Individuals taking venlafaxine are being urged to be vigilant for a range of symptoms and side effects, prompting them to seek advice from 111 or consult their GP if needed.

Venlafaxine is a commonly prescribed SNRI, or serotonin and noradrenaline reuptake inhibitor. It’s primarily used for treating depression, but it also finds application in managing anxiety and panic disorders.

Typically available in tablet or capsule form, venlafaxine works by increasing the levels of serotonin and noradrenaline in the brain, which can lead to improved mood and emotional well-being.

Although NHS guidelines suggest that venlafaxine boasts fewer side effects compared to older antidepressants, this does not mean it is completely free from adverse effects.

Generally, it takes about four to six weeks for venlafaxine to reach its full potential in terms of effectiveness, though many patients report feeling better within the first one to two weeks of use.

According to the NHS, common side effects associated with venlafaxine include sweating, nausea, dry mouth, and headaches. These are typically mild and tend to diminish after a few weeks of treatment.

However, some other side effects could be deemed more serious and might warrant a call to 111 or see a GP. These severe side effects are rare, affecting less than one in 100 people taking venlafaxine.

Serious side effects of venlafaxine and when to call 111

Guidance from the NHS highlights that you should book an appointment with your doctor if you gain or lose weight without trying or experience significant changes to your periods – this can include bleeding between periods, heavy bleeding, or spotting. Otherwise, patients are urged to call their doctor or 111 if they experience the following side effects:

• The whites of your eyes or skin turn yellow
• Bleeding from the gums
• Bruises that appear without a reason or that get bigger
• You have thoughts about harming yourself or ending your life
• Unexplained muscle pain or weakness
• Shortness of breath, or a fast or irregular heartbeat
• You experience feelings of overwhelming happiness (euphoria), excessive enthusiasm or excitement, or a feeling of restlessness that means you cannot sit or stand still
• Any changes in eyesight, such as blurred vision or dilated pupils
• You cough up blood
• Have blood in your pee
• You get constant headaches, long-lasting confusion, weakness, or frequent muscle cramps
• You have black or red poo, or blood in your vomit – these can be signs of bleeding in the stomach

It’s important to remember that the NHS states long-term use of venlafaxine is generally safe with no lasting effects. Nonetheless, if you have concerns about any side effects related to your medication, you should consult a qualified pharmacist, doctor, or appropriate health professional.

Further guidance on venlafaxine can be found on the NHS website here.