Interactions Of OTC medicines

Question 1

What does Aspirin interact with & what is the nature of the interaction ?

Answer 1

Anticoagulants, antiplatelets and thrombolytics Increased risk of bleeding due to antiplatelet effect

Carbonic anhydrase inhibitors (acetazolamide) Increased plasma levels of acetazolamide

Cytotoxics (methotrexate)
Reduced excretion of methotrexate

NSAIDs, corticosteroids
Increased likelihood of stomach irritation and gastro-intestinal bleeding

Uricosurics (sulfinpyrazone) Reduced uricosuric effects

Vitamin C - Aspirin - Reduced vitamin C absorption

Vitamin E - Aspirin - May increase the risk of bleeding

Question 2

What do NSAIDs (ibuprofen, naproxen) interact with & what is the nature of the interaction ?

Answer 2

ACE inhibitors, angiotensin II inhibitors, potassium salts, potassium-sparing diuretics, trimethoprim Increased risk of hyperkalaemia and renal impairment; increased blood pressure

Antibacterials (quinolones)- Increased risk of convulsions

Antihypertensives, diuretics Reduced diuretic and antihypertensive effect

Other NSAIDs (including aspirin), corticosteroids, anticoagulants	
Increased likelihood of stomach irritation or bleeding (NSAIDs, anticoagulants), reduced antiplatelet effects (aspirin)

Methotrexate- Increased toxicity

Lithium- Reduced excretion

Tacrolimus - Increased risk of nephrotoxicity

Question 2

What does Hyoscine butylbromide interact with & what is the nature of the interaction ?

Answer 2

Tricylic antidepressants, antipsychotics, antihistamines, quinidine, anticholinergics (eg ipratropium, tiotropium) Intensifies antimuscarinic effect

Question 3

What does Paracetamol interact with & what is the nature of the interaction ?

Answer 3

Alcohol Increased susceptibility to liver damage in heavy drinkers

Colestyramine Reduced absorption of paracetamol

Antiemetics (metoclopramide, domperidone) Increased rate of absorption of paracetamol

Question 4

What does Codeine interact with & what is the nature of the interaction ?

Answer 4

Antidepressants, antihistamines, alcohol, antipsychotics, anxiolytics, hypnotics, concurrent opioid analgesics - Increased sedation

Question 5

What does Mebendazole(ovex) interact with & what is the nature of the interaction ?

CHANGE FLASH CARD SAM

Answer 5

Mebendazole Carbamazepine, phenytoin Lowers plasma mebendazole
Metronidazole - Increased risk of Stevens-Johnson syndrome

Question 6

What does Omeprazole, Esomeprazole interact with & what is the nature of the interaction?

Answer 6

Antifungals (itraconazole, ketoconazole) - Reduced absorption of these drugs
Anxiolytic (diazepam) - Enhanced effect of diazepam
Cilostazol - Increased plasma levels of cilostazol
Clopidogrel - Reduced efficacy of clopidogrel
Voriconazole - Increased plasma levels of omeprazole/esomeprazole

Question 7

What does Loratadine interact with & what is the nature of the interaction?

Answer 7

MAOIs (phenelzine, tranylcypromine) Increased risk of antimuscarinic adverse effects

Question 8

What does Omega 3 interact with & what is the nature of the interaction?

Answer 8

Fish oil/cod liver oil (EPA & DHA) Antihypertensives May reduce blood pressure
Anticoagulants, antiplatelets - May increase anti-clotting effects, leading to bleeding

Question 9

What Vitamins/supplements does Warfarin interact with ?

Answer 9

Vitamin K Anticoagulants (eg warfarin)

Cranberry- Warfarin - May inhibit breakdown of warfarin in the body, leading to increased warfarin activity. “in otherwise healthy individuals, moderate doses of cranberry juice are unlikely to have an important impact on anticoagulation control.”

Fish oil/cod liver oil (EPA & DHA) - May increase anti-clotting effects, leading to bleeding

Garlic Anticoagulants, antiplatelets May increase anti-clotting effects, leading to bleeding
Ginger