7.4 Introduction to Sexually Transmitted Infections and Drugs to Treat Them

Overview of Sexually Transmitted Infections (STIs)

Sexually transmitted infections (STIs) are caused by bacteria, viruses, or parasites that spread through sexual contact. Left untreated, they can lead to infertility, organ damage, certain cancers, and even death. Nurses need to recognize symptoms, administer the right treatments, educate patients, and help prevent further transmission.

Mechanisms of Common STIs

STIs fall into three categories based on the type of pathogen involved:

• Bacterial STIs (Chlamydia, Gonorrhea, Syphilis): Bacteria invade and multiply within host tissues, causing inflammation and tissue damage. Transmitted through sexual contact or vertically from mother to child during childbirth.
• Viral STIs (HPV, HSV, HIV): Viruses enter host cells and hijack cellular machinery to replicate, leading to cell damage and triggering an immune response. Transmitted through sexual contact, blood exposure, or vertically during pregnancy/childbirth. Unlike bacterial STIs, viral infections cannot be cured but can be managed.
• Parasitic STIs (Trichomoniasis): Parasites attach to and feed on host cells, causing inflammation and irritation. Transmitted through sexual contact.

Key Symptoms of Prevalent STIs

Many STIs share overlapping symptoms, and some individuals remain asymptomatic carriers who can transmit the infection without showing any signs. This is why screening matters so much.

• Chlamydia: Often asymptomatic. When symptoms appear, they include abnormal vaginal or penile discharge, burning during urination, and pelvic pain in women.
• Gonorrhea: Also frequently asymptomatic. May present with thick, cloudy, or bloody discharge, painful urination, and pelvic pain in women.
• Syphilis progresses through distinct stages:
  1. Primary: Painless sore (chancre) at the site of infection
  2. Secondary: Skin rash (often on palms and soles), fever, swollen lymph nodes
  3. Latent: No symptoms, but the infection remains in the body
  4. Tertiary: Damage to internal organs (heart, brain, nerves), potentially fatal if untreated
• HPV: Causes genital warts and abnormal cervical cell changes that can become precancerous or cancerous.
• HSV: Painful, fluid-filled blisters or sores on or around the genitals, rectum, or mouth. Initial outbreaks often include flu-like symptoms (fever, body aches, swollen lymph nodes).
• HIV: Flu-like symptoms within 2-4 weeks of infection, followed by a prolonged asymptomatic period. Without treatment, the virus progressively destroys CD4+ T cells, weakening the immune system and leading to opportunistic infections and cancers (AIDS).
• Trichomoniasis: Foul-smelling vaginal discharge (often yellow-green and frothy), genital itching or irritation, and pain during urination or intercourse.

Diagnostic Approaches for STIs

Physical examination includes inspecting the genital area for sores, warts, or discharge and palpating lymph nodes for swelling. However, because many STIs are asymptomatic, lab testing is essential.

Laboratory tests include:

1. Nucleic Acid Amplification Tests (NAATs): The gold standard for detecting Chlamydia and Gonorrhea; also used for some viral STIs. Highly sensitive and specific.
2. Blood tests (serology): Used for Syphilis (RPR/VDRL screening, FTA-ABS confirmatory) and HIV (antibody/antigen testing).
3. Bacterial culture: Can identify Gonorrhea and is useful for antibiotic susceptibility testing.
4. Pap smear: Screens for HPV-related cervical cell changes.

Screening should include routine testing for high-risk individuals (multiple partners, history of STIs, men who have sex with men) and prenatal screening for pregnant women to prevent vertical transmission.

Prevention Strategies for STIs

• Barrier methods: Consistent and correct use of condoms during vaginal, anal, and oral sex. Dental dams for oral-genital or oral-anal contact.
• Vaccination: The HPV vaccine prevents cervical cancer and genital warts. The Hepatitis B vaccine prevents sexual transmission of HBV.
• Regular testing: Enables early detection and treatment, reducing the window for transmission.
• Partner communication: Open discussion about STI status and testing history between sexual partners.
• Reducing risk: Fewer sexual partners or mutual monogamy lowers exposure risk. Abstinence eliminates sexual transmission entirely.
• Education: Sexual health education programs in schools and communities are a cornerstone of prevention.

Public Health Measures

• Contact tracing identifies and notifies individuals who may have been exposed so they can be tested and treated.
• Antibiotic stewardship promotes responsible prescribing to slow the development of drug-resistant strains, particularly in Gonorrhea, where resistance is a growing concern.
• Public health campaigns promote safe sex practices and reduce stigma around testing.
• Ongoing research focuses on developing new vaccines and treatments, including efforts toward an HIV vaccine.

Main Drug Classes for STIs

Benefits vs. Risks of STI Treatments

• Antibiotics effectively cure bacterial STIs and prevent complications and transmission. Risks include allergic reactions (especially penicillin allergy), GI side effects (nausea, diarrhea), and the development of antibiotic resistance with misuse or incomplete courses.
• Antivirals reduce the severity and frequency of HSV outbreaks and, in the case of ART, prevent HIV progression and reduce viral load to undetectable levels (which also prevents transmission). Side effects can include nausea, headache, dizziness, and potential drug-drug interactions. ART regimens require careful monitoring for renal and hepatic toxicity.
• Antiparasitics (Metronidazole) effectively cure Trichomoniasis and prevent transmission. GI side effects are common. Patients must avoid alcohol during treatment and for at least 48 hours after, because combining Metronidazole with alcohol causes a disulfiram-like reaction (severe nausea, vomiting, flushing, headache).

Nursing Considerations for STI Medications

• Assess for drug allergies and contraindications before administering any medication. Penicillin allergy is particularly relevant for syphilis treatment.
• Educate patients on proper dosing, duration, and potential side effects. For example, Doxycycline should be taken with a full glass of water and the patient should remain upright for 30 minutes to prevent esophageal irritation.
• Monitor for adverse reactions and treatment effectiveness. This includes follow-up testing to confirm cure for bacterial STIs.
• Encourage adherence to the full prescribed regimen. Incomplete antibiotic courses contribute to resistance.
• Maintain confidentiality and provide a non-judgmental environment. Stigma is a major barrier to patients seeking care.
• Emphasize partner notification and treatment. Treating only one partner leads to reinfection. Many states allow Expedited Partner Therapy (EPT), where medication is prescribed for the partner without an office visit.

Patient Education for STI Therapies

• Provide clear, written instructions on how to take the prescribed medication (timing, food interactions, what to avoid).
• Stress the importance of completing the full course of treatment, even if symptoms resolve early.
• Advise patients on common side effects and when to seek medical attention (e.g., signs of allergic reaction, severe GI symptoms).
• Recommend using barrier methods (condoms) during treatment and until follow-up testing confirms the infection is cleared.
• Schedule follow-up testing to confirm treatment effectiveness, typically 3-4 weeks after completing antibiotics for Chlamydia or Gonorrhea.
• Offer resources for emotional support and counseling, as an STI diagnosis can cause significant anxiety and relationship stress.
• Reinforce preventive measures to reduce the risk of future STIs, including regular screening and vaccination where appropriate.