Sunday, October 19, 2014

Drug drug interaction

My friend, XY is a counsellor. She has a client who was taking Valdoxan (agomelatine) and Seroquel (Quetiapine) for depression. Recently her client was stress and smoke marijuana / cannabis at the same time. XY asked whether there are any drug-drug interaction among these 3 drugs and can that cause panic attack in her client? 

Identify drug-drug interaction on a prescription is also one of the job of pharmacist. 90% of the time, drug-drug interaction was not significant and thus do not require any adjustment but just closer monitoring. However, sometime, drug-drug interaction require some of the drugs on the prescription to be changed to a safer alternative.

A check on agomelatine showed that this drug is available in Malaysia. It is a melatonin type of antidepressant from Servier company. It is often used as 25mg once daily at bedtime. As it is a CYP1A2 substrate, the drug is not suitable to be co-administered with flucoxamine and ciprofloxacin, which are potent CYP1A2 inhibitor. 

There are few drug interaction checker available online and on mobile apps. The reliable one include www.drugs.com, MIMS gateway and Micromedex drug interaction checker. Upon entering the 3 drugs in the checker found that interaction exist between quetiapine and cannabis. Using both agents together increase sedation, drowsiness and dizziness. The patient will also not able to concentrate and has trouble making judgment. Panic attack is not listed in it and may require further search on certain case reports or other literature. 

Pharmacists often overlook drug-drug interaction due to lack of knowledge and not familiar with the prescribed medications. Regular updates on drugs, using interaction checker and create pop-up messages in the computer system will help us in identifying these interaction.