A convulsant is a drug which induces convulsions and/or epileptic seizures, the opposite of an anticonvulsant. These drugs generally act as stimulants at low doses, but are not used for this purpose due to the risk of convulsions and consequent excitotoxicity. Most convulsants are antagonists (or inverse agonists) at either the GABA_A or glycine receptors, or ionotropic glutamate receptor agonists. Many other drugs may cause convulsions as a side effect at high doses (e.g. bupropion, tramadol, pethidine, dextropropoxyphene) but only drugs whose primary action is to cause convulsions are known as convulsants.

[edit] Uses

Some convulsants such as pentetrazol and flurothyl were previously used in shock therapy in psychiatric medicine, as an alternative to electroconvulsive therapy. Others such as strychnine and tetramethylenedisulfotetramine are used as poisons for exterminating pests. Bemegride and flumazenil are used to treat drug overdoses (of barbiturates and benzodiazepines respectively), but may cause convulsions if the dose is too high. Convulsants are also widely used in scientific research, for instance in the testing of new anticonvulsant drugs.

[edit] Examples

GABA_A receptor antagonists, inverse agonists or negative allosteric modulators

• Bemegride
• Bicuculline
• Cicutoxin
• DMCM
• FG-7142
• Fipronil
• Flumazenil
• Flurothyl
• Gabazine
• Oenanthotoxin
• Pentetrazol
• Picrotoxin
• Sarmazenil
• Securinine
• Tetramethylenedisulfotetramine
• Thujone

Glycine receptor antagonists

• Brucine
• Colubrine
• Diaboline
• Gelsemine
• Hyenandrine
• Strychnine
• Tutin

Ionotropic glutamate receptor agonists

• AMPA
• Domoic acid
• Kainic acid
• NMDA
• Quisqualic acid
• Tetrazolylglycine