Anti-malarial drugs are medicines that treat or prevent malaria, a disease that occurs in tropical, subtropical, and some temperate regions of the world. The disease is caused by a parasite, Plasmodium, which belongs to a group of organism known as protozoa. The only way to get malaria is to be bitten by a certain type of mosquito that has bitten someone who has the disease.
Anti-malarial drugs may cause lightheadedness, dizziness, blurred vision and other vision changes. Anyone who takes these drugs should not drive, use machines or do anything else that might be dangerous until they have found out how the drugs affect them.
The antimalarial drug mefloquine (Lariam) has received attention because of reports that it causes panic attacks, hallucinations, anxiety, depression, paranoia, and other mental and mood changes, sometimes lasting for months after the last dose. Anyone who has unexplained anxiety, depression, restlessness, confusion, or other troubling mental or mood changes after taking mefloquine should call a physician right away. Switching to a different antimalarial drug may be an alternative and can allow the side effects to stop.
Patients who take this medicine over a long time need to have a physician check them periodically for unwanted side effects.
High doses of the anti-malarial drug pyrimethamine may cause blood problems that can interfere with healing and increase the risk of infection. People taking this drug should be careful not to injure their gums when brushing or flossing their teeth or using toothpicks. If possible, dental work should be postponed until treatment is complete and the blood has returned to normal.
The most common side effects of antimalarial drugs are diarrhea, nausea or vomiting, stomach cramps or pain, loss of appetite, headache, itching, difficulty concentrating, dizziness, lightheadedness, and sleep problems. These problems usually go away as the body adjusts to the drug and do not require medical treatment. Less common side effects, such as hair loss or loss of color in the hair; skin rash; or blue-black discoloration of the skin, fingernails, or inside of the mouth also may occur and do not need medical attention unless they are long-lasting.
More serious side effects are not common, but may occur. If any of the following side effects occur, check with the physician immediately:
- Blurred vision or any other vision changes
- Mood or mental changes
- Weakness or unusual tiredness
- Unusual bruising or bleeding
- Hearing loss or ringing or buzzing in the ears
- Fever, with or without sore throat
- Slow heartbeat
Other rare side effects may occur. Anyone who has unusual symptoms after taking an anti-malarial drug should get in touch with his/her physician.
Some anti-malarial drugs may interact with other medicines. When this happens, the effects of one or both of the drugs may change or the risk of side effects may be greater. Anyone who takes antimalarial drugs should let the physician know all other medicines he/she is taking. Among the drugs that interact with some antimalarial drugs are:
- Beta blockers such as atenolol (Tenormin), propranolol (Inderal), and metoprolol (Lopressor)
- Calcium channel blockers such as diltiazem (Cardizem), nicardipene (Cardene), and nifedipine (Procardia)
- Other Anti-malarial drugs
- Quinidine, used to treat abnormal heart rhythms
- Anti-seizure medicines such as vaproic acid derivatives (Depakote or Depakene)
- Oral typhoid vaccine
- Diabetes medicines taken by mouth
- Sulfonamides (sulfa drugs)
- Vitamin K
- Anticancer drugs
The list above does not include all the medicines that may interact with antimalarial drug. Make sure to check with your doctor before taking any antimalarial drugs.