🔴 Mechanism of Action 🔴

🔺 Hormonal contraceptives

🔸A. Female contraceptives :-

1. Inhibition of Gn release from pituitary by reinforcement of normal feedback inhibition.

Suppression of Ovulation is the primary mode of action of combined oral pill.

2. Thick cervical mucus secretion hostile to sperm penetration is evoked by progestin action.

3. Even if ovulation and fertilization occur, the blastocyst may fail to implant because endometrium is either hyperproliferative or hypersecretory or atrophic and in case out of phase with fertilization..... Not suitable for nidation .

4. Uterine and tubular contraction.

5. The postcoital pill may dislodge a just implanted blastocyst or may interfere with fertilization/implantation.

🔸B. Male contraceptives :-

1. Antiandrogens Depress spermatogenesis, but raise Gns; cause unacceptable loss of libido.

2. Estrogens and progestins Act by suppressing Gns-cause
unacceptable feminization.

3. Androgens:- They inhibit Gns but have poor efficacy.
Even combination with progestin ts not reliable.

4. Superactive Gn RH analogues They inhibit Gn release
by continuous action: inhibit testosterone secretion as well;
produce impotence. loss of libido.

5. Cytotoxic drugs Cadmium, nitrofurans and indoles
suppress spermatogenesis, but are toxic.

6. Gossypol It is a nonstcroidal compound, obtained
from con on seed which has been studied in China. It
is effective orally--causes suppression of spermatogenesis
and reduces sperm motility- infertility develops after a
couple of months. Fertility is restored several months
after discontinuation. However, about 10% men remain
oligozoospermic. During treatment serum LH and testosterone levels do not change: libido and potency arc not affected. The mechanism of action though not clearly
known, appears to involve direct toxicity on seminiferous epithelium.
Most important adverse effect of gossypol is hypokalaemia (due to renal loss of POTASSIUM with its attendant muscular
weakness (even paralysis). Other side effects are.....edema,
diarrhoea. breathlessness and neuritis. Its use has now
been dropped.

🔴ADRS OF HARMONAL CONTRACEPTIVE 🔴
🅰️ Nonserious
✅Nausea
✅Vomiting
✅Morning sickness of pregnancy
✅Headache
✅Breast discomfort
✅Weigjt gain
✅Cholasma
✅Pruritus vulvae
✅Mood swings
🅱️Serious
✅Leg vein thrombosis
✅Coronary and cerebral
✅thrombosis results in stroke
✅Rise in BP
✅genital carcinoma
Gallstones

🔴 Mechanism of Action 🔴

🔺 Oxytocin :- It is a nonpeptide secreted from posterior pituitary along with Argenine Vasopressin (AVP or ADH) .

🔺Actions :-

1. Uterus :- Oxytocin increase the force and frequency if uterine contractions and basal tone increases only with high doses.

🔸Mechanism :- Oxytocin bind with G-protein coupled receptors located on myometrium which mediate response mainly depolarization of muscle fibres and influx of CALCIUM ions as well as through phosphoinositide hydrolysis and IP3 ( ionositol triphosphate) mediated intracellular release of CALCIUM ions.

Oxytocin also increase the PG (prostaglandin) synthesis and release by endometrium which may contribute to the contractile response.

2. Breast :- Facilitate milking.

3.CVS :- Umbilical vessels closure at birth.

4.Kidney :- Exerts ADH (Antidiuretic hormone )like effect at high doses.

🔺Physiological Role:-

1. Induce Labour

2. Milk ejection reflex

3. Neurotransmission