Anti-Epileptic Drugs

Thanks to molecular pharmacology for explaining this. Ah, you have to know how i love pharmacology...the lessons and the lecturer (hahaha). Basic pharmacology taught me about many types of drugs and their names too...molecular biology explain its mechanism of action in detail, in molecular detail. Yeah it can be complicated sometimes, but i think it's kind of fun.

I want to write a brief review about some of anti-epileptic drugs' mechanism. My favorite lecturer explained a few types of anti-epileptic drugs. Here they are (caution: may be very boring, but who cares, it is for my archieve):

#Phenytoin and Carbamazepin
These drugs prevents seizures by prolongs (and stabilizes) the inactivation time of sodium channels. In an epilepsy sufferer, the impulse in their nerve cells travel so fast and uncontrollable, causing a sudden, involuntary, and uncontrollable body and extremities movement (called grand-mal seizures). Sodium channels have an important role in this process; the traveling of impulse in nerve cells depends on how fast the propagation happens. Propagation happens when a sodium channel opens (activation), letting a sodium (Na+) ion enters the nerve cells and causing depolarization (reducing of electric potential/voltage between intracellular and extracellular milieu). This depolarization causing the next sodium channels to open, letting another sodium ion in and causing depolarization of that channel. Again, this depolarization open the next sodium channel to open. This event happens simultaneously until the impulse reaches the nerve cell ending. I imagine propagation as impulse running from channel to channel from axon to nerve cell ending.
Prolonged inactivation by those drugs causing the inhibition of impulse to travels, so they prevent seizures.

#Etosuksimid
Phenytoin and Carbamazepin, as told above, are used to treat grand-mal epilepsy (seizures of all parts of the sufferer's body). Beside grand-mal epilepsy there is another type of epilepsy, petit-mal epilepsy. In this epilepsy, the sufferer does not experience seizures. Instead, they are unconsious for a brief period of time. This may be accompanied by steady facial expressions and eyes staring blankly. People around them, or maybe themselves, may be unaware of this attack. Based on articles i read, 75% of petit-mal sufferers will experience grand-mal seizures later in their life :(
Petit-mal epilepsy's mechanism of occurance involves T-type (tiny/transient type) calcium channel. This type of calcium channels is an ion channel that can be activated by minor depolarization (slight reduction of electric potensial/voltage between intracellular and extracellular milleu). When it is activated, it opens and a calcium ion (Ca++) from extracellular milleu goes inside. Etosuksimid inhibits this channel to be open, thus prevents petit-mal attack.

Okay...those are from my lecturer. Then i searched in internet about valproic acid. Here it is:

# Valproic Acid
I am fond of this drug. Why? Because later i knew how great it really is. Valproic acid is able to prolongs and stabilizes the sodium channels (like phenytoin and carbamazepin). It is able to inhibits the opening of T-type calcium channels (like etosuksimid). Therefore, valproic acid can prevent both grand-mal and petit-mal seizures. It's also inhibits metabolism (transamination) of GABA by inhibits GABA transaminase enzyme. GABA is known for its effect on inactivating nerve cells. So, if we inhibits GABA metabolism, there will be more active GABA, causing greater nerve cells inactivation (good way for preventing seizures). To make it sounds greater, it also shows transquillizing effect like lithium. It is also now being investigated as a potent medication for HIV, lupus and cancer (because it inhibits Histone-Diacetylase enzyme). W.O.W :D
What's more? Valproic acid has minimum sedative properties and geberally has no intolerable side effects (but using this medication on patient with hepatic dysfunction is not recommended). I thing it will be cool to my industry to synthesize this drug so there will be more epilepsy sufferer saved, hehehe :P

But, what's bad about those drugs? They are all TERATOGENIC. Yeah, i know there is no such thing like 100% safe drug. Every drug (and food) has its own side effect. Just like Paracelcus said "Poison is in everything, and no thing is without poison. The dosage makes it either a poison or a remedy"