This is indicated for the treatment of pain and fever in patients with the risk of liver toxicity.

Paracetamol (Acetaminophen) is thought to act primarily in the CNS, increasing the pain threshold by inhibiting both isoforms of cyclooxygenase, COX-1, COX-2, and COX-3 enzymes involved in prostaglandin (PG) synthesis. Unlike NSAIDs, acetaminophen does not inhibit cyclooxygenase in peripheral tissues and, thus, has no peripheral anti-inflammatory affects. While aspirin acts as an irreversible inhibitor of COX and directly blocks the enzyme's active site, studies have found that acetaminophen indirectly blocks COX, and that this blockade is ineffective in the presence of peroxides. This might explain why acetaminophen is effective in the central nervous system and in endothelial cells but not in platelets and immune cells which have high levels of peroxides. Studies also report data suggesting that acetaminophen selectively blocks a variant of the COX enzyme that is different from the known variants COX-1 and COX-2. This enzyme is now referred to as COX-3. Its exact mechanism of action is still poorly understood, but future research may provide further insight into how it works. The antipyretic properties of acetaminophen are likely due to direct effects on the heat-regulating centres of the hypothalamus resulting in peripheral vasodilation, sweating and hence heat dissipation.

The mechanism of the possible anti-hepatotoxic activity of L-methionine is not entirely clear. It is thought that metabolism of high doses of acetaminophen in the liver lead to decreased levels of hepatic glutathione and increased oxidative stress. L-methionine is a precursor to L-cysteine. L-cysteine itself may have antioxidant activity. L-cysteine is also a precursor to the antioxidant glutathione. Antioxidant activity of L-methionine and metabolites of L-methionine appear to account for its possible anti-hepatotoxic activity. Recent research suggests that methionine itself has free-radical scavenging activity by virtue of its sulfur, as well as its chelating ability.

Adult dosage: 2 tablets every 4 hours; max. 8 tablets daily.
Child Dosage: Not recommended for children under 12 years of age.

This should not be used with monoamine-oxidase inhibitor (MAOI), antidepressants (e.g. phenelzine). Prolonged use of paracetamol may enhance the effects of anti-clotting/ blood thinning medicines such as warfarin, leading to an increased risk of bleeding. Methionine may reduce the effect of levodopa. Metoclopramide and domperidone increase the rate of absorption of paracetamol from the gut. The absorption of paracetamol is decreased if cholestyramine is taken at the same time.

Children under 12 years of age, Known sensitivity or allergy to any ingredient, Liver disease.

Side effects of recommended doses (up to 8 tablets/capsules a day in adults) are rare, but blood disorders, skin rashes are known to be associated with Napa soft.

Since this is a fixed dose combination of methionine and paracetamol, it is advised to consult with physician before use during the period of pregnancy and lactation.This should be used with caution during pregnancy, and only if the expected benefit to the mother is greater than any possible risk to the foetus. This should be used with caution by breast feeding mothers, and only if the expected benefit to the mother is greater than any possible risk to the baby.

This should be used with caution in alcoholism and decreased kidney function. In cases of overdose, immediate advice should be sought from a physician. Alcohol increases the risk of liver damage that can occur if an overdose of paracetamol is taken. The hazards of paracetamol overdose are greater in persistent heavy drinkers and in people with alcoholic liver disease.

Non opioid analgesics

Store at a cool, dry place, away from light. Keep out of reach of children.