The responsibility to dispense the right medication for each patient lies with both pharmacists and physicians, who must carefully consider all factors that may affect its efficacy or safety, including potential drug interactions.
What are Drug Interactions?
Drug interactions happen when a drug interacts with another drug, or with a specific food, beverage, or supplement, which ultimately alters its effectiveness or causes unexpected side effects. Such interactions may make medications less effective, dangerously more potent, or result in new or bothersome side effects.
Some drug interactions can even be fatal. Therefore, knowledge of potential drug interaction prior to prescribing or dispensing any medication is a must.
There are 3 ways in which drug interactions can happen:
- Drug-Drug interaction: Two or more drugs interact with each other, causing undesirable effects. For example, combining a sedative with an antihistamine results in increased drowsiness, making it dangerous to drive or operate heavy machinery and increasing the risk of falls.
- Drug-Disease interactions: This is when a drug affects a specific health condition, or conversely, when a health condition affects the effectiveness or the side effects of certain medications. Common examples include asthma and propranolol, hypertension and decongestants containing “pseudoephedrine”, or liver disease and paracetamol.
- Drug-Food/Drink interactions: A drug interacting with certain foods or beverages. For example, drinking grapefruit juice with certain drugs may intensify their associated side effects or lower their effectiveness, depending on the type of drug.
Examples of Common and Significant Drug Interactions
Below are a few notable examples of drug-condition interactions:
- Sildenafil (Viagra) and Nitrates: Viagra (Sildenafil) should not be combined with nitrates (such as Isosorbide dinitrate), which are used to treat heart disease. This combination can cause a dangerously low or even fatal blood pressure.
- Doxycycline and Multivitamins: When doxycycline is co-administered with multivitamins, it can reduce its absorption and effectiveness. Patients should be advised to separate them at least 2-4 hours.
- Digoxin and Amiodarone: Amiodarone and digoxin can be taken together, but with caution. Amiodarone can increase digoxin levels, leading to toxicity risk. To prevent this, when prescribed together healthcare providers often lower digoxin dose and monitor its blood levels closely. They also make sure to educate patients about toxicity symptoms.
- Warfarin and NSAIDs: Nonsteroidal anti-inflammatory drugs, particularly aspirin, may increase the risk of bleeding. When taken together with a blood thinner such as warfarin the risk of bleeding becomes significantly higher.
- Levothyroxine and Omeprazole: Omeprazole, a PPI, can reduce the absorption of levothyroxine (a thyroid medication), which may consequently lower its efficacy.
- Ondansetron and Dofetilide: Ondansetron, used for nausea and vomiting, may interact with dofetilide, a drug that regulates heart rhythm. This interaction can prolong the interval between heartbeats, leading to dizziness, fainting, and in severe cases, death.
- Potassium supplements and Spironolactone (diuretic): When taken together, these two medications can cause potassium levels to become too high, causing severe heart issues that could be life-threatening.
- Theophylline and Ciprofloxacin: Theophylline (used for certain respiratory diseases) can interact with the antibiotic ciprofloxacin, leading to toxic blood levels of theophylline and serious life-threatening side effects.
- Selegiline with Pseudoephedrine: Taking selegiline (a type of MAOI), with pseudoephedrine (commonly found in decongestants and cold medications) may cause dangerously high blood pressure, and in some cases may even be fatal. Drugs containing pseudoephedrine should be avoided until at least 14 days after discontinuing selegiline.
- Carbamazepine and Clarithromycin: Carbamazepine (an anticonvulsant) and Clarithromycin (an antibiotic) should not be used simultaneously because Clarithromycin can increase the levels of Carbamazepine in the blood, raising the risk of toxic side effects. A safer alternative or dosage adjustment should be considered.
Note: These are only a few examples and do not cover all possible drug interactions.
How to Avoid Drug Interactions?
Here are the key tips to reduce the risk of drug interaction:
1- Effective Communication
- Listen Carefully: Ask about all medications that the patient is currently taking, including any prescribed, over-the-counter medicines, dietary supplements, and herbs.
- History Taking: Ensure you are aware of all the patient’s medical conditions.
- Discuss Treatment Plan: Explain how and when to take the drug and any special precautions that the patient should be aware of.
- Encourage Communication: Encourage the patient to inform you of any changes in their health conditions or medication regimen.
2- Using “Wasfaty”
“Wasfaty” is one of nupco’s services. It is an electronic system that links hospitals and primary health care centers with community pharmacies. Helping improve quality of healthcare and pharmaceutical services provided to patients by:
- Easier Access to Medications: Patients can receive their medications for free at the nearest community pharmacy.
- Better Patient Safety: Wasfaty system automatically checks for allergies, potential drug interactions, and drug-disease interactions.
- Minimization of Medical Errors: Wasfaty system rejects any prescription containing a warning about drug incompatibility with the patient’s health condition or with other prescribed medications.
For more information on “Wasfaty” services, please visit the “Frequently Asked Questions” page on our website.
3- Staying Updated on Drug Interactions
- Stay updated, especially with most commonly prescribed and narrow therapeutic index medications.
- Follow the latest updates from reliable sources.
- Regularly read medical and pharmaceutical journals.
- Attend conferences and seminars on drug interactions.
- Go through the drug leaflet in case of doubt, or discuss it with your colleagues if you have any queries or concerns.
Conclusion
Proper understanding and avoidance of drug interactions is important for patient safety. With effective communication, utilizing smart programs, and staying updated, healthcare professionals can minimize the risks associated with drug interactions and ensure optimal patient care.