Mepron Side Effects

Generic Name: atovaquone

Note: This page contains information about the side effects of atovaquone. Some of the dosage forms included on this document may not apply to the brand name Mepron.

Not all side effects for Mepron may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to atovaquone: oral suspension, oral tablet

In addition to its needed effects, some unwanted effects may be caused by atovaquone (the active ingredient contained in Mepron). In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking atovaquone:

More common
  • Cough or hoarseness
  • difficult or labored breathing
  • fever or chills
  • lower back or side pain
  • painful or difficult urination
  • shortness of breath
  • tightness in chest
  • wheezing
Incidence not known
  • Black, tarry stools
  • bleeding gums
  • bloating
  • blood in urine or stools
  • bluish-colored lips, fingernails, or palms
  • constipation
  • dark urine
  • dizziness or lightheadedness
  • fast heartbeat
  • headache
  • indigestion
  • large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • light-colored stools
  • loss of appetite
  • nausea
  • noisy breathing
  • pains in stomach, side, or abdomen, possibly radiating to the back
  • pale skin
  • pinpoint red spots on skin
  • rapid heart rate
  • sore throat
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • vomiting
  • yellow eyes or skin

Some of the side effects that can occur with atovaquone may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Abdominal or stomach pain
  • diarrhea
  • lack or loss of strength
  • runny nose
  • skin rash
  • sleeplessness
  • sneezing
  • sore mouth or tongue
  • stuffy nose
  • sweating
  • trouble in sleeping
  • unable to sleep
  • white patches in mouth, tongue, or throat
Incidence not known
  • Blistering, peeling, or loosening of skin
  • eye irritation or redness
  • itching
  • joint or muscle pain
  • red skin lesions, often with a purple center
  • skin rash

For Healthcare Professionals

Applies to atovaquone: oral suspension


In PCP prevention studies comparing atovaquone (the active ingredient contained in Mepron) to inhaled pentamidine, 16% to 25% of patients discontinued atovaquone and 7% discontinued pentamidine due to adverse events. Rash (6%), diarrhea (4%), and nausea (3%) were the most common reasons for discontinuing atovaquone, while bronchospasm (2%) was the most common reason for discontinuing pentamidine. In studies comparing atovaquone to dapsone, treatment-limiting hypersensitivity reactions were more frequent in the dapsone group (16.1%) and treatment-limiting gastrointestinal side effects were more common in the atovaquone group (up to 4.1%).

In PCP treatment studies, 9% of patients discontinued atovaquone due to side effects, compared to 24% of patients receiving sulfamethoxazole-trimethoprim. The most common reason for discontinuation in both treatment groups was rash (atovaquone, 4%; sulfamethoxazole-trimethoprim, 8%). In studies comparing intravenous pentamidine and atovaquone, 63% of patients in the atovaquone group and 72% of patients in the pentamidine group reported side effects. Treatment was discontinued in 7% of the atovaquone patients and 41% of the pentamidine patients due to adverse events; the most common reasons were rash (4%) in the atovaquone group and hypoglycemia (11%) and vomiting (9%) in the pentamidine group.


Gastrointestinal side effects are among the most common and have included nausea (up to 40%), diarrhea (up to 42%), vomiting (up to 22%), abdominal pain (up to 21%), oral monilia (up to 10%), taste perversion (3%), and constipation (3%). The incidence of side effects was higher in patients in PCP treatment studies than in prevention studies. Seven percent of patients experience anorexia and 5% of patients experience dyspepsia, although these are difficult to attribute to the drug due to the serious underlying diseases in the patients who receive atovaquone (the active ingredient contained in Mepron) Hyperamylasemia has been reported in 8% of patients. Pancreatitis has also been reported during postmarketing experience.


Dermatologic side effects have included rash (up to 46%), pruritus (greater than or equal to 10%), exfoliative dermatitis, photosensitivity, and toxic epidermal necrolysis. Erythema multiforme, Stevens-Johnson syndrome, and skin desquamation have been reported during postmarketing experience in patients receiving multiple drug treatment including atovaquone (the active ingredient contained in Mepron)


Hepatic side effects have included elevated ALT (greater than 5 times ULN, 6%), elevated AST (greater than 5 times ULN, 4%), elevated alkaline phosphatase (greater than 2.5 times ULN, up to 8%), and increased amylase (greater than 1.5 times ULN, up to 8%) in patients being treated for PCP. Therapy was discontinued in 2% of patients receiving atovaquone (the active ingredient contained in Mepron) due to ALT/AST elevations, compared to 7% of patients being treated with sulfamethoxazole-trimethoprim. Hepatomegaly has also been reported. Rarely, hepatitis and at least one case of fatal liver failure have been reported during postmarketing experience.


Hematologic side effects have included anemia (up to 6%) and neutropenia (up to 5%), but may be due to underlying disease. Methemoglobinemia and thrombocytopenia have also been reported.


Metabolic side effects have included hyponatremia (up to 10%), hyperglycemia (9%), and hypoglycemia (1%).


Other side effects have included fever (up to 40%), asthenia (up to 31%), flu syndrome (greater than or equal to 10%), pain (greater than or equal to 10%), infection (up to 22%), sweating (greater than or equal to 10%), and malaise, but some may be due to underlying disease. Fatigue, night sweats, and burning sensation of the tongue have also been reported.


Respiratory side effects have included dyspnea (up to 21%), increased cough (up to 25%), rhinitis (up to 24%), sinusitis (greater than or equal to 10%), bronchospasm (up to 4%), and pneumonia.

Nervous system

Nervous system side effects have included insomnia (up to 19%), dizziness (up to 8%), headache (up to 31%), anxiety (7%), and depression (greater than or equal to 10%).


Musculoskeletal side effects have included myalgia (greater than or equal to 10%).


Hypersensitivity reactions have included rash, erythema multiforme, exfoliative dermatitis, and allergic reactions (unspecified, up to 1.1%).


Renal side effects have included elevated creatinine (1%) and elevated BUN (1%). Acute renal impairment has been reported during postmarketing experience.


Cardiovascular side effects have included hypotension (1%).


Ocular side effects have included vortex keratopathy during postmarketing experience.


Immunologic side effects have included hypersensitivity reactions including angioedema, bronchospasm, throat tightness, and urticaria during postmarketing experience.

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