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Mephenytoin Side Effects

The most commonly reported side effects of mephenytoin include headache, maternal exposure timing unspecified, and patent ductus arteriosus, based on 28 FDA adverse event reports from 2004 to 2021. 7.1% of reports found the drug to be ineffective.

Mephenytoin side effects

Percentages show how often each reaction appears relative to total reports for mephenytoin.

1
Headache14.3%4
2
Maternal Exposure Timing Unspecified14.3%4
3
Patent Ductus Arteriosus14.3%4
4
Syndactyly14.3%4
5
Microtia14.3%4
6
Cleft Lip10.7%3
7
Choanal Atresia10.7%3
8
Coloboma10.7%3
9
Foetal Exposure During Pregnancy10.7%3
10
Death7.1%2
11
Agitation7.1%2
12
Suicidal Ideation7.1%2
13
Tremor7.1%2
14
Drug Ineffective7.1%2
15
Cleft Palate7.1%2

These are voluntary reports and do not establish that mephenytoin caused these reactions.

Report severity

89.3%Serious25 reports
25.0%Hospitalizations7 reports
10.7%Fatal3 reports

Seriousness is determined by the reporter, not by OpenClaim.

Mephenytoin drug interactions

Other drugs that appear in adverse event reports alongside mephenytoin. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Phenytoin42.9%12
2
Diazepam32.1%9
3
Primidone25.0%7
4
Carbamazepine17.9%5
5
Oxcarbazepine7.1%2
6
Valproic-acid7.1%2
7
Moxifloxacin-hydrochloride7.1%2
8
Amiloride-hydrochloride3.6%1
9
Hydrochlorothiazide3.6%1
10
Fentanyl3.6%1
11
Eszopiclone3.6%1
12
Metharbital3.6%1
13
Ertapenem-sodium3.6%1
14
Lisinopril3.6%1
15
Trimethadione3.6%1

Taken alongside

1
Diazepam7.1%2
2
Folic-acid7.1%2
3
Levothyroxine-sodium7.1%2
4
Pantoprazole-sodium7.1%2
5
Carbamazepine7.1%2
6
Levetiracetam7.1%2
7
Glycopyrrolate3.6%1
8
Albuterol3.6%1
9
Hydromorphone-hydrochloride3.6%1
10
Theophylline3.6%1
11
Paroxetine3.6%1
12
Acetazolamide3.6%1
13
Darifenacin-hydrobromide3.6%1
14
Trazodone-hydrochloride3.6%1
15
Thiamine3.6%1

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports mephenytoin side effects

50.0% of mephenytoin adverse event reports involve female patients and 10.7% involve male patients. The largest age group is adult at 64%. These figures reflect who reports side effects, not underlying risk.

Sex

Female50.0%
Male10.7%
Unknown39.3%

Age group

< 214.3%
2–110.0%
12–177.1%
18–6464.3%
65+14.3%

What is mephenytoin used for

Conditions and purposes for which patients were taking mephenytoin when the adverse event was reported.

EpilepsyFoetal Exposure During PregnancyMaternal Exposure During PregnancyMaternal Exposure Timing UnspecifiedMyasthenia GravisPartial SeizuresPetit Mal EpilepsyProphylaxis

Mephenytoin brand names and reporting trend

Mephenytoin is sold under the brand name Mesantoin.

Brand names

Mesantoin15

Quarterly reports (20042021)

20042021

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking mephenytoin with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.