T-20

Names: T‑20, enfuvirtide, Fuzeon 

Approved dosage: 90mg (given as a 1ml injection under the skin) twice a day. The drug has to be made up from powder. 

Tips on taking it: extensive support and advice is available to people prescribed T‑20. Doses can be prepared within 24 hours of use, so two doses can be prepared together. T‑20 can be injected into the thigh, arm or abdomen. A different injection site should be used each day to reduce problems with injection site reactions and massage, angle and speed or injection can all help to reduce the risk. 

Common side‑effects: injection site reaction but rarely a reason to stop treatment, possibly involving an itchy rash, swollen red or puffy skin, hardening of the skin, or cysts; also, diarrhoea, nausea, sinusitis, skin problems, influenza, ear infection, appetite decreased, anorexia, anxiety, nightmare, irritability, peripheral neuropathy, conjunctivitis, vertigo, nasal congestion, pancreatitis, gastro‑oesophageal reflux disease, muscle pain, influenza like illness, weakness. For reasons that aren’t properly understood, tummy problems that some protease inhibitors cause are less likely to occur in people taking T‑20. 

Rare side‑effects: abscesses at the injection site and rare hypersensitivity reaction involving difficulty breathing, fever, chills, skin rash and low blood‑pressure. 

Resistance to T‑20: resistance to T‑20 develops rapidly if an undetectable viral load is not achieved, however people who are resistant to T‑20 may still get some continuing benefit from it. 

Key drug interactions: no significant interactions recorded. 

maraviroc

Names: maraviroc, Celsentri 

Approved dosage: 300mg as two oval blue 150mg pills twice daily when combined with tipranavir/ritonavir or efavirenz or nevirapine. 150mg as one oval blue 150mg pill twice daily when combined with all other protease inhibitors. 600mg as four blue oval 150mg pills twice daily when combined with the experimental NNRTI etravirine (TMC125, Intelence).  

Tips on taking it: maraviroc should only be used by people with a type of HIV called CCR5 tropic HIV. Not everybody who has taken a lot of anti‑HIV drugs and who has resistant virus will have this type of HIV. Your HIV clinic should carry out a test called a tropism test to see if you have CCR5 tropic HIV before prescribing the drug. Take with or without food. 

Common side‑effects: liver toxicities, abdominal pain, cough, upper respiratory tract infections, sore muscles.  

Resistance to maraviroc: resistance to maraviroc is still under study and appears to occur in a different way to other anti‑HIV drugs. 

Key drug interactions: dose adjustment needed with some anti‑HIV drugs (see section on dose above). Limited information about interactions with other medicines.