Published: 3 March 2022

Publications

Reminder: Counsel patients about symptoms and signs of venous thromboembolism when prescribing combined oral contraceptives

Published 3 March 2022
Prescriber Update 43(1): 2–3
March 2022

Following the report of a fatal pulmonary embolism (PE) in a young woman on a combined oral contraceptive (COC) in 2021, the Medicines Adverse Reactions Committee (MARC) asked Medsafe to remind prescribers to ensure patients taking COCs are aware of the symptoms and signs of venous thromboembolism (VTE).

Raise awareness of VTE when prescribing COCs

VTE may occur at any time during use of a COC. However, the risk of VTE is highest during the first year after starting a COC and when restarting after a break of four weeks or more.^1,2

Prescribers are reminded to counsel patients about the symptoms and signs of VTE when starting a COC and to repeat this information from time-to-time during ongoing COC use, as patients may not recall all the information they received initially.

Ensure that patients know to seek medical attention if they have a hot, swollen or painful leg, and/or if they experience chest pain, cough or shortness of breath.

Review the benefit-risk balance for COC use periodically

The risk of VTE associated with COC use is discussed in a previous issue of Prescriber Update.² Briefly, evidence from observational studies suggests that current COC use is associated with a 3- to 3.5-fold increase in the risk of VTE compared with non-use.¹

Despite this increase in the relative risk of VTE compared to non-use, the absolute risk of VTE in current COC users remains low.^1,3 The absolute risk of VTE associated with COC use varies depending on the type of progestogen (Table 1).³

Factors that increase the risk of VTE associated with COC use include (but are not limited to) current or previous VTE, inherited or acquired thrombophilia (eg, antiphospholipid syndrome), major surgery, trauma, prolonged immobility, post-partum, smoking, obesity, and older age.^4–6 Prescribers are reminded to periodically reassess the risk of VTE in patients using a COC to ensure the benefits of use continue to outweigh the risks of harm. Consult the New Zealand data sheet for Contraindications (section 4.3) and Special warnings and precautions (section 4.4) relating to specific COCs.

Table 1. Estimated risk of venous thromboembolism (VTE) associated with different types of progestogens contained in combined oral contraceptives (COCs)^a

Progestogen type	Estimated risk of developing VTE in a year (incidence per 10,000 women)
Levonorgestrel Norethisterone	5–7
Desogestrel Drospirenone Cyproteroneb	9–12

Notes:

1. Includes progestogens used in COCs containing <50 mcg ethinylestradiol that are currently available in New Zealand.
2. Cyproterone-containing COCs are indicated only for use in women requiring treatment for androgen dependent conditions such as acne (where local treatment or oral antibiotics have not been successful, hirsuitism or androgenic alopecia). See the Ginet and Diane 35 ED data sheets for more information (available at: medsafe.govt.nz/Medicines/infoSearch.asp).

Source:

European Medicines Agency. 2014. Benefits of combined hormonal contraceptives (CHCs) continue to outweigh risks 16 January 2014. URL: ema.europa.eu/en/documents/referral/benefits-combined-hormonal-contraceptives-chcs-continue-outweigh-risks_en.pdf (accessed 18 January 2022).

Maintain a high index of suspicion of VTE in COC users

Patients with VTE may be asymptomatic or present with non-specific symptoms such as calf tightness, chest pain or cough. Always be mindful of the possibility of VTE in COC users and follow local guidelines for the investigation and management of suspected VTE as necessary.

More information

The Health Navigator website has information for patients and clinicians.

• Deep vein thrombosis
• Pulmonary embolism
• Combined oral contraceptive pill

References

1. Faculty of Sexual & Reproductive Healthcare (FSRH). 2019. FSRH Guideline: Combined Hormonal Contraception January 2019 (amended November 2020) 1 November 2020. URL: fsrh.org/standards-and-guidance/fsrh-guidelines-and-statements/method-specific/ (accessed 18 January 2022).
2. Medsafe. 2018. Using New Zealand data to review the risk of venous thromboembolism with combined oral contraceptives. Prescriber Update 39(2): 23–4. URL: medsafe.govt.nz/profs/PUArticles/June2018/NZDataVenousThromboembolismOralContraceptives.htm (accessed 18 January 2022).
3. European Medicines Agency. 2014. Benefits of combined hormonal contraceptives (CHCs) continue to outweigh risks 16 January 2014. URL: ema.europa.eu/en/documents/referral/benefits-combined-hormonal-contraceptives-chcs-continue-outweigh-risks_en.pdf (accessed 18 January 2022).
4. New Zealand Formulary (NZF). 2022. NZF v115: Combined oral contraceptives 1 January 2022. URL: nzf.org.nz/nzf_70965 (accessed 18 January 2022).
5. Faculty of Sexual & Reproductive Healthcare (FSRH). 2016. UKMEC April 2016 Summary Sheet (Amended September 2019) 1 April 2016. URL: fsrh.org/standards-and-guidance/documents/ukmec-2016-summary-sheets/ (accessed 19 January 2022).
6. Ministry of Health. 2020. New Zealand Aotearoa’s guidance on contraception 7 December 2020. URL: health.govt.nz/publication/new-zealand-aotearoas-guidance-contraception (accessed 19 January 2022).