Drug Interaction:
Succinimides include - Ethosuximide, Methsuximide, Phensuximide Refer- Succinimides
Interacting drugs- summary
Succinamides +
Hydantoins serum hydantoin levels may be increased
Primidone lower primidone and phenobarbital levels may occur
Valproic acid + Succinamide both increases and decreases in succinamide levels have occured
Adverse Reaction:
GI- (frequent )- nausea, vomiting, vague gastric upset, cramps, anorexia, diarrhea, weight loss, epigastric and abdominal pain, constipation
Hematologic- eosinophillia, garnulocytopenia, leukopenia, agranulocytosis, monocytosis, pancytopenia, with or without bone marrow depression.
Miscellaneous- periorbital edema, hyperremia, muscle weakness, swelling of the tongue, hypertrophy.
Contra-Indications:
Hypersensitivity to succinimides
Special precautions-
Grand mal seizures- succinimides when used alone in mixed types ofepilepsy, may increase the frequency of grand mal seizures in some patients
Dosage changes/other medication- it is importnat to proceed slowly with increasing dosage and when adding or eliminating other mediaction. Abrupt withdrawl of other mediaction may precipitate absence (petit mal ) status
Acute intermittant porphyria- use phensuximide with caution.
Warnings-
Histologic effects- blood dyscrasias, some fatal have occure, therefore perform periuodic blood counts. Should signs or symptoms of infection (eg sore thgroat, fever) develop, consider blood counts at that point.
Lupus- cases of systemic lupus erythematosus have occured
Renal/hepatic function impairment- succinimides have produced morphological and functional changes in animal liver.
Abnormal liver nad renal functions have been reported in humans. For this reason administer with extrteme caution to patients with known or liver diseases. perform periodic urinalysis and liver function studies for all patients receiving this drug.
Pregnancy- consider discontinuation of anticonvulsants prior to and during pregnancy when the nature, frequency and severity of the seizures do not pose a serious threat to the patient.
Dosages/ Overdosage Etc:
Dosage-
The therapeutic range of ethosuximide serum levels is 40 to 100mcg/ml.
Overdosage-
Symptoms
Acute overdosage-
Confusion, sleepiness,unsteadiness. flaccid muscles, comaith slow, shallow respiration,hypotension, cyanosis, hypo-or hyperthermia,absent reflexes, nausea, vomiting, CNS depression including coma with respiratory depression.
Chronic overdosage-
Skin rash, confusion, ataxia, dizziness, drowsiness, hangover, depression,irritability, por judgement, periorbital edema, proteinuria,hepatic dysfunction, fatal bone marrow aplasia, delayed onset of coma nausea, vomiting, muscular weakness, hematuria,casts,nephrosis.
Treatment
1. Includes usual supportive measures.
2. Charcoal hemoperfusion may be indicated.
3. Hemodialysis may be useful for ethosuximide
4. Forced diuresis and exchange transfusions are ineffective
Missed dose-
1. If you miss a dose of this medicine, take it as soon as possible.
2. However, if it is almost time for next dose, skip the missed dose and go back to your regular dosing schedule.
3. Do not double doses.
Patient Information:
Succinamide Anticonvulsants- Systemic
1. If GI upset occurs, take with food or milk.
2. Do not discontinue medicaton abruptly or change dosage, except on adviceof physician
3. Patient should carry identification (Medic Alert) indicating medication, usuage and epilepsy
4.May cause drowsiness, diziness, or blurred vision, aclohol may exacerbate these effects
. 5. Use caution while driving or performing other tasks requiring alertness,coordination or physical dexterity
6. Notify physician if any of the folowing occurs- skin rash, joint pain, unexplained fever, sore throat, unusual bleeding or brusing, drowsiness, dizziness, blurred vision or pregnancy
7. Phensuximide may discolor the urine red or red-brown. This is not harmful.
8.Allergies-
Tell your doctor if you have ever had any unusual or allergic reaction to anticonvulsant
medicines. Also tell your healthcare provider if you allergic to any other substances,
such as preservatives.
9.Pregnancy-
Although succinamides anticonvulsants have not shown to cause problems in humans,
there have been unproven reports of increased birth defects associated with the use
of other anticonvulsant medicines
10. Breast-feeding-
Ethosuximide passes into breast milk. It is not known whether methsuximide or
phensuximide passes into breast milk . However, these medicines have not been
reported to cause problems in nursing babies
11.Children-
Succinimide anticonvulsants are not expected to cause different side effects or
problems in children than in adults.
12.Older adults-
Many medicines have not been studied specifically in older people. Therefore, it
may not be known whether they work exactly the same way they do in younger
adults, or if they cause different side effects or problems in older people
. Although there is no specific information comparing use of succinnamide
anticonvulsants in the elderly to use in other age groups, they are not expected
to cause different side effects or problems in older people than they do in
younger adults
13.Other medicines-
Although certain medicines should not be used together at all, in other cases two
different medicines may be used together even interaction might occur. In such
cases your doctor may want to change the dose , or other precautions may be
necessary.
When you are taking succinamide anticonvulsants it is especially important that
your doctor know if you are taking any of the following-
Central nervous system (CNS) depressants(medicines that cause drowsiness)-
using these medicines together may increase CNS depressant effects.
Haloperidol- (eg.Halidol) - a change in pattern and or frequency of seizures may
occur, the dose of either medicine may need to be changed
14. Other medical problems-
Presence of other medical problems may affect the use of succinamide
anticonvulsants. Make sure you tell your doctor if you have any other
medical problems-
Blood disease or
Intermittant porphyria or
Kidney disease (severe) or
Liver disease - succinamide anticonvulsants may make the condition worse.
Pharmacology/ Pharmacokinetics:
Pharmacology-
Succinimides suppress the paroxysmal three cycle per second spike wave activity associated with lapses of consciousness common in absence (petit mal ) seizures. The frequency of epileptiform atacks is reduced apparently by motorcortex depression and elevation of the threshold of the CNS to convulsive stimuli.
Pharmacokinetics-
These agents are readily absorbed from the GI tract. Peak serum levels of ethosuximides are acheived in 3 to 7 hours peak levels of methosuximide and phensuximide are reached in 1 to 4 hours.
Pregnancy and lactation:
Pregnancy-
Consider discontinuation of anticonvulsants prior to and during pregnancy when the nature , frequency and severity of the seizures do not pose a serious threat to the pastient.
