Lopinavir with ritonavir

How it works

Lopinavir inhibits HIV protease, preventing cleavage of viral polyproteins into mature functional proteins, while ritonavir inhibits CYP3A4 to raise and sustain lopinavir plasma concentrations.

Prescribing in practice

• Through potent CYP3A4 inhibition by ritonavir, the combination has extensive and potentially serious drug interactions, so all co-medication must be checked against the SPC before use.
• It can prolong the PR and QT intervals and cause dyslipidaemia, pancreatitis and gastrointestinal upset, warranting caution in those with conduction or metabolic risk.
• The oral solution contains alcohol and propylene glycol and is unsuitable for neonates, particularly preterm infants, because of toxicity risk.

Monitoring

Monitor HIV viral load and CD4 count together with lipids, glucose, liver function and, where indicated, ECG.

Counselling the patient

• Take doses as prescribed and do not stop without advice to avoid loss of viral control.
• Always check before starting new medicines, including those bought over the counter.
• Report severe abdominal pain, persistent diarrhoea or palpitations.

Evidence & guidelines

Use is informed by the SPC and its established place in UK HIV treatment guidance, including roles in second-line and certain specific settings.