Anticoagulants
Prescribed to 11 million people in England in 2013, warfarin helps stop blood from clotting. It is recommended for conditions in which dangerous clots can occur, including atrial fibrillation (an irregular heartbeat), deep-vein thrombosis and heart attack.
There is a small risk of internal bleeding and excessive bleeding from cuts, and side effects include nausea and diarrhoea. Those taking it must have the dose checked frequently, usually once or twice a week.
Recently, alternatives that don鈥檛 require monitoring have been approved for atrial fibrillation. However, these are expensive, and don鈥檛 have such a long safety record. If warfarin causes a bleeding episode, it can be stopped with vitamin K; for newer anticoagulants there is no antidote.
Advertisement
ACE inhibitors
First isolated from the venom of a Brazilian snake, which causes a drop in blood pressure making a bitten animal black out, ACE inhibitors are routinely given to people with high blood pressure, also known as hypertension, to prevent stroke, heart attack and kidney failure.
Many people with mild hypertension also take this medication. Doctors are divided. Some believe that the lower your blood pressure is, the better, but research last year found that .
The US spends $32聽billion every year treating high blood pressure 鈥� 1 per cent of its annual healthcare costs. Critics say those with borderline readings should make lifestyle changes before starting on medication.
Polypills
Heart attack and stroke survivors are often prescribed a cocktail of drugs to prevent another event, and the mix of pills mean many struggle to stick to their regime. Polypills combine common drugs, such as a statin, ACE inhibitor and anti-platelet drug, in one daily tablet.
A study last year found that people taking polypills had a better adherence rate than those on separate drugs. One is already licensed for use in 11聽countries including Spain, Sweden and Mexico.
Polypills are currently considered suitable only for people who have already had a heart attack or stroke, but not as a preventive measure. Some doctors think we need more evidence that polypills are as effective as their individual parts.
Antidepressants
Antidepressants are big business: are estimated to be taking them. That doesn鈥檛 necessarily mean depression is on the rise 鈥� they are also given for mental health conditions such as anxiety, eating disorders and post-traumatic stress disorder, and a significant proportion of prescriptions are now for physical problems.
Antidepressants have become a mainstay in the treatment of conditions that involve long-term pain, and can help with migraine and arthritis, bedwetting in children, and even premature ejaculation.
Side effects range from sleeping problems to indigestion and erectile dysfunction. Long-term use has been linked to a raised risk of type聽2 diabetes, possibly because some drugs can lead to weight gain, and children born to women who took antidepressants during pregnancy are more likely to have birth defects.
Neuroenhancers
Originally licensed for conditions such as attention-deficit disorder, sleep apnoea and narcolepsy, there is now tentative evidence to suggest that drugs such as Ritalin (methylphenidate) and modafinil might help treat depression, Parkinson鈥檚 and multiple sclerosis. And healthy people are using them for their effects on memory, focus and wakefulness.
One UK survey of 2000 students at 41 universities found that 1 in 5 had used modafinil. Prescriptions have increased tenfold in the US, with . It鈥檚 not clear how modafinil works, but it is thought to act on several neurotransmitters. Modafinil has side effects such as reduced appetite and insomnia, and the long-term effects of taking it are still unclear.
Metformin
The UK National Health Service now spends more on diabetes drugs than any other prescribed medication. In England, 44.6聽million prescriptions are written every year, at a cost of almost 拢800聽million. Metformin is the most common medication for type聽2 diabetes, and makes the body more responsive to insulin while stopping the liver from making glucose, so that blood sugar levels are better controlled.
It is also given to women with polycystic ovary syndrome, because this condition causes insulin resistance. Metformin may help with the associated weight gain and fertility problems.
The drug has other potential benefits. A study last year found that people taking metformin lived longer than people who weren鈥檛 taking it and didn鈥檛 have diabetes.
The American Diabetes Association has called for people with 鈥減re-diabetes鈥� 鈥� where blood sugar levels are high but not high enough to fall into the diabetes category 鈥� to be considered for metformin therapy, to slow or prevent the development of the disease.
This strategy remains controversial. Analysis published in the BMJ last year said and found no evidence of benefit from starting metformin early.
The drug is not without side effects: 1 in 10 people taking it experiences gastrointestinal problems such as nausea, vomiting, diarrhoea or stomach pain.
Thyroid drugs
Around 5 per cent of people in the US are thought to have an underactive thyroid or hypothyroidism. The standard treatment is daily tablets of levothyroxine, to replenish levels of the thyroid hormone, thyroxine. Often this is a lifelong medication regimen.
Levothyroxine controls the condition effectively, as long as it is given in the right dose 鈥� users must have regular tests. If the dose is too high, people can get the symptoms of overactive thyroid, including chest pain, sweating, headaches and vomiting. Long-term over-treatment with levothyroxine is associated with atrial fibrillation and bone thinning.
There is debate over the threshold at which levothyroxine should be prescribed 鈥� some doctors believe it is appropriate if patients鈥� thyroid hormone levels are normal but their levels of thyroid stimulating hormone are raised, which can be a precursor to full-blown hypothyroidism.
Read more: 鈥�Our daily pills: What everyday drugs are really doing to you鈥�
