Today my tutor explained to me why normally levodopa was prescribed together with carbidopa (Sinemet). The levodopa is prescribed for treatment of Parkinson’s disease which is due to low level of dopamine in the brain. Dopamine is responsible for movement or mobility.
Levodopa works by being converted to dopamine in the brain. However, before it is being converted to dopamine in the brain, it undergoes peripheral conversion to dopamine, thereby reducing the effectiveness of the drug while increasing the side effects such as nausea, vomiting and cardiovascular effects.
Therefore, carbidopa is prescribed in combination with the levodopa in order to prevent the levodopa being broken down before it reaches the brain. This then allows a lower dose of levodopa to be taken to avoid or minimize side effects such as nausea and vomiting.
At home I did extra study and found that the total daily dose of carbidopa should be a least 70mg. Lower dose of carbidopa may not achieve full inhibition of extracerebral dopa-decarboxylate.
I did the calculation for the hospital prescription for 3 months supplies. The following is the method I used to get to the quantities to be dispensed.
For codeine phosphate, since it is administered four times a day, hence, in a week, it is 28 tablets. Then 3 months is equivalent to 3 x 4 weeks = 12 weeks. Therefore, the total quantities to be dispensed for codeine phosphate is 12 x 28 tablets = 336 tablets.
Since the pack comes in size of 28 tablets per pack. Therefore, 12 packs of 28 tablets of codeine phosphate were dispensed.
For naproxen, twice a day administration in a week is equivalent to 14 tablets. Since the pack comes in 56-tab pack (14 x 4 weeks), therefore, 3 packs were dispensed.
For lansoprazole, once a day in a week is 7 capsules. The pack comes in 28-tab pack; therefore, 3 packs were dispensed.
I queried about chlorpromazine with my tutor and learned that chlorpromazine used as anti-depression is not very recommended. This is because there is possibility of developing adverse effects which can be irreversible.
Then we discussed more about antipsychotic drugs which some are used to treat schizophrenia. Opposite mechanism to Parkinson’s disease, schizophrenia is due to high level of dopamine or the brain is too sensitive to dopamine.
I learned that chlorpromazine associated with a wide range of side effects, e.g. extrapyramidal symptoms such as parkinsonian symptoms, dystonia, akathisia, and tardive dyskinesia. I did little research about the causes and found that dyskinesia might be due to long term treatment of L-Dopa for Parkinson’s disease besides high level of dopamine which causes involuntary movement impaired.
Then few days later, I was taught that procyclidine which is an antimuscarinic drug, is used to counter the side effects of chlorpromazine or antipsychotic drugs. From the BNF 53, procyclidine is used for Parkinsonism and drug-induced extrapyramidal symptoms, but not for tardive dyskinesia.
I was taught by my tutor about the use of tamoxifen in the treatment of breast cancer. Tamoxifen (oestrogen inhibitor) is used to block and stop oestrogen to cancer cell. This is because the certain breast cancer cells use the oestrogen to survive. Tamoxifen can be used in both pre- and postmenopausal women.
On the other hand, aromatase inhibitor, anastrozole is used in postmenopausal women only with breast cancer. It works by inhibiting the conversion of androgen to oestrogen. This is because androgen present in the women as well and may be converted to oestrogen.
At home, I did further study on the topic and learned that diethylstilbestrol is used to treat prostate cancer in men by suppressing the effect of testosterone, hence shrinking the tumour. It can be used to treat breast cancer in women as well but higher doses are needed.
Apart from that, I also learned that gonadorelin analogue is used to treat advanced breast cancer in premenopausal women and advanced prostate cancer in men. It is known that the gonadorelin analogue causes stimulation of luteinising hormone (LH) release in the first 1 – 2 weeks before it starts depress the LH the following weeks. Therefore, it is important to administer the patient with anti-androgen before starting gonadorelin analogue, approximately 3 weeks before.
Examples of gonadorelin analogues are buserelin, goserelin, or triptorelin.
Examples of anti-androgens are cyprotene acetate, flutamide, or bicalutamide.
Thiazide diuretics are classed as "moderately potent" diuretics. They are often used to treat high blood pressure, especially in older people. See Common diuretics.
A low dose of a thiazide diuretic (for example 2.5mg of bendroflumethiazide) is often the first thing your doctor will prescribe if you have a slightly high blood pressure. This can be taken on its own or in combination with another blood-pressure medicine such as an ACE inhibitor or beta-blocker. For more information please see the separate Bupa health factsheets, ACE inhibitors and Beta-blockers.
Loop diuretics
These medicines are named after the loop of Henlé, one of the tubes inside the kidney. Loop diuretics are powerful diuretics that are usually used for treating heart failure.
The main effect of loop diuretics is to make the kidneys re-absorb less salt and water, and so produce more urine. Removing the excess water gives the heart less pumping work to do and reduces any breathlessness or ankle swelling.
Potassium-sparing diuretics
These medicines are named after their action, which helps to prevent the removal of potassium from the body by diuretics. Potassium has many important roles in your body, including keeping your heart healthy and your blood pressure at a normal level.
Potassium-sparing diuretics are weak when used alone but are often given in combination with a thiazide diuretic to prevent low potassium levels in the body (hypokalaemia).
They work on the salt balance (the balance of sodium and potassium chloride) within the kidneys. They do this by increasing the amount of sodium that is lost from the body in the urine and reducing the amount of potassium lost in the urine. This helps to maintain the potassium levels in the body.
How do diuretics work?
Thiazides, loop diuretics and potassium-sparing diuretics all work on the kidneys.
The kidneys have a network of tubes that make urine by filtering the blood in two stages. In the first stage, the water, salt and the waste products such as urea are filtered out from the blood, leaving behind the red and white blood cells. But lots of nutrients and other essential substances also leave the blood at this stage.
In the second stage there is a backwards filter, where the kidneys re-absorb the nutrients and essential substances back into the blood. This leaves the waste products, plus some salt and water, in the kidneys. This waste leaves the kidneys as urine.
Heart failure makes the kidneys re-absorb more water and salt into the blood, and so produce less urine. This is the body's way of trying to compensate for the reduced pumping power of the heart, but it actually makes matters worse. There is a bigger volume of blood for the heart to pump, and so more work for it to do. Also the excess water in the blood tends to leak out into the lungs, which can lead to breathlessness. Heart failure can also make your ankles and feet swell up.
Diuretics reduce the amount of water and salt that is re-absorbed by your kidneys. So, more water and salt passes out with the waste products into your urine. This means that you make more urine. As a result of this loss of water from the blood, the overall volume of blood is reduced. This gives your heart less work to do and helps to reduce the pressure of blood in your arteries, which is what high blood pressure actually is. How to take a diuretic
Most diuretics come in the form of tablets (known as "water tablets"). It's best to take these in the morning or early afternoon so that the extra urine your kidneys produce doesn't interfere with your sleep. Diuretics also come as injections but most people only take water tablets.
Because loop diuretics can cause blood potassium levels to fall, your doctor may advise you to take a supplement of potassium. You can also help keep your potassium levels up by eating foods with a high potassium content. Bananas are a good source of potassium.
Side-effects
You may not notice any side-effects with a low dose of a thiazide diuretic. At higher doses, you may get an upset stomach or feel faint or dizzy when you stand up. This can be caused by low blood pressure.
The first time you take a loop diuretic you may need to pass a very large volume of urine and take regular trips to the toilet. Your doctor may advise you not to take this medicine in the evening, as it will increase the number of times you have to get up in the night to go to the toilet.
Loop diuretics can also make you feel dizzy, especially during the first few days of treatment. Other, less common, side-effects can include:
Breast cancer has become a normal phenomenon especially to old women. To put it simply, it has become one of the world top killers.
Breast cancer needs oestrogen (female hormone) to feed the cancer cells and grows.
In palliative treatment of breast cancer, tamoxifen (anti-oestrogen agent) is used to stopping the oestrogen to cancer cells. It is preferably to be used in postmenopausal women, and not postmenopausal women.
Meanwhile, prostate cancer which occurs only in men is dependent on testosterone hormone (male hormone).
Diethylstilbestrol is used to treat prostate cancer b y suppressing the effects of testosterone, thus shrinking the tumour. It can also be used to treat breast cancer but at higher dose.
It’s been long time since the last time I wrote here.
Today, one of the many things I learned from my tutor is about the use of diclofenac together with the misoprostol which come in same one product. This combination product is used to relieve pain and inflammation due to rheumatoid arthritis, osteoarthritis, and postoperative pain.
The main reason for this combination is because diclofenac which is Non-steroidal anti-inflammatory drug (NSAIDs) may irritate the lining of the stomach despite its therapeutic use as painkiller and anti-inflammatory agent.
Meanwhile, the misoprostol (prostaglandin analogue) helps to protect the stomach lining from the irritation effect of diclofenac.
There are different types of eye problems such as dry eyes, conjunctivitis and glaucoma. Different type of treatments is available for each eye syndromes.
There are different types of eye problems that can occur to anyone throughout his or her life. Some of them have potential harm to the sufferer while some are minor and do not really need any interventions.
(1)Conjunctivitis
One of the common eye problems is the conjunctivitis. It is associated with painful red eye. In conjunctivitis, the conjunctiva in the eye becomes inflamed due to infection allergy or irritation.
There are two possible infections either by bacteria or virus. The bacterial infection is associated with stickiness and reddening of the eyes but viral infection is associated with watery eyes. It rarely occurs at both eyes but if it does, this may suggest other cause such as presence of foreign body or other condition.
Symptoms
(1)Eye discomfort like burning gritty and minimal pain.
(2)Minimal photophobia.
(3)Eyelids stuck due to discharge after sleep.
(4)Blurring vision by discharge. This can be cleared by blinking.
Referral to doctor
(1)Moderate to severe pain.
(2)If the eye become too red. This may suggest serious secondary cause and investigation need to be done.
(3)Loss of visual acuity.
Serious causes of a red eye
(1)Acute glaucoma
a.Raised intraocular pressure with pain in the eye, headache, and blurring of vision.
Treatment
There is no serious reason to start a treatment for conjunctivitis as it is self-limiting and will resolve within 1-2 weeks.
Chloramphenicol eye drops is typically used in the management of conjunctivitis and is applied every 2 hours for the first 48 hours and then 4 hourly for 5 days before it is discarded.
Fusidic acid is an alternative to chloramphenicol in case the use of chloramphenicol is contraindicated. Fusidic acid is more suitable for pregnant women and it is usually used twice a day for seven days.
(2)Stye
Stye eye is associated with redness, tenderness and pain in the eye. It is very obvious to the sufferers as they can diagnose it by detection of a spot pimple present below the eyelid.
It is common to people of all ages and usually resolved spontaneously within few two to three days. Antibacterial ointment is usually recommended for treatment of stye.
People with diabetes mellitus are more prone to get stye eye and is triggered by stress. Women and men are equally affected by stye. It is also believed that style is more prevalence in people with high blood lipid as the blockage may occurs.
Symptoms
(1)Redness, tenderness and pain
(2)Usually affecting one eye
(3)If left untreated, swelling with followed up with discomfort when blinking eye.
(4)Watering of the eye.
(5)Photophobia
Treatments
(1)Anesthetic to relieve the pain due to the stye.
(2)Antibiotic ointment. This requires prescription from the doctor is not available OTC.
Advices
(1)Don’t wear contact lenses during the infection.
(2)Avoid eye makeup.
(3)Use warm clothes and gentle compress the eye for about 10 mintues. This is in order to rupture the blockage to facilitate drainage.
(4)Don’t touch eye and keep the eye tools clean.
(5)Don’t squeeze the stye as it may promote infection.
(6)No contact lenses when suffering from stye.
Referral
(1)Symptoms persist for several days without improvement despite efforts ease it.
(3)Dry eyes
Dry eye syndrome is very normal and is nothing to worry about. It is due to disorder of the tear film and causes excessive evaporation from the surface of the eyes.
Symptom of dry eyes will be exacerbated by dry air, wind, dust and smoke.
Symptoms
(1)Not red but irritated especially when close eyes tightly.
Treatments
Artificial tears (Hypromellose 0.3% eye drops) are the treatment of dry eyes. Beware of the preservatives such as benzalkonium hexachloride that may irritate eyes. If more than 6 applications per day are needed; it is recommend using preservatives free preparation.
An eye ointment with paraffin or paraffin plus lanolin is used to provide lubrication to the affected eyes. It is best applied at night especially bedtime because it may blur vision.
Advices
(1)Don’t wear contact lenses.
(4)Glaucoma
Glaucoma is a serious eye problem and need to be referred to the GP as soon as possible. It is due to increased in intraocular pressure that built up due to fluids within the eyes.
