Malarone Side Effects: What to Expect and When to Call Your Doctor

Malarone (atovaquone/proguanil) has one of the best tolerability profiles among antimalarial medications. Most people who take it experience few or no side effects. But like any medication, it can cause side effects — and a small number can be serious. Here's what to expect.

Common Side Effects of Malarone

The most frequently reported side effects of Malarone are gastrointestinal. They are more common and more pronounced at the higher treatment dose (4 tablets daily) than at the lower prophylaxis dose (1 tablet daily):

• Abdominal pain: Occurs in 5-17% of patients (more common at treatment doses)
• Nausea: 3-12% of patients
• Vomiting: 1-12% of patients
• Diarrhea: 4-8% of patients
• Headache, dizziness: Reported; more common during malaria treatment
• Mouth ulcers (stomatitis): About 6% of patients
• Decreased appetite: About 5% of patients

The best way to prevent gastrointestinal side effects is to always take Malarone with food or a milky drink. The FDA prescribing information specifically states this is required for adequate absorption and tolerability. Never take Malarone on an empty stomach.

What to Do If You Vomit Within 1 Hour of Your Dose

If you vomit within 1 hour of taking your Malarone dose, take a repeat dose as soon as possible. If vomiting continues, contact your doctor. Malaria prophylaxis is only effective when the medication is fully absorbed, so missed or unabsorbed doses can leave you unprotected.

Serious Side Effects: Rare but Important

Malarone can cause rare but serious adverse reactions. These are uncommon but require immediate medical attention:

• Severe cutaneous adverse reactions (SCARs) — Stevens-Johnson syndrome (SJS), Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), and erythema multiforme have been reported. These can be life-threatening. Stop Malarone immediately and seek emergency care if you develop a severe rash, blistering, skin peeling, mouth sores, eye redness, or fever with rash.
• Hepatitis and elevated liver enzymes — Liver problems have been reported with prophylactic use. Rarely, hepatic failure requiring liver transplant has occurred. Contact your doctor if you develop yellowing of skin or eyes (jaundice), dark urine, pale stools, or persistent fatigue.
• Allergic reactions — Anaphylaxis, angioedema, and urticaria have been reported. Seek emergency care for difficulty swallowing, swelling of face/lips/tongue, hives, or difficulty breathing.
• Neurological effects — Rare cases of seizures and psychotic events (including hallucinations) have been reported. Call 911 or go to an emergency room if you experience these.
• Blood disorders — Neutropenia, anemia, and pancytopenia (especially in patients with severe kidney disease) have been reported. This is why Malarone is contraindicated for prophylaxis in patients with CrCl < 30 mL/min.

Sun Sensitivity: A Practical Concern for Travelers

Malarone can make your skin more sensitive to sunlight than usual. Since travelers taking Malarone are often visiting sunny tropical destinations, this is worth knowing about. Wear sunscreen (SPF 30+), protective clothing, and a hat. The photosensitivity is generally mild and much less pronounced than with doxycycline, another common antimalarial.

When to Call Your Doctor

Contact your healthcare provider if:

• Nausea, vomiting, or diarrhea is severe or persistent despite taking the medication with food
• You develop yellowing of your skin or eyes, dark urine, or pale stools (signs of liver problems)
• You develop any skin rash, especially with fever or mouth sores (possible SCARs)
• You develop a fever during or after your trip — fever may indicate malaria, not just a side effect

How Malarone Compares to Other Antimalarials in Side Effects

Compared to mefloquine (which carries an FDA boxed warning for neuropsychiatric effects including depression, anxiety, and psychosis) and doxycycline (which causes significant photosensitivity and GI upset), Malarone is generally considered the best-tolerated antimalarial option. If you're experiencing unacceptable side effects, talk to your doctor before stopping Malarone — abruptly stopping your antimalarial before completing the post-travel course can leave you vulnerable. See our guide on alternatives to Malarone for more context.

If you're still searching for Malarone or need help finding it at a pharmacy, medfinder can call pharmacies near you to find which ones have it in stock.