Prostaglandins: What They Do and Why They Matter

Prostaglandins are small signaling chemicals your body makes on demand. They act locally near the cells that make them and change how tissues behave within minutes to hours.

How prostaglandins work

Your body makes prostaglandins from fatty acids called arachidonic acid using COX enzymes. Different COX enzymes produce different prostaglandin families. PGE2 often drives pain, fever, and inflammation. PGF2α causes strong muscle contractions in the uterus. PGI2, or prostacyclin, relaxes blood vessels and slows clotting, while TXA2, thromboxane, tightens vessels and promotes clotting.

This balance explains why drugs that change prostaglandin production have big effects. NSAIDs like ibuprofen and naproxen block COX enzymes, lowering many prostaglandins to reduce pain and fever. That helps symptoms but can weaken the stomach’s protective prostaglandins, raising the risk of ulcers. In pregnancy, NSAIDs late in gestation can cause the fetal ductus arteriosus to close too early, so doctors avoid them in the third trimester.

What this means for you

Doctors use prostaglandin-based drugs for several clear reasons. Misoprostol protects the stomach from ulcer damage caused by NSAIDs and also causes uterine contractions; it’s used for medical abortion and for inducing labor in controlled settings. Dinoprostone and other prostaglandin analogs help ripen the cervix before induction. Latanoprost eye drops lower eye pressure by improving fluid outflow and are a mainstay of glaucoma treatment.

Side effects depend on the drug and dose. Common effects include cramping, diarrhea, flushing, and increased bleeding risk. With eye drops you might notice longer eyelashes and darker iris color over time. Always tell your clinician about pregnancy or plans to become pregnant before starting medications that affect prostaglandins.

You won’t see routine lab tests for prostaglandins in everyday care; measurements are mainly for research or specific medical situations. Instead, clinicians judge prostaglandin action by symptoms and by using drugs that change their levels.

Quick practical tips: avoid NSAIDs in late pregnancy unless a doctor says otherwise; if you use prostaglandin eye drops follow instructions and report eye changes; ask your provider about alternatives if a prostaglandin drug causes strong cramps or heavy bleeding. If you’re ever unsure, a short call to your pharmacist or clinician can clear up risks and safer options.

Researchers are studying selective COX-2 inhibitors and drugs that change specific prostaglandin receptors to get benefits without common side effects. Some newer heart and pain medicines aim to preserve protective prostaglandins in the stomach while cutting the ones that cause pain and clotting. That work may mean safer pain relief and lower ulcer rates in people who need long-term therapy. If you have heart disease, asthma, or a history of ulcers, mention those conditions when a clinician talks about NSAIDs or prostaglandin analogs. Also discuss timing around pregnancy and breastfeeding. Small changes—like trying acetaminophen first for mild pain or using the lowest effective NSAID dose for the shortest time—can reduce risk. Keep a list of your meds and share it at every visit.

Small questions can prevent serious side effects.