All medicines have side effects, says Professor Rhiannon Braund, head of the University of Waikato\u2019s school of pharmacy and biomedical sciences.<\/p>\n
\u201cWhen you\u2019ve got a drug that acts in different parts of the body, it can have different reactions or different outcomes for people based on their physiology,\u201d she says.<\/p>\n
\u201cThat\u2019s why dosing is really important because we\u2019re all a little bit different. We\u2019ve got different little quirks about all of us.\u201d<\/p>\n
All medicines have data sheets listing the known side effects ranging from common to rare, according to clinical trials. But those clinical trials are conducted on a narrow representation of the wider population. <\/p>\n
\u201cThey don\u2019t usually have trials with women. The risk of hurting or damaging an unborn child when these drugs are being tested is too high,\u201d Braund explains.<\/p>\n
\u201cSo they\u2019re often on healthy males, and the side effects that are seen in the clinical trials [are in] that controlled environment. And so the side effects that we do see coming out afterwards are things that we couldn\u2019t have predicted or we don\u2019t know.\u201d<\/p>\n
Some of those effects are due to drug interactions, which can\u2019t always be predicted in a clinical trial. It\u2019s why Medsafe in New Zealand monitors medicines for side effects once they\u2019re publicly available.<\/p>\n
Prescribers are \u201chypervigilant\u201d when it comes to the possible side effects of newly available medicines, Braund says.<\/p>\n
\u201cNurses, doctors or pharmacists are always really mindful of talking to their patients about side effects when we don\u2019t really know a lot about the medicines.\u201d<\/p>\n
Wegovy is one of the GLP-1s now available for weight loss in New Zealand. Photo \/ Getty Images<\/p>\n
What GLP-1s are available in New Zealand?<\/p>\n
Semaglutide (Wegovy), dulaglutide (Trulicity) and liraglutide (Victoza, Saxenda) are available in New Zealand. Some are available on prescription for weight loss as well as for diabetes. Ozempic is another brand of semaglutide, which we don\u2019t have here. <\/p>\n
Pharmac has funded dulaglutide and liraglutide for type 2 diabetes, but not for weight loss \u2013 so those who are prescribed them for weight loss must pay for them.<\/p>\n
The data sheets for the GLP-1s available in New Zealand list both their potential positive and negative side effects \u2013 here Braund explains why they occur, what you need to know and when to be concerned.<\/p>\n
What are the positive side effects of these weight loss drugs?<\/p>\n
GLP-1s offer some health benefits that come about as a result of weight loss, as well as other unexpected positives<\/a>.<\/p>\n For many people, Braund notes, \u201cit\u2019s not just about physical weight \u2013 it\u2019s about the consequences of carrying a little bit too much weight. It does have all of these other knock-on effects.<\/p>\n \u201cCarrying a little bit more weight than we should does have problems for us around stroke and lots of other cardiovascular issues.\u201d<\/p>\n Reduce risk of heart attack, stroke<\/b><\/p>\n Obesity increases the risk of a heart attack by straining the heart to pump harder, among other things. By triggering rapid weight loss, GLP-1s can lower that risk, as well as that of stroke.<\/p>\n Reduce risk of fatty liver disease<\/b><\/p>\n They can also reduce your risk of fatty liver disease, which is caused by fat build up in your liver, and of lipid disorders \u2013 an unhealthy balance of the fats in your blood.<\/p>\n Lower blood pressure<\/b><\/p>\n GLP-1s can help lower blood pressure through weight loss as excess body fat makes the heart work harder. The drugs also help your kidneys get rid of more salt and improve blood vessel function. <\/p>\n Reduce risk of kidney disease, diabetes-related <\/b>nephropathy or kidney damage<\/b> <\/b><\/p>\n GLP-1s can slow the progress of kidney disease and lower risk of kidney failure, though experts say nutritional support is essential with this.<\/p>\n Reduce risk of seizures<\/b><\/p>\n Studies have suggested that GLP-1s can reduce the risk of seizures, though more research is needed. <\/p>\n Help with addiction<\/b><\/p>\n GLP-1s suppress the hunger hormone, so can help with food addiction. Following that logic, some researchers have suggested they could be used to curb other addictions, such as to alcohol or opioids.<\/p>\n Help with obstructive sleep apnoea<\/b><\/p>\n Even minor weight loss can make a difference to those with sleep apnoea, Braund says.<\/p>\n \u201cWhen you\u2019ve got sleep apnoea, you wake up more tired than when you went to bed.\u201d<\/p>\n Benefits for PCOS<\/b><\/p>\n GLP-1s may have benefits for people with PCOS (polycystic ovarian syndrome) by lowering insulin resistance and regulating hormones and ovulation.<\/p>\n Weight loss as a result of using GLP-1s could help \u201cthe body regulate all of those things a little bit better,\u201d Braund says.<\/p>\n For the same reason, they may improve fertility. That\u2019s partly because obesity can impact fertility in both men and women, so rapid weight loss can boost it. If you\u2019re on the contraceptive pill, GLP-1s can affect how well it works as it slows the absorption into your body.<\/p>\n It\u2019s unknown whether GLP-1s are safe to use in pregnancy. <\/p>\n What are the negative side effects?<\/p>\n Nausea, vomiting, diarrhoea, indigestion, constipation<\/b><\/p>\n GLP-1s commonly cause gastrointestinal symptoms, because they slow down the emptying of your stomach and affect the part of the brain that triggers vomiting.<\/p>\n \u201cMost of [those] are quite mild and they resolve quite quickly,\u201d Braund says.<\/p>\n \u201cYou can modify that by what we call dose titration, so lower dose, and then people get more used to it.\u201d<\/p>\n Bone fractures and muscle loss<\/b><\/p>\n Some research has suggested GLP-1s increase the risk of bone fractures due to a reduction in bone mineral density due to weight loss, while other studies have found no risk.<\/p>\n And according to research from Mass General Brigham (based at Massachusetts General Hospital) any form of weight loss can see people experience muscle loss – not just during the use of GLP-1 medication.<\/p>\n \u201cIn simple terms, when you lose weight, you are decreasing caloric intake in terms of proteins, carbohydrates, and fats,\u201d says Dr Caroline Apovian, one of the researchers. \u201cThe brain needs glucose. Fat by itself cannot be turned into glucose, and that is the major reason why muscle loss is inevitable when you decrease caloric intake.\u201d <\/p>\n Their research found combining a high protein diet with consistent exercise while on GLP-1s, has the greatest benefit in preserving bone and muscle mass, compared to either technique being used alone. <\/p>\n You need 0.8g-2.2g per kg of your body weight in protein each day \u2013 find out more about how to get it here<\/a>.<\/p>\n Headaches and dizziness<\/b><\/p>\n These commonly occur when starting GLP-1s as the body adjusts to the drug and usually ease with time.<\/p>\n Mild tachycardia (increased heart rate)<\/b><\/p>\n Another common side effect that is usually harmless. Staying active and limiting alcohol and caffeine can help. Monitor if you have an existing heart condition and if you experience palpitations or chest pain, tell your doctor.<\/p>\n Upper respiratory tract infection<\/b><\/p>\n This is listed as a common side effect of some GLP-1s available in New Zealand. It hasn\u2019t been proven that GLP-1s cause these infections, but they can be associated with the symptoms.<\/p>\n GLP-1s can cause acid reflux, which can irritate your throat. They also stimulate your vagus nerve, which helps control your immune system as well as your digestion and heart rate. <\/p>\n This side effect also usually subsides over time.<\/p>\n Hair loss <\/b><\/p>\n Hair loss is listed among the common side effects of Wegovy. But as Braund notes, \u201cIt\u2019s hard to know [if this] is actually from the drug [or if this] just happens at the same time.\u201d<\/p>\n That\u2019s why when medical assessors look at reported side effects, they consider the \u201ctemporal relationship\u201d \u2013 when the effect occurred in relation to when the drug was taken. <\/p>\n \u201cDid that happen in a logical time-wise fashion?\u201d<\/p>\n Injection site reactions<\/b><\/p>\n Some people may find their skin reacts at the site where they\u2019re injecting themselves, whether they\u2019re on a daily or weekly dose.<\/p>\n \u201cThey\u2019re not painful injections, but we would encourage people to rotate where they do them,\u201d Braund says.<\/p>\n In the future, an oral version may be available in New Zealand, which would remove this risk.<\/p>\n Hypoglycaemia<\/b><\/p>\n Low blood sugar is a common side effect in people on GLP-1s who also have type 2 diabetes.<\/p>\n Gastroparesis\/stomach paralysis or delayed gastric emptying<\/b><\/p>\n GLP-1s slow down your digestion, which in some people can become excessive and leave the stomach muscles unable to work properly \u2013 though this is rare, according to the drugs\u2019 data sheets.<\/p>\n Gallstones or gall bladder inflammation<\/b><\/p>\n GLP-1s also slow down the gall bladder\u2019s emptying of bile, and may be associated with an increased risk of gallstones, another rare side effect.<\/p>\n Pancreatitis<\/b><\/p>\n A rare side effect of GLP-1s is pancreatitis, which is inflammation of the pancreas causing severe pain in the upper abdomen, nausea and vomiting. <\/p>\n Recent studies show the risk is minimal, though it\u2019s important to monitor the above symptoms and see your GP if you have concerns.<\/p>\n Potential increased risk of diabetic retinopathy, NAION<\/b><\/p>\n Professor Rhiannon Braund is the head of the University of Waikato\u2019s school of pharmacy and biomedical sciences. Photo \/ Supplied<\/p>\n