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R-mephobarbital
drug data and news
R-mephobarbital drug data, resources, and news articles (when available). Onconews.org provides news on cancer research. This section, which includes profiles on medicines that may or not be cancer-related is in beta form. If things run smoothly we will be releasing a new format late in the summer of 2006.
| Generic name |
R-mephobarbital
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| Brand Names/Synonyms |
Dea No. 2250; Enfenemal; Enphenemal; Enphenemalum; HSDB 3579; Isonal; Mebaral; Meberal; Mebroin; Menta-Bal; Mephobarbital; Mephobarbital [Jan]; Mephobarbitone; Mephytal; Methyl Phenobarbitone; Methyl-Calminal; Methylphenobarbital; Methylphenobarbitalum [Inn-Latin]; Methylphenobarbitonum; Methylphenolbarbital; Methylphenylbarbituric Acid; Metilfenobarbital [Inn-Spanish]; Metilfenobarbitale [Dcit]; Metylfenemal; Metyna; Morbusan; N-Ethylmethylphenylbarbituric Acid; N-Methylethylphenylbarbituric Acid; N-Methylphenobarbital; N-Methylphenolbarbitol; Phemetone; Phemiton; Phemitone; Phenmiton; Phenobarbital, Mono-Methyl; Prominal |
| Indication |
For the relief of anxiety, tension, and apprehension, also used as an anticonvulsant for the treatment of epilepsy. |
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Description |
Not Available |
| Pharmacology |
R-mephobarbital, a barbiturate, is used in combination with acetaminophen or aspirin and caffeine for its sedative and relaxant effects in the treatment of tension headaches, migraines, and pain. Barbiturates act as nonselective depressants of the central nervous system (CNS), capable of producing all levels of CNS mood alteration from excitation to mild sedation, hypnosis, and deep coma. In sufficiently high therapeutic doses, barbiturates induce anesthesia. |
| Mechanism Of Action |
R-mephobarbital binds at a distinct binding site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl- ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged. |
R-mephobarbital News
(When available) |
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| Dosage Forms |
TABLET |
| Drug_Category |
Hypnotics and Sedatives; Anticonvulsants; ATC:N03AA;ATC:N05CA |
| Absorption |
Approximately 50% of an oral dose of mephobarbital is absorbed from the gastrointestinal tract. |
| Interactions |
Interactions for R-mephobarbital:
Most reports of clinically significant drug interactions occurring with the barbiturates have involved phenobarbital. However, the application of these data to other barbiturates appears valid and warrants serial blood level determinations of the relevant drugs when there are multiple therapies.
1. Anticoagulants: Phenobarbital lowers the plasma levels of dicumarol (name previously used: bishydroxycoumarin) and causes a decrease in anticoagulant activity as measured by the prothrombin time. Barbiturates can induce hepatic microsomal enzymes resulting in increased metabolism and decreased anticoagulant response of oral anticoagulants (eg, warfarin, acenocoumarol, dicumarol, and phenprocoumon). Patients stabilized on anticoagulant therapy may require dosage adjustments if barbiturates are added to or withdrawn from their dosage regimen.
2. Corticosteroids: Barbiturates appear to enhance the metabolism of exogenous corticosteroids probably through the induction of hepatic microsomal enzymes. Patients stabilized on corticosteroid therapy may require dosage adjustments if barbiturates are added to or withdrawn from their dosage regimen.
3. Griseofulvin: Phenobarbital appears to interfere with the absorption of orally administered griseofulvin, thus decreasing its blood level. The effect of the resultant decreased blood levels of griseofulvin on therapeutic response has not been established. However, it would be preferable to avoid concomitant administration of these drugs.
4. Doxycycline: Phenobarbital has been shown to shorten the half-life of doxycycline for as long as 2 weeks after barbiturate therapy is discontinued. This mechanism is probably through the induction of hepatic microsomal enzymes that metabolize the antibiotic. If phenobarbital and doxycycline are administered concurrently, the clinical response to doxycycline should be monitored closely.
5. Phenytoin, Sodium Valproate, Valproic Acid: The effect of barbiturates on the metabolism of phenytoin appears to be variable. Some investigators report an accelerating effect, while others report no effect. Because the effect of barbiturates on the metabolism of phenytoin is not predictable, phenytoin and barbiturate blood levels should be monitored more frequently if these drugs are given concurrently. Sodium valproate and valproic acid appear to decrease barbiturate metabolism; therefore, barbiturate blood levels should be monitored and appropriate dosage adjustments made as indicated.
6. Central Nervous System Depressants: The concomitant use of other central nervous system depressants, including other sedatives or hypnotics, antihistamines, tranquilizers, or alcohol, may produce additive depressant effects.
7. Monoamine Oxidase Inhibitors (MAOI): MAOI prolong the effects of barbiturates probably because metabolism of the barbiturate is inhibited.
8. Estradiol, Estrone, Progesterone, and other Steroidal Hormones. Pretreatment with or concurrent administration of phenobarbital may decrease the effect of estradiol by increasing its metabolism. There have been reports of patients treated with antiepileptic drugs (e.g. phenobarbital) who become pregnant while taking oral contraceptives. An alternant contraceptive method might be suggested to women taking phenobarbital.
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| Toxicity |
Not Available |
| Organisms Affected |
Humans and other mammals |
| Chemical IUPAC Name |
5-ethyl-1-methyl-5-phenyl-hexahydropyrimidine-2,4,6-trione |
| Chemical Formula |
C13H14N2O3 |
| Molecular Weight |
246.262 g/mol |
| Smiles String |
CCC1(C(=O)NC(=O)N(C1=O)C)C2=CC=CC=C2 |
| Melting Point |
176 °C |
| Water Solubility |
Slightly soluble |
| State |
Solid |
| LogP/Hphobicity |
1.916 |
| Isoelectric Point |
7.8 |
| Biotransformation |
Hepatic, primarily by the hepatic microsomal enzyme system. About 75% of a single oral dose of mephobarbital is metabolized to phenobarbital in 24 hours. |
| Half Life |
34 (range 11Ð67) hours |
| Protein Binding [%] |
70-76% |
| RxList Link |
RXlist |
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| Drug Reference |
http://www.rxlist.com/cgi/generic2/mephobarbital.htm |
| Drug Type |
Approved Drug |
| Accession No |
APRD00047 |
| CAS Registry Number |
115-38-8 |
| KEGG Compound ID |
Not Available |
| PubChem ID |
SID:151408 |
| PharmGKB ID |
Not Available |
| SwissProt ID |
Not Available |
| GenBank ID |
Not Available |
| Drug ID Number [DIN] |
Not Available
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