Table 1.

Examples of complex drug interactions and suggested management ¹¹

Interacting drug	Indications for use	Effect of ritonavir	Comments
Clopidogrel	Antiplatelet agent	↓ production of clopidogrel active metabolite	Contraindicated if very high risk of thrombosis (e.g. stents placed in last 6 weeks). Could consider use in other situations
HMG Co‐A reductase inhibitors	Hyperlipidaemia	↑ Simvastatin and atorvastatin levels	Simvastatin contraindicated: withhold and recommence 3 days after Paxlovid® ceased. Could use lower dose atorvastatin, or withhold during and 3 days after Paxlovid
Quetiapine	Psychotropic	↑ quetiapine area under the curve by five‐ to eightfold	Contraindicated. Could consider significant dose reduction during and 3 days after Paxlovid course with careful monitoring