The influence of thiethylperazine on the absorption of effervescent aspirin in migraine

Delayed absorption of many (paracetamol, aspirin, other NSAIDs and zolmitriptan) but not all (sumatriptan, rizatriptan) drugs during migraine attacks and most likely normal gastric emptying outside attacks. A review

Background In most pharmacokinetic studies, the oral absorption of drugs is impaired during migraine attacks but exceptions occur. A study on gastric emptying using gastric scintigraphy indicated that gastric stasis also occurs interictally in migraine. These studies were reviewed critically. Results In seven studies, mainly investigating NSAIDs and analgesics, the early absorption of the drugs during 112 migraine attacks was delayed. The absorption of sumatriptan is usual in therapeutic doses, and rizatriptan was normal during 131 migraine attacks. The interictal gastric stasis observed using gastric emptying scintigraphy (GES) with solids ( n = 13) could not be confirmed in a larger study ( n = 27) using the same method. Also gastric emptying measured with GES with liquids ( n = 7) and epigastric impedance ( n = 64) was normal outside migraine attacks. Conclusions and possible clinical implications Drug absorption is not generally impaired during migraine attacks. Gastric emptying is most likely normal in the majority of migraine patients outside attacks. Prokinetic and antiemetic drugs such as metoclopramide and domperidone should not be routinely combined with oral analgesics or oral triptans. If, however, nausea is severe or vomiting occurs, treatment with an antiemetic with proven efficacy on the nausea of migraine can be indicated.

The effect of metoclopramide and prochlorperazine on the absorption of effervescent paracetamol in migraine

Antiemetics modify gastric emptying, a rate-limiting step in drug absorption. The absorption of effervescent paracetamol in water solution was studied in three groups of 10 female patients during acute migraine attacks. Paracetamol was preceded 30 min earlier by a rectal dose of metoclopramide, prochlorperazine maleate, or placebo. Each patient was retested with paracetamol when headache-free. Migraine attacks delayed slightly the absorption of paracetamol solution. Prior administration of rectal prochlorperazine had a minor delaying effect on paracetamol absorption. The peak concentration, the time to reach the peak, and the area under the time-concentration curve from 0 to 6 h of paracetamol were similar with the three treatments.

Potential uses for metoclopramide

Metoclopramide, a dopamine antagonist, is approved in the U.S. for the treatment of various gastrointestinal disorders. Its use has been investigated in a wide variety of diseases, including those not involving the intestinal tract. Although more study is required before routine clinical use of metoclopramide can be advocated, it may be effective in the treatment of tardive dyskinesia, in decreasing the risk factors associated with anesthetic-related aspiration, and as an adjunct in the treatment of gastric bezoars. It also may be used safely in patients with Parkinson's disease. The use of metoclopramide in the treatment of neurogenic bladder, orthostatic hypotension, tumor-associated gastroparesis, nonprolactinemic amenorrhea, failure to thrive, Tourette's syndrome, anorexia nervosa, and hiccups, as well as an adjunct to migraine therapy, has been investigated, but sufficient evidence has not been accumulated to advocate the use of metoclopramide in these disorders.

Metoclopramide. An updated review of its pharmacological properties and clinical use

Since previously reviewed in the Journal (Vol. 12, No. 2), metoclopramide has been confirmed as an effective drug in treating and preventing various types of vomiting and as a useful agent in oesophageal reflux disease, gastroparesis, dyspepsia, and in a variety of functional gastrointestinal disorders. Of considerable importance is the recent evidence of its efficacy when administered intravenously in high dosages in preventing severe vomiting associated with cisplatin. Good results have been achieved in patients not previously treated with cisplatin, but further studies are needed to determine its level of efficacy in patients who have experienced severe vomiting during earlier courses of cytotoxic therapy. Side effects consisting of mild sedation, diarrhoea and reversible extrapyramidal reactions have occurred, but are tolerated by many patients.

A double blind study of metoclopramide in the treatment of migraine attacks

One hundred and fifty patients with migraine attacks attending the Copenhagen acute migraine clinic were treated either with metoclopramide 10 mg i.m. metoclopramide 20 mg as suppository or placebo in a double blind trial. All patients simultaneously or 30 minutes later received paracetamol 1 g and diazepam 5 mg orally. The nausea was relieved in 71% of the patients by placebo and bed rest, but metoclopramide was significantly (p = 0.04) more effective and relieved nausea in 86% of the patients. Metoclopramide did not by itself reduce the pain, but enhanced the effect of the analgesic or sedative medication. This effect, however, just failed to be statistically significant (p = 0.06).

Migraine and drug absorption

The majority of migraine attacks are associated with gastrointestinal symptoms which add considerably to the distress and inconvenience caused by the headache. When salicylate absorption from effervescent aspirin tablets was studied during migraine, the rate of absorption was found to be reduced relative to that found in non-migrainous volunteers and in the same patients when headache-free. There is evidence that this reduced rate of absorption is caused by gastrointestinal stasis and reduced rate of gastric emptying. Patients in whom aspirin absorption was delayed were more likely to take longer to respond and to require additional treatment. Metoclopramide, which increases gastric emptying rate, has been shown to improve the rate of absorption of aspirin during migraine and also increase the rate of recovery from the attack and avoid the need for additional treatment; effects which were not shown by thiethylperazine. It is likely that delayed absorption during migraine affects some drugs other than aspirin, such as ergotamine, and it is therefore recommended that the most rapidly absorbable formulation should be used. If such treatment is ineffective, metoclopramide may be a useful addition and should be tried before resorting to other routes of administration.