Key Learnings:
This session highlighted that both oestrogen and progestogens are metabolised by Cytochrome P450, and hence DDIs (drug-drug interactions) might lead to a reduced effect of the contraception. However, it was noted that INSTIs (Integrase inhibitors) as well as NRTIs (Nucleoside Reverse Transcriptase Inhibitors including PEP and PrEP) have not been shown to cause any DDIs.
The presentation also outlined that Boosted PIs (Protease Inhibitors) lower oestrogen levels which can lead to more irregular bleeding, so we must use a minimum dose of 30mcg oestrogen/day with the COC (combined oral contraceptive pill). Progestogen levels tend to increase (so is still efficacious) leading to greater hormonal side effects such as acne and nausea. Conversely, EFV (Efavirenz) lowers progestogen levels, and therefore will affect contraception efficacy. Only Levonogestrel-IUD (and Cu-IUD) and depot medroxyprogesterone acetate (DMPA) are safe to use.
Following this presentation, I feel more confident in prescribing contraception for women on ARVs, can guide colleagues more effectively, and promote the Liverpool Drug Interactions website. Ultimately, IUDs are usually a good, safe, and effective first line choice for women with or without HIV, particularly if other chronic diseases such as Epilepsy and Tuberculosis are concurrent.
Author bio:
Charlie is an East London trained GP with a special interest in Sexual and Reproductive Health. She currently works at Cairns North Sexual Health Clinic and as a GP as an HIV s100 prescriber.
