I am visiting a friend for a few days and was expecting to have sexual contact with him (MSM) during my visit. 

In order to engage in safe sex we did the following: He got a HIV, Vdrl negative test 5 days before meeting. However, this was only 10 days after his last encounter (he was anal top, with condom, with person of unknown status), so I reckon this is early. He also took prep on demand, but did so incorrectly (1 pill 30 hrs before sex, and 2 pills after). 

We met Wednesday night and Friday morning, where we only had mutual masturbation, I can expect his presume touching my urethra, as he gas stimulating the glans a lot. 

Friday afternoon (1. 5 days and hours after we met) I took 100mg doxy as pep, and another 200gm around midnight as I was scared 100 was not enough. I plan on continuing regular dose these next couple days we will meet. 

Around 4am (48 hrs after first encounter) and 3 hrs after doxy I took HIV on demand prep (2 pills) as I expect to engage in anal. 

1 min after taking pills I got a horrible uncontrollable shivering and felt feverish and hot, lasted for 10 min and after 30m it break through, sweat and gone, with 0 other symptoms. Woke up all fine. 

1. Could that be prep meds caused me a reaction? Maybe doxy + pep? 

2. Could fever be HIV or STD related given facts and time-line (is 2 days too soon for hiv fever?) It puzzles me I got a misterious fever while on doxy (300 mg that day) so it must be viral. 

My friend also got a C/G test done Friday which we will wait for. 

3. If I continue my on demand pep and doxy with condom, am I safe to engage in anal? 

Can I have unprotected sex with my regular partner unprotected after the fact? 

1. Indeed, onset of these symptoms after only a could have been an allergic reaction. Doxycycline is rare cause of immediate allergy, but I cannot rule it out -- but the HIV PrEP might be more likely. Such immediate onset of these symptoms could predict an even more serious reaction next time; I suggest you avoid taking any of these again until you have consulted your own physician.

2. Given the nature of the exposure (condom protected) and HIV drugs, HIV is very likely and cannot cause symptoms so soon. Neither can other STDs. Here too, your doctor should be the source of further advice.

3. As noted above, it would make sense to avoid any of these drugs until your own doctor has advised you; and therefore probably smartest to avoid further sex (with anyone) until then.

Good luck.

HHH, MD

I took doxy because we engaged in unprotected oral. Won't take prep anymore. 

2. Understood exposure is low risk, and even then, HIV cannot cause symptoms so soon. 

3. As per 1, I understand I should not take any more meds. Because of that I will avoid sex with my friend. Just want to clarify why you suggest avoiding sex with anyone, including my regular partner? 

2. True -- not before 7-8 days, usually 10-20 days after exposure. And fever and chills never would be the only symptom.

3. You've just had sex with a potentially unsafe partner. Although the chance of an STD is extremely low, I cannot say it is zero. It's up to you, and what you think your partner would expect.