Potential toxicity should be assessed and a toxicologist consulted when: >200 mg/kg (or 10 g) ingested over a 24 hour period. >150 mg/kg/day (or 6 g) ingested over a 48 hour period.
Paracetamol/Acetaminophen
Recommended paracetamol dose in adults = 4g or 75mg/kg in 24h. Overdose = ingestion >75mg/kg. > 150mg/kg = Lethal.
First you need to convert the mg per kg into total mg by multiplying it by the patient's weight. So for a person who weighs 70kg, 0.5mg per kg is the same as 35mg.
Taking 1 or 2 extra tablets is unlikely to harm you. Do not take more than 8 tablets in 24 hours. Taking too much paracetamol can be dangerous and you may need treatment. Too much paracetamol can cause liver damage.
Serious toxicity may occur in patients who have ingested > 150 mg/kg in any 24 hour period. Rarely, toxicity may occur for ingestions between 75-150 mg/kg.
There may be no symptoms for the first day. A feeling of sickness (nausea) and being sick (vomiting) may occur a few hours after taking the overdose. After 24 hours there may be pain under the ribs on the right side (where the liver is) and there may be yellowing of the whites of the eyes and the skin (jaundice).
Toxicity can be measured by its effects on the target (organism, organ, tissue or cell) or indirectly by measuring altered biological function downstream after acute, subchronic or chronic exposure to a chemical or biological entity. Drug exposure is then used as a proxy or surrogate for the undesirable effects.
A basic formula, solving for x, guides us in the setting up of an equation: D/H x Q = x, or Desired dose (amount) = ordered Dose amount/amount on Hand x Quantity.
HEPATOTOXICITY RISK FACTORS
While acute liver injury can occur when used at or below the recommended daily maximum dose (4000 mg)[4], paracetamol toxicity is often the result of ingestion of paracetamol over this maximum dose.
Paracetamol is a common painkiller that is normally safe. If you take more than the recommended amount (an overdose), it can harm the liver, and occasionally the kidneys.
You should not take more than 8 normal strength tablets in 24 hours (4,000mg). If levels exceed the above paracetamol can cause liver damage (hepatotoxicity) if you take larger doses than recommended. Adults must not take more than 4000 mg in a 24-hour period.
The maximum daily dose of Paracetamol must not exceed 3000 mg. Take 500 mg at a time, up to 2000 mg per 24 hours. The daily dose must not exceed 2000 mg. Not recommended for children under 10 years of age.
The recommended daily dose of paracetamol is approximately 60 mg/kg/day, divided into 4 or 6 daily doses, that is, 15 mg/kg every 6 hours or 10 mg/kg every 4 hours.
Adults can usually take 1 or 2 tablets (500mg) every 4-6 hours, but shouldn't take more than 4g (8 x 500mg tablets) in the space of 24 hours.
However, repeatedly taking more than the recommended dose or overdosing on paracetamol can cause serious injury to the liver and even death. The recommended maximum dose of paracetamol for an adult (or child over 12 years) is 4g in any 24-hour period (equivalent to 8 x 500mg tablets).
Some medications, particularly for children may be prescribed according to the person's body weight (kg) or body surface area (m²). Simply multiply the dose by the weight to determine the dose required which may then be placed in other formula. 2mg / kg of a drug is required in a single dose.
Milligrams to micrograms (mcg) = mg x 1,000; Micrograms to nanograms (ng) = mcg x 1,000; Litres (L) to millilitres (ml) = L x 1,000.
Four methods for calculating drug dosages include basic formula, ratio and proportion, fractional equation, and dimensional analysis. The ratio and proportion and fractional equation methods are similar. For drugs that require individualized dosing, body weight and body surface area are used.
It relies on the concept that a dose, or a time of exposure (to a chemical, drug, or toxic substance), will cause an effect (response) on the exposed organism. Usually, the larger or more intense the dose, the greater the response, or the effect. This is the meaning behind the statement “the dose makes the poison.”
If you take too much Paracetamol your liver may not be able to metabolise it efficiently and this could make you extremely unwell. Paracetamol overdose can lead to liver failure in some people and this is why you need to take careful note of this advice.
Paracetamol overdose can result in liver damage and, at very high dosages, can be fatal.
Paracetamol can also be used to treat fever (high temperature). It's dangerous to take more than the recommended dose of paracetamol. Paracetamol overdose can damage your liver and cause death. Always follow the directions on the packet when using paracetamol.