Lil' Wayne remains in critical condition. His condition may have been caused by a combination of drugs.

Lil’ Wayne remains in critical condition. His condition may have been caused by a combination of drugs.

Lil’ Wayne’s extreme convulsions and life-threatening condition is unlikely to have been caused by codeine alone, because of the nature of the drug. But it can fatal if it triggers an allergic reaction or is taken in combination with other drugs.

Codeine is a mild opiate that is usually added to liquid Tylenol for moderate pain relief. An abuser quickly builds up tolerance to the drug, and it may require massive amounts to create the same level of high for habitual users, according to medical references.

A lethal dose is 800 mg, according to a pharmacologist and addiction specialist. But codeine stops becoming effective after the dosage reaches 350mg to 450mg because they liver can’t process it fast enough to produce its by-product, morphine, which actually produces the high.

About 200mg of codeine is equivalent to 10mg of IM Morphine or 30mg of oral Morphine, according to the medical specialist.

Although prescriptions vary, a typical dosage (one teaspoon full) in syrup form includes less than 10mg of codeine, while a bottle might contain 200mg to 250mg of codeine.

But if Wayne was drinking liquid codeine and Tylenol, aka Acetaminophen, the latter could produce far more damaging effects. High amounts of Tylenol combined with alcohol can quickly cause liver damage and cause the liver to fail, which could lead to seizures.

Update: Lil’ Wayne Stable After Suspected Overdose; Still in Intensive Care

Exceeding even 2g of Acetaminophen daily can lead to problems if combined with alcohol.

For someone who has built up a tolerance to codeine, it is very difficult to overdose, according to the addiction specialist. The so-called “red-zone” for people without a tolerance, would be at least 400 mg.

Codeine-laced cough syrup is known as Sizzurp on the street and is usually mixed with a soft drink like Sprite and consumed to get high. Another active drug, Promethazine, a powerful antihistamine used to treat colds, is also usually contained in the syrup.

Promethazine is sleep-inducing, according to medical references, and creates more euphoric effect when taken in excess with codeine. Side effects, although rare, include seizures. The street price of an 8oz bottle of promethazine with codeine is reportedly about $200.