasites both in the blood and in the liver.
Good to know: Primacin is not addictive and is only available with a doctor’s prescription.
How to Take Primacin
Take Primacin exactly as prescribed by your doctor. The dose and treatment length depend on where you were infected with malaria, as some areas have more resistant strains.
Dosage Instructions
For adults: Usually 15 mg daily for 14 days, up to 30 mg daily for 14 days in resistant areas, or treatment may extend to 21 days in South East Asia and Pacific regions. If you have G6PD deficiency: up to 45 mg once weekly for 8 weeks. For falciparum malaria: 45 mg as a single dose. For children: 0.3 mg/kg/day, or 0.7-1.0 mg/kg/day for falciparum malaria. Take with a full glass of water at the same time each day with a meal.
What If You Miss a Dose?
If it’s almost time for your next dose, skip the missed dose and take the next one as scheduled. If there’s still a long time before your next dose, take it as soon as you remember. If you miss more than one dose, contact your doctor.
Important: Never take more than one dose at a time to make up for missed doses – this may increase side effects.
Available Tablet Strengths
Side Effects
Like all medications, this medicine can cause side effects. Most are mild and temporary, but some require medical attention.
Common Side Effects
These side effects occur relatively frequently and usually don’t require emergency care:
- Abdominal cramps and pains
- Nausea
- Vomiting
- Dizziness
- Headache
- Rash
- Itching of the skin
Seek immediate medical attention if you experience:
- Dark-coloured urine
- Irregular heartbeat or slow heart rate
- Feeling tired, weak, confused or sick
- Pale or bluish hue to your skin
- Shortness of breath
- Fever
- Pain, tingling or weakness in your arms or legs
- Sore mouth and gums, mouth ulcers or bleeding gums
- Serious allergic reaction (swelling of face, lips, mouth or throat causing difficulty swallowing or breathing)
Important Warnings
Primacin is not suitable for everyone. There are important conditions and situations where you should not take this medication.
Who Should Not Take Primacin
Do not take Primacin if you have severe glucose-6-phosphate (G6PD) deficiency, are pregnant, have rheumatoid arthritis or lupus erythematosus, are taking quinacrine hydrochloride for malaria, or are taking other medicines that affect red blood cells or bone marrow. Also avoid if allergic to primaquine or other 8-aminoquinolines.
Medical Conditions to Discuss
Tell your doctor if you have NADH methaemoglobin reductase deficiency, heart disease, irregular heartbeats, low heart rate, low potassium or magnesium levels in blood, or recent malaria treatment with quinacrine hydrochloride. Also mention allergies to medicines, foods, preservatives, or dyes.
Pregnancy and Breastfeeding
Do not take if pregnant or planning to become pregnant – safety has not been established. Do not breastfeed while taking this medicine as there is no safety information available.
Elderly Patients: Use with caution if you are over 65 years old as elderly persons are more sensitive to the effects of this medicine.
Drug Interactions
Several medications can interact with Primacin, affecting how well it works or increasing side effects.
- Proguanil (used to treat malaria)
- Medicines that reduce bone marrow’s ability to produce red blood cells and platelets (such as chemotherapy medicines)
- Some medicines used to treat irregular heartbeat
- Ketoconazole (used to treat fungal infections)
- Quinacrine hydrochloride
Alcohol & Driving
The source material does not provide specific information about alcohol consumption or driving while taking Primacin.
Storage
Keep tablets in their original pack until ready to take them. Store in a cool, dry place below 25°C. Do not store in the bathroom, near a sink, on a window sill, or in the car as heat and dampness can damage the medicine. Keep out of reach of children – a locked cupboard at least 1.5 meters above ground is ideal. Do not keep past the expiry date.
Overdose Information
If you think you or someone else has taken too much Primacin, immediately call your doctor, Poisons Information Centre (13 11 26), or go to the nearest hospital emergency department, even if there are no symptoms. Overdose symptoms may include abdominal cramps, vomiting, burning stomach pain, irregular or slow heartbeat, dark urine, feeling tired/weak/dizzy/confused/sick, pale or bluish skin, headache, shortness of breath, fever, pain/tingling/weakness in arms or legs, and sore mouth/gums/ulcers/bleeding gums.
Frequently Asked Questions
Primacin works by killing malarial parasites at different stages of their life cycle. Treatment typically lasts 14 days for most cases, though it may be extended to 21 days in areas with resistant strains like South East Asia and the Pacific region.
Yes, you must take Primacin with a meal. Taking it with food helps prevent an upset stomach. Take it at about the same time each day with a meal for best results.
No, Primacin is not addictive. It is an antimalarial medication that works by killing malarial parasites and does not cause dependence.
If it’s almost time for your next dose, skip the missed dose and take the next one as scheduled. If there’s still a long time before your next dose, take it as soon as you remember. Never take two doses at once to make up for a missed dose, as this may increase side effects.
No, continue taking Primacin for as long as your doctor tells you to, even if you feel better. Complete the full course of treatment as prescribed. If you feel chilly or have fever after returning from a malaria area, see your doctor even if you’ve taken the full course, as relapses can occur.
If you have severe G6PD deficiency, you should not take Primacin. However, if you have mild G6PD deficiency, your doctor may prescribe a different dosing schedule – up to 45 mg once weekly for 8 weeks instead of daily dosing. Your doctor can do a blood test to check for this deficiency.
No, do not take Primacin if you are pregnant or planning to become pregnant. The safety of this medicine during pregnancy has not been established. Also, do not breastfeed while taking this medicine as there is no safety information available for nursing mothers.
Important Disclaimer
This information is intended for general educational purposes only and should not be considered medical advice. Always consult your healthcare provider or pharmacist before starting, stopping, or changing any medication.
If you think you may have a medical emergency, call your doctor or emergency services immediately.