Boils and STIs Are Not the Same Problem

Walk into any drugstore in Metro Manila with a lump on your arm and you will likely be handed an antibiotic—most often amoxicillin—before anyone has looked at it properly. Boils (pigsá in Tagalog) are usually caused by Staphylococcus aureus entering a hair follicle, often after friction from a collar, a sweaty tricycle ride, or a nick from shaving. Sexually transmitted infections are a different story entirely: gonorrhea and chlamydia come from specific bacteria that live on mucous membranes, and the antibiotics that cure one rarely cure the other.

The confusion is understandable. Both involve bacteria, both get treated with capsules, and both attract a lot of guesswork in pharmacies where a pharmacist may or may not be on duty. But the stakes are different. A boil that is lanced and drained badly can spread; an untreated chlamydia infection can cause pelvic inflammatory disease and infertility in women before a single symptom shows up.

This page covers what the drugs actually do, what they cost here, and where the common self-medication habits go wrong.

Amoxicillin for Boils: How Many Days and What It Costs

Amoxicillin is the antibiotic most Filipino households reach for, and it is one of the cheapest. A 500 mg capsule of a branded product like Britamox runs roughly 8 to 15 pesos at a community pharmacy, while generic amoxicillin can be had for under 5 pesos per capsule in some outlets. A standard seven-day course at three capsules a day therefore costs somewhere between 100 and 300 pesos—enough that people often stop at day three when the swelling goes down.

That is the first mistake. A boil that improves by day three can flare again if the course is cut short, and repeated half-courses are exactly how resistant S. aureus gets selected. Most clinicians will prescribe five to seven days of amoxicillin for a mild boil, but the drug has limits: many S. aureus strains now produce beta-lactamase, an enzyme that breaks amoxicillin down, and a penicillinase-resistant option such as cloxacillin or cephalexin is often the better choice for a stubborn or recurrent boil.

When a boil needs more than a capsule

If the boil is larger than a five-peso coin, hot, and clearly filled with pus, antibiotics alone will not drain it. Warm compresses help, but a doctor may need to incise and drain it. Do not squeeze a boil on the face—the drainage can track toward the eye and cause a serious infection. For anyone with diabetes, a boil that keeps coming back deserves a blood sugar check before another prescription.

STI Treatment: What Amoxicillin Cannot Do

Amoxicillin and mefenamic acid are frequently taken together—mefenamic for the pain, amoxicillin for whatever the patient assumes is the infection. This combination is fine for a feverish sore throat or a painful boil, but it does nothing for gonorrhea or chlamydia. Gonorrhea is treated with a single injection of ceftriaxone plus oral azithromycin or doxycycline; chlamydia needs doxycycline for a week. Neither responds to amoxicillin at any sensible dose.

The list of antibiotics used for STIs is short and specific: ceftriaxone, azithromycin, doxycycline, and in some cases benzathine penicillin for syphilis. Antibiotics sold for female STI symptoms over the counter—often a fluoroquinolone handed out without a prescription—have driven resistance up sharply, and ciprofloxacin is no longer recommended as first-line gonorrhea treatment in the Philippines for that reason.

If you have discharge, burning on urination, or a partner with symptoms, a free or low-cost test at a social hygiene clinic in your city hall is the right first step, not a pharmacy counter. These clinics operate in most cities and municipalities, and many offer confidential testing and treatment at minimal cost.

Pharmacy Habits That Cost More Than They Save

Self-medicating with leftover amoxicillin is common because a full course often leaves extra capsules, and people keep them in a drawer for the next fever. The habit is worth breaking. Dosing depends on weight, the site of infection, and kidney function, and a capsule chosen for a sore throat is not the right one for a boil or a pelvic infection.

Check the pharmacy before you buy. Large chains and hospital pharmacies tend to have a licensed pharmacist on site who can tell you whether a prescription is needed; smaller outlets may not. Ask for the generic name and compare the price—amoxicillin from a Philippine generics manufacturer is the same molecule as a branded version at a fraction of the cost. Read the label for the expiry date, and never buy loose capsules from an open bottle.

The plainest advice: for a boil, see a doctor if it is large, painful, or recurrent; for any suspected STI, get tested before you swallow anything. Both are treatable, cheaply and quickly, once the right diagnosis is made.