Ethinylestradiol + Desogestrel

Indications
Desogestrel & Ethinylestradiol is indicated in prevention of pregnancy or oral contraception.

Therapeutic Class
Oral Contraceptive preparations

Pharmacology
Desogestrel is a progestogen that is structurally related to levonorgestrel while ethinylestradiol is a synthetic oestrogen. Used together, they inhibit ovulation by a negative feedback mechanism on the hypothalamus, which alters the normal FSH and LH secretion pattern by the anterior pituitary. It inhibits the follicular phase FSH and midcycle surge of gonadotropins. It also causes changes in the cervical mucus, making it unsuitable for sperm penetration. It may also alter tubal transport of the ova through the fallopian tubes. Progestational agents may also alter sperm fertility.

Dosage & Administration
Dosing instruction may vary according to the brand.
For 21-day pack: Start dose on 1st day of menstrual cycle. 1 tablet daily for 21 days followed by 7 pill-free days. Start a new pack on the 8th day after the last tablet is taken.
For 28-day pack: Start dose on 1st day of menstrual cycle. 1 tablet daily without interruption.
Dose should be taken at the same time everyday.

Interaction
Serum levels may be increased when used with paracetamol, ascorbic acid, atorvastatin. Serum levels may be reduced by aprepitant, griseofulvin, modafinil, troglitazone, rifampicin, topiramate, nevirapine, amprenavir, lopinavir, nelfinavir and ritonavir. May affect the efficacy of coumarin derivatives. Concurrent use with aminoglutethimide, carbamazepine, felbamate, phenobarbital, phenytoin or topiramate may lead to decrease in contraceptive effectiveness. May reduce the clearance of alprazolam, chlordiazepoxide and diazepam. May increase the clearance of lorazepam, oxazepam, temazepam, clofibric acid, morphine, salicylic acid. May inhibit the metabolism of theophylline, ciclosporin and prednisolone. May decrease the serum levels of lamotrigine. May increase serum levels of selegiline and TCAs e.g. amitriptyline, imipramine.

Contraindications
History of or current thrombophlebitis or venous thromboembolic disorders; active or recent (within 1 yr) arterial thromboembolic disease e.g. stroke, MI; cerebral vascular disease, coronary artery disease, valvular heart disease with complications. Severe hypertension; DM with vascular involvement; severe headache with focal neurological symptoms. Known or suspected breast carcinoma, endometrial cancer, oestrogen-dependent neoplasms. Undiagnosed abnormal genital bleeding; hepatic dysfunction or tumor. Cholestatic jaundice of pregnancy, jaundice with prior combined hormonal contraceptive use. Major surgery with prolonged immobilisation. Pregnancy.

Side Effects
Intermenstrual bleeding, post-medication amenorrhoea, changes in cervical secretion, increase in size of uterine fibromyomata, aggravation of endometriosis and certain vaginal infections. Breast tenderness, pain, enlargement or secretion. Nausea, vomiting, cholelithiasis, cholestatic jaundice. Headache, migraine, mood changes, depression. Fluid retention, change in body wt, reduced glucose tolerance.

Pregnancy & Lactation
Category X: Studies in animals or human beings have demonstrated fetal abnormalities or there is evidence of fetal risk based on human experience or both, and the risk of the use of the drug in pregnant women clearly outweighs any possible benefit. The drug is contraindicated in women who are or may become pregnant.

Precautions & Warnings
May increase risk of breast cancer, glucose intolerance and thromboembolism. May affect serum levels of triglyceride and lipoprotein. Caution when used in patients with familial defects of lipoprotein metabolism. Discontinue treatment if papilledema or retinal vascular lesions are observed on eye examination. Patients with risk factors for coronary artery disease. Patients with depression or history of migraine. Renal impairment. Increased cardiovascular risk in smoking women especially those >35 yr. Treatment should be stopped for 4 wk prior to and for 2 wk after surgery associated with increased risk of thromboembolism or during periods of prolonged immbolisation.

Overdose Effects
Treatment is symptomatic.

Storage Conditions
Store at 25°C.