• Antiprotozoal

Primaquine ( PRIM-a-kween) belongs to the group of medicines called antiprotozoals. It is used in the treatment of malaria, a red blood cell infection transmitted by the bite of a mosquito.

Malaria transmission occurs in large areas of Central and South America, Hispaniola, sub-Saharan Africa, the Indian subcontinent, Southeast Asia, the Middle East, and Oceania. Country-specific information on malaria can be obtained from the Centers for Disease Control and Prevention (CDC), or from the CDC's web site at http://www.cdc.gov/travel/yellowbk

Primaquine is available only with your doctor's prescription, in the following dosage form:

Oral
• Tablets (U.S. and Canada)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For primaquine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to primaquine or iodoquinol (e.g., Yodoxin). Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Primaquine is not recommended for use during pregnancy.

Breast-feeding—It is not known if primaquine is distributed into breast milk. However, primaquine has not been reported to cause problems in nursing babies.

Children—Children should avoid traveling to areas where there is a chance of getting malaria, unless they can take effective antimalarial medicines such as primaquine.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of primaquine in the elderly with use in other age groups.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking primaquine it is especially important that your health care professional know if you are taking any of the following:

• Acetohydroxamic acid (e.g., Lithostat) or
• Antidiabetics, oral (diabetes medicine you take by mouth) or
• Dapsone or
• Furazolidone (e.g., Furoxone) or
• Methyldopa (e.g., Aldomet) or
• Nitrofurantoin (e.g., Furadantin) or
• Procainamide (e.g., Pronestyl) or
• Quinacrine (e.g., Atabrine) or
• Quinidine (e.g., Quinidex) or
• Quinine (e.g., Quinamm) or
• Sulfonamides (sulfa medicine) or
• Sulfoxone (e.g., Diasone) or
• Vitamin K (e.g., AquaMEPHYTON, Synkayvite)—Taking these medicines with primaquine may increase the chance of side effects affecting the blood

• Family or personal history of favism or hemolytic anemia or
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency or
• Nicotinamide adenine dinucleotide (NADH) methemoglobin reductase deficiency—Patients with any of these medical problems who take primaquine may have an increased chance of side effects affecting the blood

If this medicine upsets your stomach, it may be taken with meals or with antacids . If stomach upset (nausea, vomiting, or stomach pain) continues, check with your doctor.

If you are taking primaquine for malaria, keep taking it for the full time of treatment to help prevent or completely clear up the infection. Do not miss any doses.

Dosing—

The dose of primaquine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of primaquine. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are taking primaquine.

• For the treatment of malaria:
  • Adults and older children: 15 mg once a day for fourteen days.
  • Younger children: Dose is based on body weight and must be determined by the doctor.

Missed dose—

If you do miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Your doctor should check your progress at regular visits to make sure that primaquine is not causing blood problems.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

• More common
  • Back, leg, or stomach pains;  dark urine ;  fever;  loss of appetite ;  pale skin;  unusual tiredness or weakness 
  
  

• Less common
  • Bluish fingernails, lips, or skin;  difficulty breathing;  dizziness or lightheadedness  
  
  

• Rare
  • Sore throat and fever 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Cramps;  nausea or vomiting 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although this use is not included in product labeling, primaquine is used in certain patients with the following medical condition:

• Pneumocystis carinii pneumonia (PCP)

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for this use.