Drug interaction: Pharmacist issues warning about 8 over-the-counter drug interactions that can make you ill

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Leading pharmacist warns these combinations could be dangerous 💊
  • Many people are unaware of the risks of mixing over-the-counter (OTC) drugs with prescription medications.
  • A leading pharmacist from Well Pharmacy has warned of the very real dangers of mixing prescribed and OTC medications without first seeking expert medical advice.
  • Some of the dangerous drug combinations could leave you seriously ill, including causing severe problems such as cardiovascular issues.
  • George Sandhu, deputy superintendent pharmacist for Well Pharmacy has outlined 8 dangerous drug combinations that could cause serious harm.

At some point in our life we will rely on over-the-counter (OTC) medication to help alleviate symptoms we may experience, but many people are unaware of the risks of mixing certain OTC drugs with prescribed medicines.

George Sandhu, deputy superintendent pharmacist for Well Pharmacy, has shared his concerns about using OTC medications whilst on prescription drugs and has urged patients to always check the warnings on the medicine they take as well as discussing their medication with a local pharmacist. 

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Sandhu said: “All patients should use their pharmacist as a first point for consultation over the prescription drugs, they take. The pharmacist will be able to discuss in detail exactly what side effects might occur due to the medications being taken.”

These 8 over-the-counter drug interactions that can make you ill (Photo: Pexel, Etatics Inc)These 8 over-the-counter drug interactions that can make you ill (Photo: Pexel, Etatics Inc)
These 8 over-the-counter drug interactions that can make you ill (Photo: Pexel, Etatics Inc) | Pexel, Etatics Inc

He continued: “It is also important that service users remember to read the packaging on over-the-counter medications to avoid any accidents. If in doubt, the NHS offers a variety of helpful information online which can aid anyone who might be unaware of the dangers of mixing drugs.”

Here are 8 dangerous drug combinations that could cause serious harm. 

Antacids and antibiotics

Antacids help with acid reflux but can cause an issue if a patient combines them with certain prescribed antibiotics. The major problem is that antacids can prevent the body from absorbing the antibiotics, which means they are not tackling the infection they are intended to fight. 

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To avoid this, it is recommended that patients take these pills at separate times in the day, and also discuss the issue with their pharmacist.

Antidepressants and migraine medication

Migraine medication will often feature drugs known as triptans, a group of medicines that act on the serotonin in the brain. While triptans cannot prevent a migraine from occurring, they act on the pain once it has developed. However, certain patients might also take antidepressants, which also increase serotonin levels in the body.

Too much of the chemical in the body can lead to serotonin syndrome, which varies from person to person. Some patients might have a mild case and experience symptoms presenting as shivering and diarrhoea. In more severe cases, patients can experience muscle rigidity, fever and potentially a seizure.

Anti-inflammatory drugs and blood thinners

Some over-the-counter drugs like ibuprofen are among the most common taken by UK patients. The painkiller, which also acts as an anti-inflammatory, aims to ease a variety of complaints from back pain and period pain to toothache and symptoms of cold and flu.

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Despite this, the drug should not be taken by anyone dealing with a blood clotting issue and using pills such as Warfarin, which is part of a group of drugs known as anticoagulants that aim to make blood flow through your veins more easily.

The drug is used to treat blood clots and help prevent future blood clots in patients who might have previously had one, such as in a case of deep vein thrombosis or a pulmonary embolism.

It is also used to prevent blood clots occurring in patients at a higher risk of having them in the future, like those with an irregular heartbeat, a replacement heart valve or blood clotting disorders.

If ibuprofen and warfarin are taken together there could be an increased risk of bleeding. The reason behind this is that both medications affect blood clotting and gastrointestinal bleeding can occur when the combination is taken together.

Antibiotics and statins

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Some antibiotics will be taken to tackle an infection in the body but if patients are not careful with checking the labels and discussing with a pharmacist, they may experience side effects.

Erythromycin is an antibiotic widely used to treat chest infections like pneumonia, as well as skin complaints like acne and rosacea, and dental abscesses and sexually transmitted infections (STIs).

The medicine can be taken in a variety of ways including tablets, capsules or as a liquid, which can be swallowed. While the medicine offers help in those situations it can be dangerous if taken alongside other prescription drugs. One such group of drugs are statins, which are used to combat cholesterol.

Statins aim to lower the level of low-density lipoproteins in the blood and the medication reduces the production in the liver. If a patient has too many statins in the blood this could lead to a major increased risk of muscle damage known as rhabdomyolysis.

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The potentially life-threatening condition happens when muscle breaks down and usually occurs after an injury or excessive exercise without rest. If these two medications are taken at the same time, the increased number of statins in the body can cause rhabdomyolysis.

Patients are usually advised to not take their statins while taking antibiotics in order for these side effects to be avoided.

Oral contraceptives and antibiotics

Many women take a daily contraceptive pill to avoid falling pregnant however the effectiveness of the medication can be affected by antibiotics.

A group of antibiotics known as antimycobacterials, including medications such as Rifampicin and Rifabutin, reduces the effects of the pill. Used to fight bacterial infections, they will not work on colds, flu or other viral infections because it targets the actual bacteria behind the infection.

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If the medications are mixed, the effectiveness of the contraceptive pill can wane and be seriously decreased. Patients may need to use additional contraceptive methods such as condoms while taking these antibiotics.

Antibiotics and alcohol

Pharmacists will always remind patients to read the labels on their medications when they pick up their prescription. While most will heed the advice, others may opt to enjoy a night on the town despite taking antibiotics.

Some antibiotics will leave patients seriously unwell if they combine them with alcohol. Metronidazole is used for dental and vaginal infections as well as treating infected leg ulcers and pressure sores. Anyone prescribed it should avoid alcohol while taking the medication and for 48 hours after stopping the medication.

If not, side effects can include being sick, stomach pains, an irregular heartbeat, severe headache and feeling dizzy and drowsy. 

Amoxicillin and Methotrexate

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Amoxicillin is an antibiotic that is used to treat bacterial infections including pneumonia and dental abscesses. It’s also often prescribed to provide relief to children with ear infections.

Patients can only get this drug on prescription from their local pharmacy, which decreases the risk of danger of mixing the pills with other drugs.

One such dangerous combination is mixing it with Methotrexate, which is used to treat rheumatoid arthritis, psoriasis, Crohn’s disease and other autoimmune conditions.

If a patient were to take both medications together there is a severe risk that the amoxicillin present in the body would increase the risk of methotrexate toxicity by reducing the amount of methotrexate your body clears. The two medications combining in the body can lead to a variety of complications including major or minor damage to organs.

Antihistamines and antidepressants

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Antihistamines are over-the-counter tablets used to help allergies like hay fever - and stop sufferers contending with a runny nose, watery and itchy eyes.

If a patient is on antidepressants however, antihistamines can cause some side effects. Some antidepressants can give patients a dry mouth or make it difficult for them to pass urine. If antihistamines are taken with these pills, the side effects could become even worse.

You learn more about prescription medications and possible drug interactions at NHS.UK.

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