Prontalgine is an over-the-counter headache medication sold in France. It contains acetaminophen, codeine and caffeine. The combination of these medications is effective at treating tension headaches due to their anti-inflammatory effects, as well as vascular dilation. Acetaminophen is commonly added to codeine, an opiate, to intensify its pain killing effects. Prontalgine is generally safe if taken as directed and for no longer than a few days at a time. Prontalgine can cause mild to serious side effects depending on dose and duration of treatment.
One of the more serious possible side effects of taking prontalgine is damage to the liver. Because prontalgine contains acetaminophen, patients should limit their dose and duration. Acetaminophen has been linked to several negative effects on the liver, including acute liver failure, yellowing of the skin and eyes, inflammation and scarring. In the December 2005 issue of "Hepatology," Dr. Anne Larson and associates found that acetaminophen is the leading cause of acute liver failure in the United States, accounting for 42 percent of cases. In addition, 63 percent of the same patients were taking narcotic-containing compounds similar to prontalgine. The average dose of acetaminophen causing acute liver failure was 24 grams, or approximately 50 prontalgine tablets per day. According to Harvard Medical School, as little as 5,000 mg per day can cause liver failure, further limiting the number of prontalgine tablets a person should take.
Prontalgine can also cause insomnia in some patients, especially if the medication is taken at night. Both caffeine and codeine have properties that inhibit sleep. In the December 2009 issue of "Anesthesiology," Dr. Max Kelz and Jason Moore state that opiates, such as codeine, can cause insomnia because they inhibit adenosine, a neurotransmitter-nucleotide essential for initiating sleep. This effect can be further worsened because the caffeine in prontalgine also inhibits adenosine. In the July 2005 issue of "Cellscience Reviews," Dr. Charles Mobb reported that caffeine directly reduces the duration and onset of sleep through inhibition of adenosine. In addition, caffeine may cause patients to wake up during the night due to bladder constriction, causing an increase in the frequency of urination.
Patients taking prontalgine may also experience nausea. All three of the ingredients in prontalgine can cause nausea for different reasons. According to Dr. David Weissman at the medical College of Wisconsin, opiates like codeine cause nausea in three different parts of the body. Codeine alerts the chemoreceptor trigger zone, which filters out noxious substances in the blood. Codeine also alters the vestibular apparatus, which regulates balance and coordination. Additionally, codeine causes paralysis of the stomach and intestines, reducing motility significantly. According to Drugs.com, one of the most commonly reported side effect of caffeine is nausea. Acetaminophen usually only causes nausea in high doses.