Various adverse reactions have been associated with oral contraceptive use. The serious reactions are dealt with in more detail. The first appearance of symptoms indicative of any one of these reactions necessitates immediate cessation of oral contraceptive use while appropriate diagnostic and therapeutic measures are undertaken.
Serious adverse reactions: Some epidemiological studies have suggested an association between the use of COCs and an increased risk of arterial and venous thrombotic and thromboembolic diseases such as myocardial infarction, stroke, deep venous thrombosis, and pulmonary embolism. These events occur rarely.
Thrombosis has very rarely been reported to occur in other veins or arteries, e.g. hepatic, mesentric, renal or retinal, in COC users. There is no consensus as to whether the occurrence of these events is associated with the use of COCs.
The use of estrogen-containing oral contraceptives may promote growth of existing sex steroid dependent tumours. For this reason, the use of these oral contraceptives in patients with such tumours is contraindicated.
The possible increase in risk of breast cancer should be discussed with the user and weighed against the benefits of COCs taking into account the evidence that they offer substantial protection against the risk of developing certain other cancers (e.g. ovarian and endometrial cancer).
The use of oral contraceptives may sometimes lead to the development of cholestatic jaundice or cholelithiasis.
On rare occasions the use of oral contraceptives may trigger or reactivate systemic lupus erythematosus.
A further rare complication of oral contraceptive use is the occurrence of Sydenhams' chorea which can be reversed by discontinuing the pill. The majority of cases of oral contraceptive-induced chorea show a pre-existing predisposition which often relates to acute rheumatism.
Other Adverse Reactions: Cardiovascular system: rise of blood pressure. If hypertension develops, treatment should be discontinued.
Genital tract: intermenstrual bleeding, post-medication amenorrhoea, changes in cervical secretion, increase in size of uterine fibromyomata, aggravation of endometriosis and certain vaginal infections, e.g. candidiasis.
Breast: tenderness, pain, enlargement, secretion.
Gastro-intestinal tract: nausea, vomiting, cholelithiasis, cholestatic jaundice.
Skin: erythema nodosum, rash, chloasma.
Eyes: discomfort of the cornea if contact lenses are used.
CNS: headache, migraine, mood changes. depression.
Metabolic: fluid retention, change in body weight, reduced glucose tolerance.