Rybelsus (semaglutide) is an oral GLP-1 receptor agonist used to treat type 2 diabetes in the UK. Whilst dizziness is not listed as a common side effect in the Summary of Product Characteristics, some patients do experience it during treatment. This symptom often arises indirectly—through low blood glucose, dehydration from gastrointestinal effects, or postural blood pressure changes—rather than as a direct drug reaction. Understanding why dizziness may occur and how to manage it effectively allows most patients to continue benefiting from improved glycaemic control. This article explores the causes, management strategies, and when to seek medical advice.

Can Rybelsus Cause Dizziness?

Rybelsus (semaglutide) is an oral glucagon-like peptide-1 (GLP-1) receptor agonist licensed in the UK for the treatment of type 2 diabetes mellitus. Dizziness is not listed as a common adverse reaction in the UK Summary of Product Characteristics (SmPC); when it occurs, it is often secondary to other factors related to the medication's effects or individual patient circumstances.

The most frequently reported side effects of Rybelsus include gastrointestinal symptoms such as nausea, vomiting, diarrhoea, and abdominal discomfort. While dizziness is not prominently featured in clinical trial data, some patients do report experiencing it during treatment.

It is important to distinguish between dizziness as a direct drug effect and dizziness arising from related metabolic changes. For instance, improved glycaemic control may lead to lower blood glucose levels than a patient is accustomed to, potentially causing light-headedness. Similarly, gastrointestinal side effects—particularly nausea and reduced appetite—can lead to inadequate fluid or food intake, contributing to feelings of dizziness or faintness. In some cases, dehydration from these effects may have implications for kidney function.

Patients who experience dizziness whilst taking Rybelsus should not immediately discontinue the medication without medical guidance. Understanding the potential underlying causes and implementing appropriate management strategies can often resolve or significantly reduce symptoms, allowing patients to continue benefiting from effective diabetes management.

Why Dizziness May Occur with Rybelsus

Understanding why dizziness might occur with Rybelsus requires consideration of the medication's mechanism of action and its broader metabolic effects. Semaglutide works by mimicking the action of endogenous GLP-1, enhancing glucose-dependent insulin secretion, suppressing inappropriate glucagon release, and slowing gastric emptying. These actions collectively improve glycaemic control but can also trigger secondary effects that may manifest as dizziness.

Hypoglycaemia represents one potential contributor, particularly when Rybelsus is used in combination with other glucose-lowering medications such as sulphonylureas or insulin. Whilst Rybelsus alone carries a low intrinsic risk of hypoglycaemia due to its glucose-dependent mechanism, the addition of other agents increases this risk. When used with sulphonylureas or insulin, doses of these medications may need reduction under clinical supervision. Low blood glucose can cause symptoms including dizziness, light-headedness, confusion, sweating, and tremor. Patients should be educated to recognise these symptoms and understand how to respond appropriately.

Dehydration and reduced oral intake commonly occur with GLP-1 receptor agonists due to their effects on appetite suppression and gastrointestinal motility. Nausea—one of the most frequent side effects—may discourage adequate fluid consumption. Delayed gastric emptying can create feelings of fullness or discomfort, further reducing food and fluid intake. Both dehydration and inadequate nutrition can precipitate orthostatic hypotension (a drop in blood pressure upon standing), which manifests as dizziness or light-headedness. Importantly, dehydration can also precipitate acute kidney injury in susceptible individuals, particularly if vomiting or diarrhoea is persistent.

Postural hypotension may also occur independently of dehydration, particularly in patients taking concurrent antihypertensive medications or those with autonomic neuropathy secondary to longstanding diabetes. The combination of improved glycaemic control, weight loss, and potential volume depletion can collectively influence blood pressure regulation, making some individuals more susceptible to dizziness when changing position.

Managing Dizziness While Taking Rybelsus

Effective management of dizziness whilst taking Rybelsus begins with identifying and addressing the underlying cause. Patients should maintain a symptom diary documenting when dizziness occurs, its severity, associated activities (such as standing quickly), and any concurrent symptoms like nausea or sweating. This information proves invaluable during clinical consultations.

Monitoring blood glucose levels regularly helps identify hypoglycaemia as a potential contributor. Patients experiencing dizziness should check their blood glucose when symptoms occur. If readings consistently fall below 4.0 mmol/L, medication adjustments may be necessary—particularly if taking Rybelsus alongside sulphonylureas or insulin. The prescriber may need to reduce doses of these concurrent medications to minimise hypoglycaemia risk whilst maintaining overall glycaemic targets.

Optimising hydration and nutrition represents a cornerstone of management. Patients should aim to:

• Maintain adequate fluid intake tailored to individual needs (typically aiming for pale yellow urine)

• Follow clinician advice if on fluid restriction due to heart failure or kidney disease

• Consume small, frequent meals rather than large portions to manage nausea whilst maintaining adequate nutrition

• Avoid prolonged fasting periods that might exacerbate light-headedness

• Limit caffeine and alcohol, both of which can contribute to dehydration

If vomiting or diarrhoea persist, or if urine output decreases, patients should seek medical review for possible dehydration and its impact on kidney function.

Postural strategies can significantly reduce orthostatic dizziness. Patients should be advised to:

• Rise slowly from sitting or lying positions, pausing briefly before standing fully

• Sit on the edge of the bed for a moment before standing in the morning

• Avoid sudden head movements or rapid position changes

• Consider compression stockings if orthostatic hypotension is confirmed by a healthcare professional

If gastrointestinal side effects contribute significantly to dizziness through reduced intake, symptomatic management with antiemetics (as advised by a healthcare professional) may provide relief. The dose escalation schedule for Rybelsus is designed to minimise gastrointestinal adverse effects; ensuring adherence to this gradual titration can reduce symptom severity.

Remember to take Rybelsus correctly—on an empty stomach with no more than 120ml of water, waiting at least 30 minutes before eating or taking other oral medicines, and swallowing the tablet whole—as this optimises absorption and may influence tolerability.

When to Seek Medical Advice About Dizziness

Whilst mild, transient dizziness may resolve with simple management strategies, certain presentations warrant prompt medical evaluation. Patients should contact their GP or diabetes specialist nurse if dizziness is:

• Severe or persistent, significantly impacting daily activities or quality of life

• Associated with recurrent hypoglycaemia, particularly readings below 4.0 mmol/L or readings below 3.0 mmol/L (level 2 hypoglycaemia) or episodes requiring assistance from others

• Accompanied by other concerning symptoms such as chest pain, palpitations, severe headache, visual disturbances, slurred speech, or weakness

• Resulting in falls or near-falls, which pose injury risk, especially in older adults or those with reduced mobility

Immediate medical attention (via 999 or attendance at A&E) is required if dizziness occurs alongside:

• Signs of severe hypoglycaemia with confusion, loss of consciousness, or seizure activity

• Symptoms suggesting cardiovascular events (severe chest pain, breathlessness, or syncope)

• Neurological symptoms that might indicate stroke (facial drooping, arm weakness, speech difficulties - remember the FAST acronym)

• Severe dehydration with inability to retain fluids, reduced urine output, or altered consciousness

For urgent but non-life-threatening concerns when unsure what to do, NHS 111 can provide appropriate clinical advice.

Patients should also arrange a routine review with their diabetes care team if dizziness develops after starting Rybelsus or following dose increases. The healthcare professional can assess blood pressure (including postural measurements), review concurrent medications, evaluate glycaemic control patterns, and consider whether dose adjustment or additional investigations are warranted.

NICE guidance on type 2 diabetes management emphasises individualised treatment approaches and regular monitoring of both efficacy and tolerability. If dizziness proves intolerable despite management strategies, alternative glucose-lowering therapies should be considered. The decision to continue, adjust, or discontinue Rybelsus should always be made collaboratively between patient and prescriber, weighing the benefits of improved glycaemic control against the impact of adverse effects on quality of life.

Other Common Side Effects of Rybelsus

Beyond dizziness, patients taking Rybelsus should be aware of the medication's established adverse effect profile. Understanding these potential side effects enables informed decision-making and appropriate symptom management.

Gastrointestinal effects represent the most frequently reported adverse reactions, occurring in a substantial proportion of patients, particularly during treatment initiation and dose escalation:

• Nausea (very common, affecting more than 1 in 10 people) typically peaks during the first few weeks and often diminishes with continued treatment

• Diarrhoea (very common, affecting more than 1 in 10 people)

• Vomiting (common, affecting up to 1 in 10 people)

• Abdominal pain, constipation, and dyspepsia occur with variable frequency

• Reduced appetite is an expected pharmacological effect contributing to weight loss but may occasionally be excessive

These gastrointestinal symptoms usually improve over time as the body adjusts to the medication. Taking Rybelsus correctly—on an empty stomach with no more than 120ml of water, waiting at least 30 minutes before eating—optimises absorption and may influence tolerability.

Hypoglycaemia risk varies depending on concurrent diabetes medications. When Rybelsus is used as monotherapy or with metformin, hypoglycaemia risk remains low. However, combination with sulphonylureas or insulin substantially increases this risk, necessitating dose adjustments of these agents and patient education on recognition and management of low blood glucose.

Other notable adverse effects include:

• Fatigue (common), which may relate to dietary changes, improved metabolic control, or medication effects

• Gallbladder disorders including cholelithiasis and cholecystitis (uncommon but important)

• Pancreatitis (rare but serious)—patients should seek immediate medical attention for severe, persistent abdominal pain

• Diabetic retinopathy complications—patients with pre-existing retinopathy and rapid improvement in blood glucose control may be at increased risk; ophthalmic monitoring is advised, and patients should report any new visual symptoms

• Acute kidney injury risk from dehydration—particularly if unable to maintain fluid intake or experiencing persistent vomiting or diarrhoea

Thyroid considerations: In rodent studies, GLP-1 receptor agonists caused thyroid C-cell tumours. The relevance to humans is unknown, and this is not a contraindication in the UK SmPC for Rybelsus.

The MHRA continues post-marketing surveillance of semaglutide. Healthcare professionals and patients can report suspected adverse reactions via the Yellow Card Scheme (yellowcard.mhra.gov.uk), contributing to ongoing safety monitoring and ensuring that emerging safety signals are identified and addressed promptly.

Frequently Asked Questions