Monday, June 20, 2011

Effects of Lithium toxicity

Lithium is a medication prescribed for bipolar affective disorder and resistant depression. It has one of the simplest structure (in ionized form an atom), but has quite complex mechanism of action. In addition, it is also a toxic metal to the human body. But toxicity occurs when the blood lithium levels reach a critical level.
Usually Lithium should be taken in higher dose for some time to get lithium toxicity. It is unlikely to get lithium toxicity when single large dose of lithium is taken.

However, critical level that is needed to produce toxicity and the level that is needed to achieve symptom control is within a narrow margin. Therefore, it is important to take the drug as prescribed, take adequate amounts of water and do regular lithium levels in the blood (at least every six months). In addition, it is important to know the early features of lithium toxicity and get medical attention before full blown toxicity sets in.

What are the important lithium levels?
Lithium levels should be monitored after 12 hours of last dose. If the patient is on twice daily dosing then blood should be taken just before the morning dose of the day (Lithium is usually prescribed once or twice a day). Blood should be collected to a plain bottle and carried to the laboratory.

Lithium normal therapeutic range
0.6 - 1.2 mmol/l

Early toxicity
> 1.5mmol/l

Life threatening toxicity
>2.0 mmol/l

How to prevent lithium toxicity?

Lithium levels should be tested at least every six monthly in a patient with stabilized regimen. In addition, patients should not take NSAID pain killers, ACE inhibitors, and Diuretics without expert advice. It is important to note that they should not take over the counter NSAID pain killers such as Aspirin and Motrin.

Effects of lithium on organs

1. Kidney failure – 1% of patients develop irreversible kidney damage on long term use (after 10 years of treatment).
a. Around 10% develop structural kidney changes
2. Hypothyroidism: Around 5 -35% develops reversible thyroid gland failure. But treatment with thyroxin can alleviate the symptoms.
3. Effects on the developing baby: Lithium is known to cause heart anomalies in the newborn, if taken during pregnancy. There is 400 fold rises in the incidence of Ebstein anomaly of the heart.

What are the symptoms of Lithium Toxicity?

Early signs

1. Marked tremors,
2. Anorexia, Nausea/Vomiting,
3. Diarrhea, and lethargy

Late signs

1. Restlessness
2. Muscle fasciculation’s/jerks
3. Abnormal movements
4. Severe drowsiness
5. Confusion
6. Reduced blood pressure
7. Heart rhythm abnormalities
8. Fits

What are side effects of Lithium therapy?

Side effects are different from toxic effects. It is because side effects can occur within lithium normal dosage range. They are not usually dangerous.

Warning and disclaimer
This articles is for the information only. You should not take or discontinue lithium without your doctors advice.

New Oxford textbook psychiatry

Sunday, June 19, 2011

How chronic insomnia is treated with sedative hypnotics–New guidelines

According to the stahl’s essentials of psychopharmacology 3rd edition, There is a place for long term use of sedative hypnotics in chronic insomnia. Sedative hypnotic is a drug that causes depression of central nervous system activity which causes sleep.

The old guidelines recommend short term use of sedative hypnotics, improve sleep hygiene and treat the underlying cause for insomnia. It does not appreciate chronic insomnia as a disease entity on its own.

In addition, most of the older sedative hypnotics such as benzodiazepines (Vallium, Dalmane) and barbiturates are comparatively long acting. These long acting compounds tend to cause sleepiness in the following day and falls/hip fractures in the elderly. In addition, they tend to cause withdrawal symptoms and dependence.

New thinking on insomnia and sedative hypnotic use

Now most experts think chronic insomnia is a disorder by itself and there is a need for long term treatment. In addition, hypnotics such as Zaleplon, Zolpidem and Zopiclone extremely short acting. Therefore they do not show any sleepiness in the following day.

In addition, long term studies conducted on eszopiclone shows little or no tolerance (need to take increasing amount of drug to get the same effect) and withdrawal symptoms (Stahl, 3rd).

Following hypnotics have shown marked promise and have no restrictions in the long term use. However, some of them may cause sleepiness in the next day morning.

1. Zolpidem CR (Ambien continuous release)
2. Trazadone (Desyrel)
3. Quatiapine (Seroquel)

This drug related blog post is for information only. YOU MUST CONSULT YOUR DOCTOR BEFORE TAKING THESE DRUGS.

Essential psychopharmacology Stahl, 3rd edition

Saturday, June 18, 2011

Improving Memory – 3 Tips to Remember Things Better

According to the Atkinson and Hilgard's  Introduction to psychology Human memory can be divided into sensory store, short term store and long term store. To memorize things you need to optimize the long term memory store. Short term store or working memory is used primarily to maintain attention and concentration. Sensory store is a large repository of crude data and it cannot be used to improve memory.

Understand the items you are trying to memorize. Understanding the stuff automatically create meaningful connections (Automatic backlinks Smile). These connections can help us to retrieve stuff.
Organize stuff into categories before memorizing. Most common cause for memory failure is retrieval failure or we forget the retrieval cues. By categorizing stuff before memorizing it will be easier for us to get retrieval cues.

If you cannot remember what you have memorize. Then try to go mentally to the place you have memorize that fact. For an example if you want to remember a friends name in your high school then go mentally to your high school or try to remember buildings, teachers, events you have attended in your high school then you will remember his/her name.
These tips are more explained in the following post
1. How memory works - What are memory stores and how to improve our memory

Monday, June 6, 2011

Side effects and problems associated with electroconvulsive therapy (ECT)

ECT is artificial induction of fits (seizure) by sending an electric current through the brain. It is useful therapy for psychiatric disorders such as major depression, bipolar mania, bipolar depression and psychosis associated with child birth. In addition, it is used in patients with schizophrenia who have strong suicidal or homicidal ideas and psychotic patients who are not taking meals/water.

The main advantage of ECT over medications is its ability to give a quick response. Medications usually take at least two weeks to act. Therefore ECT would be one of the options when quick response is needed.
Patient receiving ECT
Problems and side effects associated with ECT

1. Problems of general anesthesia: - ECT is given under general anesthesia. Therefore, all the problems associated with general anesthesia can occur. They include allergic reactions, difficulty in getting up from anesthesia, post anesthesia muscle pain and stuff in the stomach going into the lungs (aspiration).

2. Memory loss: - ECT is associated with memory loss for certain events. This memory loss is usually irreversible. Level of memory loss is directly proportionate to the amount of electric current or the dose.

3. Possibility of aggravating problems inside the head: - If the patient has a defect in blood vessels inside the brain, there is a possibility of that being ruptured.

4. Possibility of getting uncontrollable fits or status epilepticus: - If the patient has a past history of epilepsy then there is a chance of getting a seizure that cannot be controlled. However, since the patient is anesthetized and an anesthetist is around this problem can usually be sought out. But the patient can get secondary seizure when he was in the ward.

Further reading

1. Use, preperation and side effects of ECT

Patient is Given ECT after general anesthesia

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