Lamotrigine is a fairly new drug, and is used for both partial complex seizures and generalized seizures. Its side-effects are generally mild. Its main advantage over other anti-convulsants is that it does not produce the same ‘slowing-down’ effect on thinking (though a few people do find that high doses of the drug have a sedative effect). In fact, for most people it is an alerting drug – some say it makes them feel as if they have had ten cups of coffee. However, if the dose is reduced a little, this feeling usually passes off. Some people have reported that lamotrigine increases sexual interest. This would be good news, but so far trials of the drug have not confirmed it.
Many people develop a rash when they first start to take lamotrigine, and the drug has to be withdrawn. This is a pity because it is a good drug, and the problem can usually be avoided if the drug is given in a low dose (25mg) for at least the first two weeks. If your doctor starts you on a higher dose it would be worth drawing this fact to his attention.
Possible side-effects
Rash
Hyper-alertness Toxic side-effects
(These indicate that the dose you are taking is too high.) Poor balance, double vision, tremor and, in high doses, tiredness.
BENZODIAZEPINES
The benzodiazepines — Diazepam (Valium), Clobazam (Frisium) and Clomazepam (Rivotril) – are a group of drugs which reduce the excitability of the brain by mimicking the effect of the inhibitory brain chemical GABA.
DIAZEPAM (VALIUM)
Diazepam is a benzodiazepine whose main use is to terminate status epilepticus or febrile convulsions. It is usually given intravenously, either by your doctor or in a hospital casualty department. The main disadvantage of intravenous diazepam is that it can suppress your ability to breathe. If this happens you will have to be taken to the intensive-care unit and your breathing watched and if necessary regulated by the use of a ventilator. Although such a side-effect is unlikely, it happens sufficiently often for doctors to be very aware of the possibility.
A safer way of giving diazepam as an emergency treatment for people who have serial seizures — that is, attacks which follow one after the other — or status epilepticus, or children with prolonged febrile convulsions, is in the form of diazepam suppositories (Stesolid). These are simple, effective and safe to give; they are placed in the rectum with an applicator. If someone in a family has frequent seizures their doctor may give them a supply of these suppositories so that they are on hand for emergency use.
A recent court case in Australia shows what a useful treatment this is felt to be. Stesolids are not licensed in Australia, although they are available. A physician who was treating patients in the outback was held to be at fault for not prescribing Stesolids for their emergency treatment, even though the drug was not licensed.
CLONAZEPAM (RIVOTRIL)
Clonazepam is also one of the benzodiazepine group of drugs, which are often used as tranquilizers. Its main value is its ability to control myoclonic seizures. It is also sometimes used as an alternative to Valium to control status epilepticus. It is usually given once daily (at night) although it is sometimes given twice a day, and its main drawback is that it has a strong sedative effect and causes drowsiness. Clonazepam will not be prescribed if your work requires you to be vigilant and alert. It may also cause personality changes, and these can, in my experience, be quite severe. One patient of mine changed from being a normal, affectionate teenager to an aggressive, rebellious tearaway; another attempted suicide soon after starting taking the drug. It is worth bearing this in mind if you notice that someone in your family who is taking the drug seems to be showing some personality change. See your doctor immediately because they will probably want to withdraw the drug straight away.
Another disadvantage of clonazepam, and of clobazam (a similar drug, see below) is that in some people tolerance develops fairly quickly, usually after three to six months. The drug then no longer has as great an effect. When tolerance has developed you will have to stop taking the drug for a while. However, even after a ‘drug holiday’ you may never regain the same response to the drug. With both clonazepam and clobazam you may get withdrawal effects when you stop taking it. These are the opposite of the tranquilizing effects; you may feel on edge all the time, anxious and ‘twitchy’, your skin my feel supersensitive and you will be more sensitive to noise. These effects may last for one to three weeks.
When to avoid
Clonazepam should not be taken with alcohol, during pregnancy or if you are breast-feeding. If you are taking this drug and thinking of becoming pregnant you should talk to your doctor, because there is now evidence that clonazepam may lead to an unusually high percentage of fetal abnormalities. If you find that you are pregnant while taking clonazepam it is important to see your doctor immediately and discuss the implications with them. You will need to decide whether or not you wish to continue with the pregnancy .
CLOBAZAM (FRISIUM)
Clobazam, like clonazepam, is a benzodiazepine, but it seldom causes personality change and has a less marked sedative action than clonazepam. It is used to control both partial and generalized seizures, and is sometimes given as a supplementary drug to women who have catamenial epilepsy. Its main success is in the reduction of partial complex seizures, and it has become very popular for treating these. Clobazam must be taken three times a day, and its main side-effect (seen mainly in large doses) is tiredness. Tolerance to the drug may also develop, with withdrawal effects when it is then stopped.
When to avoid
Clobazam should not be taken during pregnancy or if you are breast-feeding, and it should not be taken with alcohol.
ACETAZOLAMINE (DIAMOX)
Acetazolamine is sometimes given as a supplementary drug to women who have catamenial epilepsy (see p. 189). It is also used as a ‘Third Line’ drug, to be given to people who have clusters of seizures at the time of each cluster. Tolerance to the drug develops after some time. Acetazolamine is a diuretic (causes increased excretion of water) and so anyone who takes it for any length of time needs to have regular blood tests to make sure that their body chemistry is not being thrown out of balance by this loss of water. Acetazolamine is thought to work by making the cells more ‘acid’ but this has not yet been convincingly proved.
PHENOBARBITONE (LUMINAL)
Phenobarbitone is one of the oldest, really effective anticonvulsant drugs, and in many parts of the world is still the most widely-used treatment for epilepsy. It has several advantages: it is safe, for example, is as good as carbamazepine, phenytoin or valproate in controlling generalized tonic clonic seizures and partial seizures, and is the cheapest of all the anticonvulsants. Because it has a long half-life it also need only be given once a day. However, although it rarely produces serious side-effects, it is a strong sedative and can have a marked effect on mental processes. Some people are particularly sensitive to phenobarbitone and become mentally dull, drowsy and lethargic. If it is given to young children it can have the opposite effect, making them overactive and badly behaved. These effects mean that phenobarbitone is now rarely used if other drugs are available.
PRIMIDONE (MYSOLINE)
Primidone is an interesting drug. It is a weak anticonvulsant in its own right, and its major anticonvulsant action comes from the metabolism of primidone into phenobarbitone. It thus suffers from all the advantages and disadvantages of phenobarbitone. Because primidone has this dual anticonvulsant effect it is now generally agreed that there is little point in giving phenobarbitone, when by giving primidone you are giving two anticonvulsants instead of one. Thus, if cost is not an important issue, primidone (which is slightly more expensive) is probably the drug of choice where phenobarbitone would have been used. A few people, however, are sensitive to primidone but not to phenobarbitone.
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19Mar
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