Some factors affecting the absorption of paracetamol

McGilveray, I.J.; Mattok, G. L.

doi:10.1111/j.2042-7158.1972.tb09072.x

Cited by 43 publications

(12 citation statements)

References 7 publications

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“…Absorption of paracetamol is slowed if gastric emptying is delayed by food, posture, certain diseases or drugs, but the bioavailability is not usually decreased (Jaffe et al, 1971;McGilveray & Mattok, 1972;Forrest et al, 1982;Nimmo et al, 1973Nimmo et al, , 1975. However, in the present study, where it was tried to minimize the effect of other factors than migraine, a slight decrease also in the relative bioavailability of paracetamol was found.…”

Section: Discussioncontrasting

confidence: 55%

Effect of migraine attacks on paracetamol absorption.

Tokola¹,

Neuvonen²

1984

Brit J Clinical Pharma

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The absorption of effervescent paracetamol (1000 mg) was investigated in nine female patients during a migraine attack and in the same patients when headache free. Migraine attack decreased (P less than 0.05) the areas under the serum paracetamol concentration‐time curves (AUC) of 0‐2 h, 0‐4 h and 0‐6 h and the peak serum concentration. The severity of nausea correlated significantly with the decrease in the AUC values. Our results support findings of delayed gastric emptying in migraine attacks. Both a delay and an impairment of drug absorption may follow.

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Section: Discussioncontrasting

confidence: 55%

Effect of migraine attacks on paracetamol absorption.

Tokola¹,

Neuvonen²

1984

Brit J Clinical Pharma

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“…In man, paracetamol absorption is negligible from the stomach but very rapid from the small intestine and the rate of absorption therefore depends on the rate of gastric emptying . Absorption is slowed if gastric emptying is delayed by food, posture, disease and drugs such as propantheline and narcotic analgesics, but the total amount absorbed is not decreased (McGilveray & Mattok, 1972;Nimmo, Heading, Wilson, Tothill & Prescott, 1975;.…”

Section: Absorptionmentioning

confidence: 99%

Kinetics and metabolism of paracetamol and phenacetin.

Prescott¹

1980

Brit J Clinical Pharma

393

279

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1 The rate of absorption of oral paracetamol depends on the rate of gastric emptying and is usually rapid and complete. The mean systemic availability is about 757o. 2 Paracetamol is extensively metabolized and the plasma half-life is 1.5-2.5 hours. About 55%o and 3007 of a therapeutic dose is excreted in the urine as glucuronide and sulphate conjugates, respectively, whereas mercapturic acid and cysteine conjugates (representing conversion to a potentially toxic intermediate metabolite) each account for some 4%o of the dose. Paracetamol metabolism is age-and dose-dependent. 3 With hepatotoxic doses, paracetamol metabolism is impaired and the half-life prolonged. Sulphate conjugation is saturated and the proportion excreted as mercapturic acid and cysteine conjugates is increased. 4 The renal clearance of paracetamol depends on urine flow rate by notpH. The renal clearances of' the glucuronide and sulphate conjugates often exceed the glomerular filtration rate and are independent of urine flow and pH. 5 Phenacetin absorption depends on formulation. It is extensively metabolized to paracetamol and minor metabolites are probably responsible for toxicity Paracetamol PARACETAMOL (acetaminophen, N-acetyl-p-aminophenol, 4-hydroxyacetanilide) is a moderately waterand lipid-soluble weak organic acid. It has a pKa value of 9.5 and is therefore largely unionized over the physiological range ofpH.

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“…In studies where paracetamol absorption has been slowed by food, there has been no change in the total amount absorbed [13][14][15]. The present study was carried out to investigate the effect of a vegetarian diet on the absorption and disposition of paracetamol.…”

Section: Introductionmentioning

confidence: 99%

“…The absorption of paracetamol is not impaired in children with protein-energy malnutrition [9] but it may be somewhat slower in obese subjects [12]. Food reduces the rate of absorption of paracetamol [1,2] and the effects vary according to the nature of the meal [13,14].…”

Section: Introductionmentioning

confidence: 99%